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ADA Preamps => Original MP-1 => Topic started by: herbyguitar on October 20, 2017, 09:56:27 PM

Title: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 20, 2017, 09:56:27 PM
I'm considering doing an overhaul to my MP1 V2. I have replacement tubes. I'd like to also replace internals that should be replaced (caps, transformer, whatever needs replacing). I've already done the battery mod. I 'think' I'd also like to install a MOD4.

Reason for choosing MOD 4: Marshall. It's the only mod that doesn't have cons in the descriptions and also does not sacrifice too much of the clean tube sound... besides, I like the idea of harmonics (it was in the description). Something hard to come by with a strat. I don't need a lot of gain. I know what I want... I think. I just don't know if I'm up to doing it myself... schematics are Greek to me.

Also, any advice will be appreciated.

Alternative: Overseas shipping and labor to have this done would be expensive...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 21, 2017, 08:53:33 AM
Well... after doing a lot of searching, reading, and weighing the differences. It sounds like what I'm looking for is more in the 3TM mod. It looks like everyone really likes the transformer swap also. So... I'll be changing directions.

Is there anyone reliable in the US that can do these mods? [edit] Nope. I'm doing it myself. Wish me luck...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 22, 2017, 04:08:44 PM
In the 3TM mod there is a trim pot that's added to the main board. What does this pot do?
Title: Re: Herby's attemt @ Mod 3TM
Post by: rnolan on October 23, 2017, 02:31:14 AM
Hey herby, I suspect the trim pot is a gain adjustment  :dunno: , but others will know better than me.  If you don't want outrageous gain and want to keep reasonable clean sound capability, then I don't think 3TM is the way to go for you.  E.g. MJMP uses a 3TM for distorted sounds (coz he plays metal  >:D ) but uses a MP-2 for cleans.
Re doing it yourself, we can help talk you through it, it isn't (mostly) too hard to do.  You do need a decent temperature controlled soldering iron, though they are not that expensive (eg a Duratech TS1513 (which I bought) or similar) and a few other bibs and bobs (like a solder sucker and/or solder wick).  That said, any decent tech should have no problems doing the mods for you, buy the bits from MJMP (or source yourself) and get them to follow the instructions.
You don't need to understand schematics, all you need is the PCB layout to locate/find the various components you need to change out.

This is what I would do (advice LoL):
If your unit is a V1 (ie inst/line switch on top), do the rear jack mod first (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm) this will get you into it, replace the front and rear input jacks and turn the rear jack into inst level (and isn't hard to do).
Do the MDRT and a new tube board, I'd go with the SS Mod tube board (http://www.marshalljmpmodshop.net/ada%20mp1%20ss%20mod.htm), a bit more gain, but otherwise upgraded stock tubeboard, modernised.  Now IIRC the MDRT install requires a change on the tubeboard, so get it from MJMP MDRT ready (and a MDRT) and do them at the same time (this should be rather easy to do and you wont have to change the tubeboard component(s)).  The only place you can buy a new MDRT is from MJMP, he gets a batch of them made from time to time to keep us all happy  :thumb-up: .  So it makes sense (well to me) to just get him to send everything you need (a nice little box will turn up with all the bits and include ADA Depot stickers  :whoohoo!: ).

And last, do the noise mod, this is changing out the old caps.
Oh and maybe EPROM ?  The last EPROM is 2.01, when you turn the unit on it will display the version.
Then either get a tech to do it (in the order above, or all at once), or do it yourself with some help and encouragement from us here  :thumb-up:

Harmonics you can chase (to some extent) with tube choice eg try a pair of New Sensor Mullard Long plates (http://www.dougstubes.com/preamp-tubes/12ax7-ecc83-7025/mullard-12ax7.html), they just sing mmmm
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 23, 2017, 08:03:13 PM
I have never run the (stock) MP1 full gain. I'm pretty sure there's plenty of gain at hand for me. I just need tighter and quieter. The tone of the (stock) MP1 is fine. EQ wise, I have a 3 band parametric and a 7 band linear in the 1101 which is running after the MP1. I won't be adding anything to the front end or the effects loop of the MP1. Things in front seem to always add noise.
Title: Re: Herby's attemt @ Mod 3TM
Post by: rnolan on October 24, 2017, 05:27:22 AM
Hey Herby, I think the MDRT will do just what you want, (based on how it sounds in Mikes MP1 (tighter, quieter, and more dynamic)).  I've never run anything in front of an ADA preamp (well maybe a tuner), I know some do and it works for them.  Apart from the MDRT, my other suggestions are about modernising the unit and further reducing noise.  Tube choice will also play a part (but we've discussed elsewhere).
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 26, 2017, 10:13:05 PM
I weighed all the options and expenses (which would be substantial) of fixing the MP1 and decided the cost and uncertainty isn't worth it. The MP1 goes back into storage. Instead of trying to resuscitate a one trick pony I'll just work with my 1101.
Thank you all for your help and insight.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 28, 2017, 12:46:03 PM
...well. I've moved away from my (being totally confused, overwhelmed, crouching in the corner) position and back to reality. The MP1 just sounds way too cool to give up now. I'm going to go the SS, noise, MDRT route. "Whew" ... that was a tough decision.

[edit] Sent payment and waiting for parts...
Title: Re: Herby's attemt @ Mod 3TM
Post by: MikeB on October 28, 2017, 04:11:44 PM
You have made a good decision. I've done the same thing and it sounds amazing.  :banana:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 28, 2017, 10:56:59 PM
@MikeB!!! I've been waiting for your input! Thanks for chiming in. I feel much better now. That's exactly what I needed to hear. Thank's man  :) 

Thank you all for putting up with my crazy quirks  :D 
Title: Re: Herby's attemt @ Mod 3TM
Post by: MikeB on October 29, 2017, 10:44:30 PM
Happy to help.   You were jumping around so much that i want really sure what it was you were looking for.  I hope this choice makes you happy.
Title: Re: Herby's attemt @ Mod 3TM
Post by: Soloist on October 30, 2017, 11:59:36 AM
Hey there Herby, I noticed that you also have an 1101. I run my 1101 and MP1 using gsp set up #6 in the manual. It allows me to use either the 1101 preamps or the mp1. It also allows me to use all the 1101 effects in their proper position. .i.e. the noise gate first. It eliminates all unwanted noise from the mp1 while preserving it's tone. It takes a little tweaking but once you get it, the tones are amazing!
Title: Re: Herby's attemt @ Mod 3TM
Post by: Systematic Chaos on October 30, 2017, 06:02:42 PM
+1 on what Soloist said. That's the way I ran my MP-1/1101 back then. This will also allow you to tighten up the MP-1 by placing one of the 1101 internal ODs in front of the MP-1
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on October 30, 2017, 07:13:04 PM
Yup. I was bouncing around a lot. I was wracking my brain trying to figure out what mod would get me what I wanted but it seemed that there was none and I'd have to compromise... then I gave up and took the MP1 out of the rack. 2 days later I pulled the trigger on what rnolan and MikeB suggested.

I ran mine the same way. I hate the way the gate works in this position though. I lose a lot of dynamics. The gate interferes with the signal too much. You can't roll off the instrument volume without choking the signal. The gate works much better at the end of the chain. That's why I switched to running the 1101 behind the MP1. I would like to run the #6 position again and also add a separate gate at the end. This way I'll have the best of both worlds.
Title: Re: Herby's attemt @ Mod 3TM
Post by: Soloist on October 30, 2017, 11:31:53 PM
Yup, I run another gate with my G major 2 after the mp1.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 02, 2017, 05:47:14 PM
I was running #6 in stereo. The MP1 was mono but the 1101 was stereo out. After I do the mods I'm going to put a gate behind the 1101 and run #6 again.

[edit] I changed the title of the thread to reflect the mods I'm attempting.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 14, 2017, 11:30:14 AM
Parts are in! I'll be starting on it shortly. Hope I can do this...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Soloist on November 14, 2017, 01:42:18 PM
 :thumb-up:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on November 14, 2017, 02:21:37 PM
Hey  Herby if you have any questions just let me know, big or small.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 15, 2017, 12:49:35 PM
I'm wanting to start with doing the noise mod. It seems to be the best place to start because the ribbon cable from the main board to the back board needs to be removed for easier access to the big caps and then before I put it back in place I'll do the transformer mod, then the tube board mod last.

My question is: The ribbon cable that is in the way. The long narrow plug is held in, I think, by small clips on both ends. How do I unplug this without breaking the retainers on both ends? I'm afraid to put too much pressure on them.

[edit] Well... I managed to get the clips to release and found out that all they do is hold the ribbon in the socket. The plug doesn't seem to want to come out of the socket. I've dealt with ribbon cables on hard drives but they were never this tight. This is new to me. How the hell do I deal with this? Do I just keep prying on it? I'm afraid I don't know what I'm dealing with.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on November 16, 2017, 03:52:08 AM
Sometimes they can get stuck and hard to get out, but I never had one that I couldn't get out. Try to rock it from left to right and see if it comes loose.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 16, 2017, 09:17:44 AM
OK. Just wanted to make sure that I didn't break something.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 16, 2017, 12:57:30 PM
I'm having an extremely hard time getting the old IC socket out. This seems impossible without wrecking something. My solder sucker does not work on this. I'm afraid to get things too hot. Any advice?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on November 16, 2017, 01:38:31 PM
What IC socket?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 16, 2017, 01:54:28 PM
The one you sent me in the noise mod. I finally got it out. I had to cut all the legs then pull them out one by one while heating them

[edit] I think I've ruined the board where the IC socket goes... A couple of the solder grommets are gone. I'm afraid I've made a very expensive boat anchor. If it wasn't for this one piece this whole mod would be a piece of cake.

[edit] I'm going to keep going. I've installed the IC... maybe it will still work...
The next piece is the 270pF cap. The one in the kit says 250 +- 5% v SM500 ??? Does it matter which way it goes in?

[edit] I installed the cap and hope it doesn't matter which way it goes. Diode is in correctly. Main board noise mod is done... hope the IC works...

[edit] With this all in place can I plug it in to see if the MP1 still works? I haven't done the SS mod or the MDRT mod. If the MP1 doesn't work I don't want to waste the SS or MDRT mods.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on November 17, 2017, 12:11:28 AM
Hey Herby, can you post some pictures of the IC socket from top and bottom of PCB, if the pads (I assume you mean by solder grommets) are lifted, you may need to run a couple of wires but MJMP will need to see whats happened.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 17, 2017, 03:46:15 PM
I can't show the top because the socket is covering it. The top looked OK before I seated the socket. The bottom doesn't look so good. It looks like I may have to run 2 jumpers.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on November 17, 2017, 03:55:57 PM
The cap has no polarity, as for the opamp, well many people struggle with it. Even I lift a pad sometimes. Now it's good that nothing has lifted on top, so if it happends on the bottom just run some small thin jumpers.

Say if you have questions, just email me, this will go faster.

Yes you can try it out without the MDRT and SS mod, no problem.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 17, 2017, 06:15:30 PM
I looked it over on bottom and there are 2 traces that lead to pins but those two still have the pads. I'm going to plug it in and see what happens. I'm sure I'll know pretty quick if there's something wrong. If I need to connect a couple of top traces I'm pretty sure I can do this. I ran into trouble trying to clear the grommets of solder. Can someone tell me the best procedure for doing this (for future reference)? All other mods are simple except for IC's. These are extremely difficult because of the compound desoldering and evacuation of the grommets.
 
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 18, 2017, 01:25:03 PM
It doesn't work. I get a split second flash of one red LED when I turn it on. Looking the socket over I've come to the conclusion I should have never tried to do this. To remove something this small and with 8 different contact points is almost absurd. I ran into trouble not from removing the socket but in trying to clear the holes of excess solder so the new socket could be inserted.

With the new socket in place and the areas around the socket are so tight and I'm too inexperienced to attempt any kind of fix. 'WAY' above my pay grade.

For anyone contemplating any future mods that incorporate swapping out an IC socket. DON'T attempt it unless you are a professional. You're chances of failure are extremely high.

Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 19, 2017, 07:46:03 AM
Anyone need an MP1 for parts?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on November 19, 2017, 08:33:50 AM
Wow Herby, don't give up so easy, this can be fixed, doesn't seem to be so bad.I've seen far worse then this. Maybe we can do a skype session next week so I can help you out finding the problem.Do you have a multimeter?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 19, 2017, 08:49:49 AM
I sent you an email explaining what happened.
I'm an idiot!!!
When I started this project I unplugged the large ribbon cable to gain access to the large caps. I was so preoccupied with installing everything and then messing up the IC socket that when I tested the MP1 with only the noise mod installed I forgot all about the ribbon cable. This morning I tried it again and it still didn't work so I put it back on the work bench and was staring at it in disgust when my eyes wandered over to the large socket where the ribbon cable was supposed to go. It was empty...   :facepalm:

I reattached the cable, plugged in the MP1, and guess what? IT FRIKKIN WORKS!!!! I spent the next 20 minutes jammin :banana-guitar:

I hope I'm not the only one to ever make a stupid mistake   :o

So now, it's on to the MDRT mod and then the tube board SS mod
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 19, 2017, 09:58:42 AM
New transformer is in. No troubles. All is well. This was simple. I like simple ^-^
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Kim on November 19, 2017, 10:13:10 AM
Yes they are a PITA.  It's a slow process that requires a bit of patience....not like installing them at the factory when everything can just be wave soldered and go, that's for sure.

If you think you might want to send it to someone to get that sorted, I may be available to do that.  I'm in Wisconsin, btw.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 19, 2017, 11:45:37 AM
Thanks for the offer Kim. I just finished everything.

Verdict: ... IT'S ALIVE!!!   >:D

Just finished testing. I cranked it up and put OD1 and OD2 both on 10. It's quiet and cleaned up very well. Just enough gain for metal and my SC strat. Kept all those nice overtones as well. It's like it cut the distortion but kept everything else. I'm very pleased.

Now all I need is a gate for the back end. Actually... I may not even need a gate on the back side. I should be set and running by next weekend   8)

[edit] Last questions:
1) Is there any adjustments I should do with the internal trim pots?
2) On the tube board, which sockets are V1, V2?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on November 19, 2017, 05:24:11 PM
Congrats!
V1 is the closest tube to the front, V2 the other.
Check the Stock Gain Mod instructions (http://adadepot.com/mods/ADA_MP-1_Stock_Gain_Mod_Doc.pdf) for the OD Trimpot (T2) adjustment:
Step 10: Tweaking the OD1 Trimpot
Here is how to set the input stage gain-trim:
1) Plug your MP-1 back into your rack, make sure you have ample access to the top of the unit.
2) Locate the OD1 Trimpot you replaced in steps 6 & 7.
3) Dial-up your favorite high-gain patch.
4) Grab your main axe, plug it in, and switch to your bridge pickup.
5) Set the OD1 Level Control to 5.0 or 6.0 (or 7.0 depending on your pickups). You will have to play
around with this setting until you are happy with how the other channels sound, especially the Clean-
Tube channel. I wouldn’t let this setting get above 8.0, it may get too muddy or noisy.
6) While you are doing palm mutes and/or heavy open chords (“Pull Me Under” is a good riff to test
with BTW), have your little brother turn the trimpot dial with a little miniature screwdriver until the
OD1 Clipping LED lights up frequently on downstrokes, but doesn't stay lit all the time.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on November 20, 2017, 05:53:34 AM
You scared me a lot mate!  :lol:

I've to replace some caps and one IC on my MP-1...  :lol: :lol: :lol:

Now I know I've to pay attention to ribbon cables connectors!  :banana:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on November 20, 2017, 06:30:24 AM
Yep without the ribbon cable the mp-1 won't fire up, that's normal.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 20, 2017, 05:14:13 PM
Well??? I could have lied about it   :dunno:
Anyway. I'm documenting the trials and tribulations of a novice Electronics Technician and possibly giving good (what not to do) advice :P
The 3 mods were actually very easy, suffer a few burns and that pesky little opamp...

I'd like to try some different tubes. I've got JJ ECC 83s in both V1 and V2. They sound good with a lot of gain but a little dull. I'd like to keep one of them and change out the other. The 2 below have been highly recommended.
Mullard  ECC83 / 12AX7 long plate.
Mullard CV4004 / 12AX7 short plate.

What is the difference in gain?
Which tube is going to give me a more articulate low end?
Which slot to change, V1 or V2?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on November 20, 2017, 07:57:36 PM
For articulate low end put a TAD RT001 (12AX7A-C) in V1 and one of the Mullards in V2. V1 (in combination with the OpAmp in U4) sets about 80% of your gain characterics/tone. V2 amplifies that and adds the icing on the cake.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on November 21, 2017, 03:02:06 AM
The long plate Mullard is a bit more 3D than the short plate and really articulate (nice) low end.  Careful though, the long plates are so subtle they track every little pressure change in your fretting  >:D . They are very articulate tubes.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 21, 2017, 02:28:09 PM
I've got one each coming.

Mullard  ECC83 / 12AX7 (long plate)
TAD RT001 (12AX7A-C)

Thanks guys for the input.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on November 21, 2017, 04:09:26 PM
You won't be disappointed!
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on November 22, 2017, 02:27:02 AM
You won't be disappointed!
+1  :thumb-up:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 22, 2017, 01:38:59 PM
A couple of questions: MP1

1) Anyone know where "flat" is on the MP1? Is it @ 0, 0, 0, 0, or is it somewhere else?

2) Is this all I need to change the bass center point? (replace R168 (5k1) with a 10k trimpot). I found that in another thread. I'd like to move the point down off the low mids and more into the bass area. Maybe around 80 hz (thoughts) ???
I can do this with a parametric but it would be more effective to also alter the bass frequency middle point.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on November 22, 2017, 02:17:04 PM
A couple of questions: MP1

1) Anyone know where "flat" is on the MP1? Is it @ 0, 0, 0, 0, or is it somewhere else?

2) Is this all I need to change the bass center point? (replace R168 (5k1) with a 10k trimpot). I found that in another thread. I'd like to move the point down off the low mids and more into the bass area. Maybe around 80 hz (thoughts) ???
I can do this with a parametric but it would be more effective to also alter the bass frequency middle.

1) 0 is flat / noon

2) check Step 10 in the Mod3.666 instructions (http://adadepot.com/mods/ADA_MP-1_MOD3.666_Hi-Res.pdf) This lets you fine-tune all Treb/Mid/Bass circuitry in the MP-1 individually to your desired sweet spots
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 22, 2017, 04:47:57 PM
When I set my OD1 to 10 the OD1 light in front stays lit. Is this supposed to stay lit with this much gain? I've never set it this high before so I don't know. I also get a very slight 'after' squeak or squeal on some notes. I never noticed this before either, but then again, I've never played on 10 before. It was always too muddy to go this high.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on November 23, 2017, 02:40:29 AM
Yes that could be, now as soon as the led goes on there is no added gain anymore, it get's compressed with diodes. More gain will give more chance on getting feedback.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 23, 2017, 08:50:11 PM
Something is strange. Yesterday I posted about the OD1 LED. Today I tried to get it to light up but couldn't. It would not light. No idea why...
---------------------
Today I ordered a trim pot to enable me to adjust the bass frequency center...
---------------------
I'm getting a kick butt killer high gain tone from this MP1. I haven't done a lot of experimenting yet. So far I'm still working on high gain. (OD1_10, OD2_10, B_6, M_6, T_6, P_6). Bass is still loose but much better than it was stock. With some concentration and technique I'm able to tame it. Gonna have to work on my right and left hand string muting.

This is interesting because I'm learning that the tone is connected to the circuitry. Changing the circuitry will also change the characteristics and tone. "A fine line". I don't want to change the characteristics of the preamp too much. If I do I'll lose the reason I love it. So far it's been a positive endeavor.

I realize when I change the tubes I'll no doubt have to alter my playing to compensate for the added complexity that the tubes will insert into the mix. Tone is everything to me. Dealing with it is a challenge I accept. Hopefully the added trim pot will enable me to tune the bass to behave better.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 25, 2017, 07:34:14 PM
Tubes came today. 'Tad' went in V1 and 'Mullard' went in V2. This setup is much hotter than the JJs I had. More gain.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on November 25, 2017, 07:44:17 PM
Tubes came today. 'Tad' went in V1 and 'Mullard' went in V2. This setup is much hotter than the JJs I had. More gain.
...and way more complex yet articulate and defined I assume ;)
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 26, 2017, 08:11:35 AM
Yes it is more complex. The JJs are a tighter sounding tube but they're rather flat sounding. It's looking like I can't have it both ways. I either choose articulate or complex... The MP1, as it is now, has a killer and complex tone but it's not tight unless I play relatively clean with OD settings under 5. The lower I go the tighter it becomes, which is not really a bad thing especially for a strat but it does limit its usefulness. As a comparison my 1101 can produce a 'sickly' tight response but it sounds rather flat.

Bass trim pot is in the mail so I can't work with it yet...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on November 28, 2017, 01:48:33 AM
What I found when I changed from Boogie STRs (re-branded JJs) to Mullard long plates in my MP2 was:
Didn't fart on the bottom E (~82hz) as it did with the JJs
Any ever so slight change in left hand fingering pressure (and position between the frets (and I'm talking very very slight) was clearly articulated (very 3D)
A nice balance across the frequency spectrum, the JJs were on the middy side and quite 2D.

I was an instant convert, however, the JJs had the best feedback  :thumb-up:

Playing with max gain (ODs on 10 & 10) will be a new world, it's ultra sensitive and you need to learn taming techniques.  I learn't them early using a 73 Marshall turned up as loud as it would go.  The MP1 is much easier to tame, but hi gain is what it is  >:D
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 28, 2017, 04:14:02 PM
How did you get it to not fart (open E)? Mine farts badly unless I turn the gain down to about 5. I've played through Marshalls before and they are much easier to tame than my MP1 but the MP1 has a much better overall tone. Especially with the tube swap. I've been playing for a very long time and I don't think my technique is that lacking.

It reminds me of an overdriven Mesa. Chords are killer and single (upper register) notes are extremely musical but lower notes suck.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on November 28, 2017, 05:43:23 PM
Easy workaround....re-adjust the Trimpot. Set OD1 to 10 and chugg. Adjust the trimpot so the OD1 light ocaasionally lights up while heavy chugging E5 powerchords.
Very simplified: OD1 is "Drive" and OD2 is "Saturation"
The farting you mentioned is probably U4 getting too much input
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on November 28, 2017, 11:36:13 PM
Hey SC, good advice  :thumb-up: .

I never had any issues with my MP1 when I had it.  In all the years I gigged with it I only did one tube swap and put in some Boogie STRs (JJs) which worked fine.  When I finally did a tube swap in my MP2 I initially put in a pair of Boogie STRs as I could buy them locally.  When I cranked it up at a rehearsal is when I had the issue on the bottom E, it didn't so much fart  :dunno: just broke up.  I'd ordered some Mullard LPs and put them in as soon as they arrived, and it was just soo much better, but that's for how I play.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on November 30, 2017, 02:55:59 PM
I installed the trim pot as per instructions. I can rotate the pot and hear the bass frequency shift. It works as it's supposed to 'but' now I have serious issues. The volume went way up and there's intermittent static. Also the volume knob on the front of the unit does not work. It's like the unit is set to full volume. All I did was take out the small resistor and replace it with a trim pot modified as per instructions. I also installed the bottom cover which was not in place the last time I tried the unit. That's all I did. Anyone have any clue as to what happened?

Huge "Brain Fart"  :facepalm:  I had something hooked up wrong. My bad. I hooked the MP1 back into the rack without testing it first (stupid). It's all "Good".

Set the bass trim pot around 100Hz. Much better. I reduced the highs and boosted the presence and it cleared up pretty good. Then I put all gains on 10 and it stayed articulate. No external EQ.

I hooked up my 1101 and ran config (6) in stereo. Now I have both the MP1 and the 1101 running stereo. Things are looking pretty good. I think I'm done   :banana-guitar:

Now to put everything back together and start setting up my presets   8)
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on November 30, 2017, 10:06:56 PM
Good news for modern man  :thumb-up:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 06, 2017, 02:40:19 PM
Well, I'm having a good time with the new setup. The mods did clean up the low end but the new tubes reversed the process somewhat.

A little experimenting and I've narrowed down my search for the culprit. I started with The MP1 OD 1 & 2 set to 5.0. All EQs set to 6.0. I then set a medium band on the parametric @ 2KHz. Cut -6db and started panning down until I hit 850Hz. Here's where things started to clean up significantly. Going lower didn't help any. it actually made it worse again. Once @ 850Hz I selected a narrow band. As This opened up the sonic goodness a bunch. I experimented going higher and lower but 850Hz seems to be the best place and a -6db cut seems to be a good choice also. It's right on the edge between tonal quality and clarity.

As for the new tubes: Systematic Chaos said I'd like the combo and he was right. The TAD is a hot and nasty (in a good way) tube. Mullards are a very good choice for V2 but, as rnolan stated several times, They're not very forgiving. When you're 'ON', they're extremely kick ass. When you're 'OFF'... let's just say they don't play well with inaccuracies.

I did also notice something else with this combo of tubes. With a little technique, they have an odd way of making an off note sound good... but the noise is back and the farting low end is more pronounced.

Waiting on 3 short AC chords so I can batten down the hatches in the rack...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on December 06, 2017, 03:04:10 PM
 :thumb-up:
...and now just slowly bend that off-note a half step and it sounds even more killer ;-) (Marty Friedman style)
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 11, 2017, 09:04:42 PM
Well... I blundered again. I left out the addendum to the noise mod. My reasoning was that it was part of the old mod and not applicable. Wrong. MJMP straightened me out and I finished up the addendum and put everything back in the rack. It's done. Finally :thumb-up:

I found that using a noise gate after the MP1 doesn't work very well and I'm not sure why. Got rid of the Furman and added a protected power strip in the rear. So there's only 4 things in the shallow 12" 4 space rack: Line6 Relay G55 (Guitar), Line6 XDV55 (Vocals), MP1, 1101. 1/2 space gap on top and bottom of the MP1. 2 80mm AC fans in the rear.

The Mesa Two 50 is in its own shallow 12" 2 space rack.

Only requires 2 chords dropped from the 4 space to the 2 space.

Easy to haul. Clean and simple.

Good enough for me. It's done.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on December 12, 2017, 12:21:07 AM
 :whoohoo!: looking good  :thumb-up: .

The built in gate/NR in the MP-2 is after the graphic eq, so signal is still mono and feeds into the chorus stage (where it goes stereo). So maybe (if you need a gate, I never used one or seemed to need one with MP-1) you could put it in the MP-1 loop, which is IIRC just before the chorus (again where it (MP-1) goes stereo).
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 12, 2017, 03:10:51 PM
I might try that.
I don't like using a gate but I have to. The line 6 wireless adds a little noise and so does a gain boost. Using a boost is the only way I've found to run the MP1 hot and not have a farting bottom but cleaning it up and running the gain from 3.0 to 5.0 makes for a very nice old school R&R tone and no farting.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on December 13, 2017, 01:25:50 AM
Have you tried just running straight into the MP-1, nothing else in front ?  Everything you go through will add some noise and often colour the sound.

But in the set up you're using, you could also try the gate after the wireless (to get rid of it's noise as the boost will boost that noise as well as the signal), then the boost will add some noise and probably colour also.

Anyway best to try the options and hear what works best.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 13, 2017, 03:56:25 PM
I've discovered the MP1 has:

An intermittent break up while playing. A crackling noise accompanied by volume fluctuations (this doesn't happen all the time).

When the gain is up around 8.0 and I turn up the preamp/amp, it starts to sing (no guitar, no input). At about 1/3 output.

There's a very strange pulsating hissing noise that happens at regular intervals (every 6 seconds), like an old dial telephone when you grab the '0' and crank it around, then turn it loose.

I have no idea where to go with this now.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on December 14, 2017, 04:21:13 AM
Is it affected by patch setting ?  is chorus on ? (I'm guessing something to do with the bucket brigade circuit ?? due to your old phone reference)
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 14, 2017, 01:49:31 PM
Chorus is off. So is loop.
What is "bucket brigade circuit?"
I may have more than one issue going on here... Is there a chance I may also have a bad tube? I'm thinking of the singing when turned up.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Systematic Chaos on December 14, 2017, 03:29:20 PM
2 things that come to my mind instantly:
- bad tube
- bad Vol pot
Iḿ sure MJMP will chime in shortly
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 14, 2017, 04:20:20 PM
I took out the Mullard and the strange fluctuations and 1/2 of the noise went away.
It's still too noisy to run over 6.0 gain without a gate. Seems like it's not really any better than stock.
I think I need to have someone look at it and find out what's wrong...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 15, 2017, 12:52:03 PM
@MJMP : If you will consider it. I may want to send it off to you and have you fix it...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on December 15, 2017, 02:22:08 PM
I just send you an email.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 15, 2017, 11:00:35 PM
@ MJMP : You're awesome!
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on December 16, 2017, 03:38:25 AM
No problem  :thumb-up: that's why I'm here  ;D
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Soloist on December 21, 2017, 11:59:46 AM
Hey Herbie, once you get your MP1 straightened out try routing #7 for the GSP. I just did that on mine and I found I get way more control over the noise gate and the effects sound livelier.  Sounds better sonically and way more dynamics in my tone.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 21, 2017, 03:11:06 PM
Thanks. I was looking at that a while back. I'll have to try it.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 18, 2018, 06:03:14 AM
I've discovered the MP1 has:


When the gain is up around 8.0 and I turn up the preamp/amp, it starts to sing (no guitar, no input). At about 1/3 output.


Sorry mate...a question, since I (still) have to fix a similar issue with mine (V2.1, same mods) since some months (components are ready...I just need to find the time to do the job...).
Is it like a high pitched squealing noise? And does it start appearing when you turn the front Output Level pot over 1/3 and becomes worst over its halfway?

@MJMP: Phil, what do you think about, mate?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on January 20, 2018, 07:22:56 AM
Did you try to replace those parts we talked about?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on January 21, 2018, 08:29:27 AM
@Iperfungus: Yes, high pitched and it starts around 1/3 to 1/2 volume. It could also be proximity to the unit with the SC Strat. I'm not too concerned with it yet though. I change tubes and it goes away (always buy from good source that tests their tubes). I think it's one of the new tubes. Probably the Mullard. My biggest problem is in the mid frequency hum that is unbearable at any stage. Not sure where it's coming from but it wasn't there before the mods. I think I've got a messed up ground somewhere...

@MarshallJMP: Been a little strapped for funds (Christmas and Taxes took a lot out of me) so my shipping the MP1 to you will be a little longer.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 22, 2018, 03:23:32 AM
Did you try to replace those parts we talked about?

Not yet mate...but I planned to do the job in the next days.
I'm always overloaded with stuff...  :dunno:

I was just curious about herby's MP1, since it has the same mods and a similar issue...even if I had not the same luck with tubes rolling.  :lol:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on January 22, 2018, 10:43:49 AM
Well I thought about something, with the higher MDRT voltage, the output voltage of the tube board will also be higher, maybe with some tubes it could be to high for the digital pots. I'll do some experimenting this week, see what I can figure out. Now should this be the problem you can easily solve it by replacing one resistor on the tubeboard so the input voltage on the digital pot is lower.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on January 22, 2018, 11:55:48 AM
I'm also having similar issues. Max had been asking me to quantify my squeal but i haven't had an opportunity to get all scientific about  it. With my b200s out  of action, i have been using the mp1 with a cab sim and  going out to pa speakers. My higher gain patches became unusable. Even Turning the gain down a bit hasn't really helped and then if it did , it's not really the solution I'm looking for.  I will try to spend some time this weekend mapping out the limits of the squeal.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on January 22, 2018, 03:00:41 PM
@MarshallJMP: Would that have anything to do with my noise issue?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 23, 2018, 02:42:55 AM
I'm also having similar issues. Max had been asking me to quantify my squeal but i haven't had an opportunity to get all scientific about  it. With my b200s out  of action, i have been using the mp1 with a cab sim and  going out to pa speakers. My higher gain patches became unusable. Even Turning the gain down a bit hasn't really helped and then if it did , it's not really the solution I'm looking for.  I will try to spend some time this weekend mapping out the limits of the squeal.

Thanks a lot Mike!
That's my point as well: I would use my MP1 with my settings and with no squeal.  :banana:
Because with those mods the overall tone is absolutely great!

So...3 MP-1s....same mods....same issue.
But Phil has some ideas already...and that's what I assumed when I reported the issue...  :thumb-up:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 23, 2018, 02:43:45 AM
Well I thought about something, with the higher MDRT voltage, the output voltage of the tube board will also be higher, maybe with some tubes it could be to high for the digital pots. I'll do some experimenting this week, see what I can figure out. Now should this be the problem you can easily solve it by replacing one resistor on the tubeboard so the input voltage on the digital pot is lower.

f**king great mate!!!
That makes sense about MDRT, tube board and higher voltage.
So I'd better wait to replace that OP and those caps we spoke about for this issue with the squeal?
I also used different tubes there but with no improvements...

Are we working on a fine tuning of MDRT mod here???  :headbanger:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on January 23, 2018, 02:57:36 PM
No not really, I want to lower the output of the tubeboard a bit. Not sure if this will help but it won't hurt anything.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 24, 2018, 02:40:06 AM
No not really, I want to lower the output of the tubeboard a bit. Not sure if this will help but it won't hurt anything.

So, are you going to reproduce the issue and attempt the fix on the tubeboard?
That's an approach that I share a lot.

You must use high gain settings....do you still have the ones I sent you?
If you need them, I'm here.
By the way, if you set OD1 = OD2 = 7.0, Master = 5.0, Bass = 6.0, Mid = 8.0, High = 10.0 and Presence = 12.0, you should reproduce the issue easily.

Now I'll wait for results of your test before opening the MP1 and replacing components.

Should the resistor fix not work, I can swap OP and caps as you suggested and see what happens.
Or you can do that as well.

We need to go step-by-step.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on January 24, 2018, 04:14:29 PM
...are you hijacking my thread?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 25, 2018, 02:38:13 AM
...are you hijacking my thread?

Me??? NO!!!  :lol:

Just looking for a solution for a common issue.  :metal:

PS. being serious, I can start a new thread if you prefer...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on January 26, 2018, 11:01:36 PM
Fight!  Fight!  Fight!....
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 27, 2018, 05:19:05 AM
Fight!  Fight!  Fight!....

 :lol: :lol: :lol:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on January 28, 2018, 07:53:06 AM
No fight. Just trying to limit other posts to relevant stuff. I know. That's an oxymoron because a lot of the time I'm not relevant
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on January 28, 2018, 11:51:11 AM
In this case it may well be relevant. It seems that you are having a similar issue to both Max and I and we have done the same mods as you. I'll certainly be watching with interest.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 28, 2018, 02:43:23 PM
In this case it may well be relevant. It seems that you are having a similar issue to both Max and I and we have done the same mods as you. I'll certainly be watching with interest.

Yep.
That's what I said some posts ago: 3 MP1s, same mods, same issues.
Issues that are related to this topic.

I discussed this issue privately with Phil/Mjmp several times and we made different hypothesis.
Now, after you guys reported the same issue, Phil had an idea and made an assumption about MDRT and tubeboard that makes sense (as usual, speaking about him).
I'm sure he's already testing the possible solution and he will be back with results soon.
Then, shouldn't this be enough, there's something more he suggested me to do during our discussions and that I didn't do yet (an OP AMP and 4 caps to be replaced): I would wait for Phil's results now.

By the way, if Herby prefers, as I said I can open a new topic and we can go on there.
Just let me know!
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on January 28, 2018, 04:37:03 PM
No. You don't have to open a new thread. Like you said. It's all related 
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on January 29, 2018, 01:29:07 AM
No. You don't have to open a new thread. Like you said. It's all related

 :thumb-up: :thumb-up: :thumb-up:

Usually this approach produced good results for other people in the future.
A common issue solved is a big added value!
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on February 15, 2018, 12:49:10 AM
Up!  :lol:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on March 22, 2018, 05:16:26 PM
I'm also having similar issues. Max had been asking me to quantify my squeal but i haven't had an opportunity to get all scientific about  it. With my b200s out  of action, i have been using the mp1 with a cab sim and  going out to pa speakers. My higher gain patches became unusable. Even Turning the gain down a bit hasn't really helped and then if it did , it's not really the solution I'm looking for.  I will try to spend some time this weekend mapping out the limits of the squeal.

Hey Mike....did you run any other test with the squeal issue with high gain settings on your MP-1?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on March 31, 2018, 10:41:29 PM
Hi Max,
Yes I did.  I didn't write anything down, thinking that I would remember, but of course I didn't.  So, I have just rerun some tests.
I have done this with both of my guitars.  I have done this with richards carvin ts100 as well as with my b200s.  I have even done this using a gcs-3 in the effects loop and going out to a headphone amp which pretty much proves that it is not a feedback issue.  I have done it with my gmajor2 in-line and active, in-line and bypassed and finally just going straight from my mp1 to the b200s.

I have an mdrt, noise mod and SS tube board.  I have a mullard short plate in 1 and Boogie STR in 2.

At one stage I used the gmajor2 parametric eq to isolate the frequency (but unable to completely eliminate).  It seemed to be at around 3000hz (this is the bit that I may have forgotten - Richard can you remember if this is what I said?).  Richard said it was around the Presence mark on the spectrum.  For the record, my mp1 is set up pretty flat.  Treble and presence are both 0, bass and mid not far away.

My main lead patch has OD1, OD2 and MV set at 6.5.  If any of those are higher then the squeal is present.

1. Keeping OD2 and MV at 6.5.  Adjusting OD1, the squeal is noticeable at 7.0 getting worse as the level goes up.  It is significant at 8.0
2. Keeping OD1 and MV at 6.5.  Adjusting OD2, the squeal is noticeable at 7.0.  Significant at 7.5
3. Keeping OD1 and OD2 at 6.5.  adjusting MV, the squeal is noticeable and significant at 7.0
4. OD1 on 10, MV at 6.5.  Adjusting OD2.  Noticeable at 5.5, significant at 6.0
5. OD2 on 10, MV at 6.5.  Adjusting OD1, Noticeable at 4.8, significant at 5.5
6. OD1 and OD2 on 10.  Adjusting MV, detectable at 5.0, significant at 5.5.

I quite like the tone that I can get even with these restrictions as it is so much better than it was before I did all the mods.  However, it seems crazy to be restricted to 6.5 on a scale that goes to 10.

MJMP, I am prepared to be the guinea pig for the resistor change, if you can tell me what I need to change.

Herby and Max, does this sound like the problems that you are having.  I had pretty much not thought about it for a long time because when it first started happening, I didn't map it out as completely as I have just done and MJMP said to just not put the levels up so high.  In retrospect, I should have pushed the point, as 6.5 is not really what I would call high.

cheerio,
Mike :waving-banana-smiley-emoticon
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on April 01, 2018, 10:52:25 AM
Your diagnostics sound about right to me as far as gain goes. I also agree with the limitations. My hum however is a lower frequency. more in the lower mids.
If it can be fixed without shipping it off to MJMP it would be preferable since he's in Europe and I'm in the USA. Shipping cost to Europe is crazy.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on April 01, 2018, 01:34:11 PM
Try to set the OD1 (T2) trim pot all the way down. See what that does.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on April 02, 2018, 10:45:44 AM
T2. Trimpot 2 on the board pic? Or is that the one by the tubes... on the main board sort of between the tubes?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on April 03, 2018, 01:54:05 PM
It's the one on the left side closest to the front panel.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on April 03, 2018, 05:47:05 PM
Hi Max,
Yes I did.  I didn't write anything down, thinking that I would remember, but of course I didn't.  So, I have just rerun some tests.
I have done this with both of my guitars.  I have done this with richards carvin ts100 as well as with my b200s.  I have even done this using a gcs-3 in the effects loop and going out to a headphone amp which pretty much proves that it is not a feedback issue.  I have done it with my gmajor2 in-line and active, in-line and bypassed and finally just going straight from my mp1 to the b200s.

I have an mdrt, noise mod and SS tube board.  I have a mullard short plate in 1 and Boogie STR in 2.

At one stage I used the gmajor2 parametric eq to isolate the frequency (but unable to completely eliminate).  It seemed to be at around 3000hz (this is the bit that I may have forgotten - Richard can you remember if this is what I said?).  Richard said it was around the Presence mark on the spectrum.  For the record, my mp1 is set up pretty flat.  Treble and presence are both 0, bass and mid not far away.

My main lead patch has OD1, OD2 and MV set at 6.5.  If any of those are higher then the squeal is present.

1. Keeping OD2 and MV at 6.5.  Adjusting OD1, the squeal is noticeable at 7.0 getting worse as the level goes up.  It is significant at 8.0
2. Keeping OD1 and MV at 6.5.  Adjusting OD2, the squeal is noticeable at 7.0.  Significant at 7.5
3. Keeping OD1 and OD2 at 6.5.  adjusting MV, the squeal is noticeable and significant at 7.0
4. OD1 on 10, MV at 6.5.  Adjusting OD2.  Noticeable at 5.5, significant at 6.0
5. OD2 on 10, MV at 6.5.  Adjusting OD1, Noticeable at 4.8, significant at 5.5
6. OD1 and OD2 on 10.  Adjusting MV, detectable at 5.0, significant at 5.5.

I quite like the tone that I can get even with these restrictions as it is so much better than it was before I did all the mods.  However, it seems crazy to be restricted to 6.5 on a scale that goes to 10.

MJMP, I am prepared to be the guinea pig for the resistor change, if you can tell me what I need to change.

Herby and Max, does this sound like the problems that you are having.  I had pretty much not thought about it for a long time because when it first started happening, I didn't map it out as completely as I have just done and MJMP said to just not put the levels up so high.  In retrospect, I should have pushed the point, as 6.5 is not really what I would call high.

cheerio,
Mike :waving-banana-smiley-emoticon

Thanks for testing Mike!
I 100% agree with you about all the better tones you get from MP-1 after those mods.
And I also agree with you that the squeal is not a feedback, also because I use home volumes here and it's there anyways...
It looks more like an oscillation, as MJMP suggested as well.

About the squeal, I get it with the settings of my main patch:

OD1 = OD2 = 7.5
MV = 5.5
Bass = 6
Mid = 6
Treble = 9
Presence = 12

I really love these settings, since the preamp has a very "plexish" tone...lot of details, no compression, tons of gain and open sound.
I loved it this way before mods and I love it more after mods.
The only problem with these settings is the squeal that comes out if I turn the front Output Level over 10-11 'o clock.
I did similar testing as yours and, at the moment, I can get rid of the squeal in 2 ways (without lowering overall gain, of course):

1) lowering Output Level (this means I cannot run outputs as high as I like)
2) lowering the EQ (this means I cannot have that "plexish" tone)

If I lower OD1-OD2-MV and EQ (bass, mid, high, presence) I can set Output Level to max without any squeal...but that's not MY tone.  :lol:

Internal trimpots for OD1 and OD2 have been set to minimum value already, after mods.

I also discussed the issue with MJMP by email and about the resistor he suggested to add a 100K resistor in series to R17 on the tubes board (430K --> 530K), to lower the input voltage of digital pots.
R17 is the more "external" of a group of 3 resistors in front of V2 socket.
As always, I'm very busy in these days and I did not find the time to do the job yet...but if MJMP confirms and you Mike would be the first one to do it....you're more than welcome!!!  :bow: :lol:
MJMP suggested to replace some other components at first, but now I would attempt the R17 mod before doing anything else...otherwise we'll never know if it worked 100% to solve the issue...

A couple of questions: did you find any difference about that squeal with different tubes? I attempted some tubes rolling as well but I found no differences.
And how do you set front Output Level pot's value?

Another test I've done is to use loop send or headphones out (stereo with an insert Y cable) instead of main outputs: in this way, if I set front Output Level pot to zero and I use loop's level pot or headphones level pot, there's no squeal even with my settings....but, as I turn Output Level pot over 10-11 'o clock, the squeal is there...even if I'm not using main outs.
This makes me assume MJMP could be right about oscillation and a too high input voltage somewhere.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on April 03, 2018, 07:50:15 PM
I wonder if the 3K hum can be related to the mid hum in some way. The only other mod I did aside from the mods that the others have done is the bass trim pot mod...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on April 04, 2018, 03:34:14 AM
I'll try the trim pot adjustment before I replace any components. But I won't get a chance this weekend.
It's funny, it never even occurred to me to adjust the output pot during my testing. I have mine pretty high, about 3 o'clock. I'll have to do some more playing around,  because I have plenty of headroom on the gmajor2 input pot.

I don't have any spare tubes to roll with.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on April 04, 2018, 03:38:45 AM
I'll try the trim pot adjustment before I replace any components. But I won't get a chance this weekend.
It's funny, it never even occurred to me to adjust the output pot during my testing. I have mine pretty high, about 3 o'clock. I'll have to do some more playing around,  because I have plenty of headroom on the gmajor2 input pot.

I don't have any spare tubes to roll with.

Yep!

You could try to lower the output pot until the squeal disappears...and see at which level...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on April 04, 2018, 04:50:25 AM
Hey Mike, presence is probably anywhere between 2.5khz to 6kHz.  In audio (mixer) land it's generally 5 or 6kHz, in mics (eg SM58) the presence hump is around 5kHz, and in guitar gear maybe a little lower (and varies on different gear), but 3kHz is definitely in the presence ball park (and hard on the ears when it squeals  :facepalm: ).

@ Max, interesting results with loop send and headphone out with output off.  So the loop send is before the chorus (IIRC after the eq, MJMP did post the signal flow a while ago), the headphone out is after the chorus (as is stereo) but before main outs (I think, or what you did wouldn't work), the headphone out also has rudimentary filters to reduce top end (similar to a cab sim).  So if you have lowered your trim pots to minimum (means with MDRT the tube stage is running much hotter  >:D ), this could be overloading the eq or chorus input ? (a guess  :dunno: ).

@ herbyguitar, the bass trim pot mod lowers the bass cut/boost centre frequency down to (IIRC) around 80Hz (bottom E in concert pitch is around 82Hz) from (again IIRC) 127Hz, there's a post MJMP put up that lists the centre frequencies of the eq bands, they're not listed in my MP1 manual.  But this is not low mid although harmonics (halving/doubling) happen. So 3kHz > 1.5kHz > 750Hz > 375Hz (375Hz is in the low mid/mud zone), or conversely 80Hz > 160Hz (always a problem frequency) > 320Hz.  I don't recall that others who did this mod had any introduced "hum" issues, it should be a problem, check you install though, make sure all is good and no solder or component issues, maybe trim pot needs a clean  :dunno: .

Interesting tit bit, when AKG D12 was made it was intended for male vocals and has a 80Hz boost (hence good on kick drum (add 2 or 3 kHz for click/cut), also the Bayer M88 was similar and a useful kick mic.

Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on April 04, 2018, 05:35:43 AM
Frequency and phase graph of the presence.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on April 05, 2018, 12:46:29 AM
In the meanwhile I will manage to add the 100K resistor in series to R17, so we'll see what happens.
Should this be not enough, I still have the U10 OP AMP and 4 caps (C56,C57,C48,C49) to replace.

But I think that a "step by step" approach would be the best.

I'll have a look to my other MP-1's tubes board before I do anything inside my main one.  :lol: :lol: :lol:
If there's a reason for everything, maybe that MP-1 with all its issues could be here for this purpose.

Hey, that's the fun of being part of this place!  :wave: :wave: :wave:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on April 05, 2018, 01:00:21 AM

@ Max, interesting results with loop send and headphone out with output off.  So the loop send is before the chorus (IIRC after the eq, MJMP did post the signal flow a while ago), the headphone out is after the chorus (as is stereo) but before main outs (I think, or what you did wouldn't work), the headphone out also has rudimentary filters to reduce top end (similar to a cab sim).  So if you have lowered your trim pots to minimum (means with MDRT the tube stage is running much hotter  >:D ), this could be overloading the eq or chorus input ? (a guess  :dunno: ).


Hey Rich, yes...internal trimpots have been set that way already by Phil when he modified my MP-1, due to new MDRT voltage I assume: OD1 and OD2 trimpots are set to their lower value and there's plenty of gain still... :headbanger:
What do you think could be overloading eq or chorus? By the way, chorus is 100% off on my "gainy" patches.

By the way, the more I think about the issue, the more I'm convinced that the squeal could be an internal oscillation somewhere between the output of the tubes board and the input of a next stage, probably due to an overload under certain conditions: MDRT gives higher voltage to tubes, tubes are running hotter (and that's f**king good!!!) and maybe the stronger signal coming from there could be too high for some next stage when I rise gain and eq up.
The issue seems to be related to final output level and this is the reason why MJMP suggested to replace U10 and C56,57,48,49 at first.
Then we had some test comparison with MikeB and Herby and find that similar mods lead to the same issue...and here we go with the idea of adding a resistor.

Let's go on and I'm sure we'll come to a solution, so that we can run our MP-1s hotter than Hell and enjoy the fabulous tones coming out from them thanks to MDRT and other mods.
Should be this the problem, MJMP's idea of adding that 100K resistor could be the solution.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on April 05, 2018, 04:12:03 AM
Hey MJMP, not quite sure how to interpret the graph, comparing phase and frequency (not sure I quite get it ?).  Could you draw us a diagram/schematic like the one on page 3 of the MP2 manual of the MP1 signal flow (I know you posted it in words but a picture would be nice)

Hey Max, the next stage after the tubes/ss is eq, the loop send/retrn is after that and then the chorus stage.  The chorus stage is always used as this is where the signal is split into pseudo stereo by inverting (180 deg) the signal into B.  If the chorus is IN it also applies very short delay (depth setting, more depth = more delay) to the B channel and rate (sweep modulation, varies the pitch (slightly) of B compared to A) between the 2 channels. So the eq stage could be overloaded at its input, and/or the chorus could be overloaded (depending on eq settings e.g. if you boost everything = more level).  However, I was intrigued by what you said about turning the main output to 0 making the squeal go away (and monitoring the signal elsewhere (loop send/phones out), this indicates (to me) something to do with the output section  :dunno: .
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on April 05, 2018, 05:13:46 AM
Hey Max, the next stage after the tubes/ss is eq, the loop send/retrn is after that and then the chorus stage.  The chorus stage is always used as this is where the signal is split into pseudo stereo by inverting (180 deg) the signal into B.  If the chorus is IN it also applies very short delay (depth setting, more depth = more delay) to the B channel and rate (sweep modulation, varies the pitch (slightly) of B compared to A) between the 2 channels. So the eq stage could be overloaded at its input, and/or the chorus could be overloaded (depending on eq settings e.g. if you boost everything = more level). 

 :thumb-up: :thumb-up: :thumb-up:

However, I was intrigued by what you said about turning the main output to 0 making the squeal go away (and monitoring the signal elsewhere (loop send/phones out), this indicates (to me) something to do with the output section.

Yes, I'm quite sure it's something there as well...and for the same reasons you said.

@MJMP: Phil, when you said that this squeal could be related to some too high voltage to digital pots....which digital pots were you talking about in the signal chain/path?  :bow:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on April 05, 2018, 07:21:42 AM
@R, this is the frequency response of just the presence section. As you can see it has a quite big range (but it's also a simple filter) and the center freq is around 6kHz.

@Ip, these are U13 (TC9176), as you can see in the schematic the output of the tubeboard goes straight into pin 3 of U13.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on April 05, 2018, 09:09:59 AM
@Ip, these are U13 (TC9176), as you can see in the schematic the output of the tubeboard goes straight into pin 3 of U13.

f*ck yes! Got it on the schema.
So..how the Output Level pot is related to U13?

Forgive the silly questions...but solutions to issues could arise from shred them in smaller pieces!  :lol:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on April 05, 2018, 09:28:33 AM
It's actually not directly related, this controls the master volume (which you can program).
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on April 13, 2018, 09:58:43 PM
Ok, so I turned down the output volume pot and the squeal went away.  I have been pretty busy and then got sick so I haven't been motivated to do another test of the thresholds.  I also haven't yet adjusted the trimpot.  More to come.  Got to sort out all my levels again by tomorrow for the jam.  Should be good.  I was able to play with OD1,OD2 and MV on 10 each.  Output pot was way down though.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on April 16, 2018, 08:52:13 AM
Ok, so I turned down the output volume pot and the squeal went away.  I have been pretty busy and then got sick so I haven't been motivated to do another test of the thresholds.  I also haven't yet adjusted the trimpot.  More to come.  Got to sort out all my levels again by tomorrow for the jam.  Should be good.  I was able to play with OD1,OD2 and MV on 10 each.  Output pot was way down though.

Hey Mike!
So...it looks we're on the same side of the road!  :lol:
Where can you set Output pot with OD1 and OD2 at 10.0???
I set OD1=OD2=7.5 and MV=5.5 and I can set the Output pot around halfway before the squeal starts...and a little over halfway if I decrease highs and presence...or ODs, of course.

By the way, I've the 100K resistors ready but I've been busy as well and then my welder broke 2 days ago and it needs to be repaired...or I need a new one...but this is NEW and f**king expensive!  :lol:

FYI, my internal trimpots for OD1 and OD2 gain are set to minimum (and there's a lot of gain anyway...).
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on May 02, 2018, 08:07:24 AM
f*ck.
As I wrote to MJMP, I've got my welder repaired...and now I'm struggling with resistors!

R17 is 430K but I can only find 470K resistors around...and putting too many resistors in series seems to be not a good idea, when you've to put them all together on the tubeboard...  :lol:

Stay tuned.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 02, 2018, 04:17:10 PM
Been a while.
I had a chance to examine the OD trim pots today. Both pots were set to about 60%. I'm assuming this is 'way' too hot. I'm going to run some tests this weekend. I'm going to start by setting both pots to 0% and see what happens.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on May 03, 2018, 02:21:44 AM
In the meanwhile, I've 2 560K resistors and MJMP confirmed that 560K is a good value to replace R17.  :headbanger:

About internal OD1 and OD2 trimpots, they are set to 0 already on my MP1 and:

1) there's plenty of gain anyway
2) the squeal issue is still present

As MikeB already did, another test on the third MP-1 with this issue could be a good thing.
Also verify what happens to the squeal with your high gain settings when lowering Output Level pot.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on May 03, 2018, 01:56:01 PM
 I haven't looked at my trim pots yet. But,  I have enjoyed playing with od1 and od2 on 10 by turning down the output volume.  :headbanger:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 03, 2018, 05:14:55 PM
Lowering the output volume does tame the beast quite a bit.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on May 04, 2018, 01:56:23 AM
Lowering the output volume does tame the beast quite a bit.

Try this:

1) set OD1 and OD2 trimpots to lower value
2) create a patch with (very) high gain settings
3) lower Ouput Level pot untile the Beast is 100% quiet

Does it work for you as well?  :lol:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Iperfungus on May 04, 2018, 01:56:52 AM
I haven't looked at my trim pots yet. But,  I have enjoyed playing with od1 and od2 on 10 by turning down the output volume.  :headbanger:

Me too!  :thumb-up:

But I'm going to replace R17 and see...  >:D
Furthermore, as soon as he will have some MDRT again, MJMP could help us more.

Where/how do you set Ouput volume pot with OD1 = OD2 = MG = 10.0???  :lol:
It should be around 9 'o clock or less....isn't it?
Or no more than that...
And how do you set the overall EQ?

Maybe we could agree about a test setting for our MP-1s and see if all of the units behave the same...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 08, 2018, 06:11:49 PM
Tested the MP1 with OD1 and OD2 trim pots all the way down. Squeal is gone, but I still have a lot of hiss at high gain past 6. Plenty of gain on tap. Turning the pots counter clockwise turns them down, correct? Any thoughts?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on May 09, 2018, 06:48:52 AM
I haven't looked at my trim pots yet. But,  I have enjoyed playing with od1 and od2 on 10 by turning down the output volume.  :headbanger:
But then turning up the TC GMaj2 outs to compensate,  Mike has gone back to Woodstock era, howls and squeals  :whoohoo!: how to tame all that gain... I love it, and good to hear (for me).
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Soloist on May 09, 2018, 09:06:08 AM
A couple of notes on the G Major 2:
To tame the hiss on heavy distorted tones use the hard gate. For medium distortion use the soft gate. Also if you haven't tried this yet go into the g majors i/o and switch the input ring between pro to consumer, it changes the input sensativity. I believe pro is +4 db and consumer is -10 db. Also change the output ring consumer should be 20 db and pro should be 8 db. This gives an equal output level. :thumb-up:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 09, 2018, 09:15:57 AM
This conversation has completely lost me. What is Gmag2? There is no gate on the MP1. I'm totally confused...
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Soloist on May 09, 2018, 01:42:07 PM
G major 2 is a multi effects rack unit made by T.C. Electronics. Sorry didn't mean to lose you. My reply was for Richard.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MikeB on May 09, 2018, 01:56:38 PM
Hi Herby,
I use a  tc-electronic g major 2 and Max uses a  g major.  It has an input level that I used to need to turn down to cope with the output from the mp1.   Now that I have reduced the output of the mp1,  I can increase the input level on the gmajor2.   With both ODs on 10, the feedback is wild.  I'm going to have to try using the gate on the g major2.   

I haven't yet looked at my trim pots, but there is no opportunity to hear a hiss at these levels because the feedback is drowning that right out. When I get a chance, I'll do some more experimentation.
Mike
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 09, 2018, 02:07:00 PM
Ah, thanks for the details Mike. I'm running straight into a Mesa 2 fifty. I'm going to hook up my 1101 and see what the gate can do for me.

@Soloist : If I'd have looked at your sig I would have figured it out   :facepalm:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Soloist on May 09, 2018, 04:23:06 PM
Hi Herby, I tried the 1101 with the mp1. I didn't like it, tone sucks horribly.  I also run into a 50/50 it sounds awesome.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 09, 2018, 06:43:37 PM
How did you run it? How did you set it up?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Soloist on May 10, 2018, 01:38:15 AM
I tried both set ups, #6 and #7 in the manual. Both 4 cable methods. The effects sounded good but it smoothers the tone of the mp1. I found with the Mp1 it needs an effects unit like the g major2 or g force or something similar to really make it shine.  A BBE sonic maximizer just before the 50/50 also helps if your looking for that 80's tone. :metal:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on May 10, 2018, 07:31:53 AM
Hey Herbyguitar, so to be clear that you know what 4 cable method is.. it just means connecting a stero multi effects in between the MP1 and power amp in series, ie MP 1 A/B out > Fx L/R input, Fx L/R outputs > amp L/R inputs > 2 x cabs.  So four patch cables used to connect MP1 to Fx and Fx to amp = 4 CM.

What Soloist was saying to me was, ok if you have to radically turn down your MP1 outs (because of the issues we are discussing, and not what you would normaly need to do BTW), you can compensate for the gain differences with the TC GMaj / GMaj2 (as for both he and Mike they have that Fx unit in between 4CM to amp) by making the GMaj/2 input sensitivity set to consumer rather than pro.  Consumer is more sensitive (excpects a lower level than pro gear which oprates on a higher voltage input signal). So by doing this change, the TC GMaj/2 adds gain so it can take the "radically reduced" MP1 signal and boost it for the rest of the chain.

However, while this approach works (given the oselation issues etc) it's bad gain structure.  But as an asside, Mike has been able to run his ODs' really high (inherant instability, squeals, wild feedback etc and how I learnt to play (and to the extent you can, contol) many years ago, 101 rock guitar IMHO).

But we still havn't solved the MP1 issues.. :facepalm:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 10, 2018, 07:27:07 PM
Well. No more squeal. My only problem now is hiss (white noise). It's pretty substantial. It increases with volume and gain. With these mods I was expecting it to be quieter but it's not. There's more hiss now than there was before the mods, but all other noise and hum are gone. I have all new tubes. What will cause this 'hiss' and how do I get it down to an acceptable level?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on May 11, 2018, 05:38:41 AM
Hey Herby, well hiss can be caused by lots of things, given all the mods you've done it's unlikely to be the MP1  :dunno: but hard to say for sure.. You play a strat ?, with single coil PUs ?? they pick up allot of noise eg from fluorescent lights, even your wifi (if it's on and in range), and power can also be an issue..  When you go high gain it also boosts the noise.  But it may be as simple as your guitar output jack or a lead(s).  Go back to really simple eg Guitar > MP1 > poweramp > cabs, get that sorted so the hiss isn't an issue and then bring in Fx etc if all is good.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: Soloist on May 11, 2018, 08:02:14 AM
Hey Herbie, like Richard was saying the hiss could be from alot of different stuff. Are you using a power conditioner?  It could be something as simple as a poorly shielded instrument cable or patch cable.

Could also be an issue with the 50/50. Mine was introducing a constant crackle, had it gone thru, replaced a few resistors and it's like new. :whoohoo!:

Usually the pickups are the culprit. Some are just noisey some are just that sensative. Pick up a used noise gate for cheap. I use one after guitar before any thing else just for noisey/sensative pick ups. :thumb-up:
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on May 11, 2018, 08:16:05 AM
Did you measure this noise with the guitar plugged in?
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on May 11, 2018, 03:54:03 PM
I'm running simple. MP1 to amp. All chords are good and top quality. Guitar is good with no problems. Have 2 other amp setups to compare with. Have several other guitars to compare with. Some are SC, some have HBs. With signal I get a loud hiss. Without signal I get a midrange hum.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: rnolan on May 11, 2018, 10:19:14 PM
Have you tried just MP1 on its own with headphones from the MP1s headphone out ? Every thing else turned off.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: MarshallJMP on May 14, 2018, 09:23:49 AM
To measure the noise generated by the MP-1 itself you need to unplug the input.
Title: Re: Herby's attemt @ SS Mod, Noise Mod, MDRT Mod
Post by: herbyguitar on December 10, 2018, 01:27:32 PM
I'm trying to reach MarshallJMP about looking at my MP1. Is the offer still good or did you change your mind?