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Let's Get Technical => Schematics & Modifications (mods) => Topic started by: rabidgerry on December 15, 2014, 04:06:37 AM

Title: SS Gain Mod for MP1
Post by: rabidgerry on December 15, 2014, 04:06:37 AM
Thinking about doing this mod but I have a few questions about this:

bypassing the Input FET Buffer Circuit

I would like to do this mod, and basically maintain the ability to plug pedals and passive pickup guitars into the input.  Is it possible?

Is it a good idea to do the noise mod at the same time as this?

And how much more gain do I get?  Is this a mod anyone has done on here and enjoys?

Title: Re: SS Gain Mod for MP1
Post by: rnolan on December 15, 2014, 05:15:55 AM
Hey RG, the link doesn't take you anywhere (probably a good thin LOL) so not sure what your asking yet. From my understanding, any of the MP1 mods will maintain the ability to plug the guit direct (IMHO the best choice) or put pedal things in front (one reason I went rack was to get rid of all the stuff in front that needed power supplies etc), now I have a midi pedal, phantom powered.
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 15, 2014, 07:01:06 AM
Hey RG, the link doesn't take you anywhere (probably a good thin LOL) so not sure what your asking yet. From my understanding, any of the MP1 mods will maintain the ability to plug the guit direct (IMHO the best choice) or put pedal things in front (one reason I went rack was to get rid of all the stuff in front that needed power supplies etc), now I have a midi pedal, phantom powered.

it's not a link man  :D  I dunno why I decided to bold it and underline.

What I am asking is if I leave the FET section steps 8 and 9 will it sound shite?  or is it worth doing the Mod at all since I wish to have the ability to use pedals as well as maintain ability to plug a massive guitar in?  I got a little confused with the guide since it seems to favour the FET bypass option.






Title: Re: SS Gain Mod for MP1
Post by: Systematic Chaos on December 15, 2014, 07:06:46 AM
You might wanna contact MJMP....these instructions are a bit older and the Stock Gain mod got some more updates/mods since then (new revision of stock gain mod -> MP-1 Super-Stock
MJMP offers it also as completely new modded tubeboards with far superior components (higher quality caps, resistors and tube sockets).

If you´re already in for the MDRT upgrade, do it all together with the new revision of the noise mod as well.
Title: Re: SS Gain Mod for MP1
Post by: MarshallJMP on December 15, 2014, 01:04:54 PM
Don't bypass it,it has no use at all.
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 15, 2014, 01:30:58 PM
You might wanna contact MJMP....these instructions are a bit older and the Stock Gain mod got some more updates/mods since then (new revision of stock gain mod -> MP-1 Super-Stock
MJMP offers it also as completely new modded tubeboards with far superior components (higher quality caps, resistors and tube sockets).

If you´re already in for the MDRT upgrade, do it all together with the new revision of the noise mod as well.

I had asked him in an email about FET Buffer.

He has responded here

Don't bypass it,it has no use at all.

ok I wont bypass it, thanks.

Does anyone like this mod?  Only seems like 3TM gets mentioned about here, and occasionally the MOD 3.666.

I have 3TM Covered as I'm buying the one up for sale in the for sale section.  I just wanted to make the other mp1 different, and SS seems different.

Worth doing the noise mod at the same time then?
Title: Re: SS Gain Mod for MP1
Post by: MarshallJMP on December 15, 2014, 02:02:32 PM
Ask MikeB,i sold him a SS kit a few weeks ago.
Title: Re: SS Gain Mod for MP1
Post by: MikeB on December 15, 2014, 10:13:42 PM
Ok, so here's my two cents worth....
My understanding is that the SS mod by itself is not a gain mod.  (MJMP correct me if I'm wrong).  I asked specifically for one without the gain mod included because I want to keep my clean tones clean.

A bit of history first...
My mp1 started blowing tubes and so i took the plunge that it was something on the tube board and bought a replacement from MJMP's mod shop.  I did include the noise mod, so he sent me a beautiful new tube board and a whole slew of bits and pieces to replace on the main board. 

When I put it all back together it was a different beast.  I was getting waaay more gain and some high pitched whistling on some of the patches.  I can only guess that the old tube board was fading gradually over time and that my patches were creeping up to compensate.  I most likely didn't notice this because I went through a long period playing mostly my Marshall.  I finally got around to getting some rack effects gear (TC g-major 2) and then re-did all my patches anyway.  Perhaps because of this I didn't notice the gradual loss of gain.  So, once it was all fixed, it blew me away.  I actually had a patch with OD1 and OD2 both on 10 and I wasn't getting any noise at all!! 

Needless to say, the 10, 10 patch is now extremely noisy and is the one that has the high pitched whistling.  In fact, that patch no longer exists.  I have pegged them all back a bit.  And this is without including the gain mod.  I have more noise now after having done the noise mod than I ever did before, but that would be because of the lost/found gain.

So, in answer to your question, I can't really provide you with a before and after snapshot of the SS mod.  I can tell you that it sounds great after, but I am now thinking that I am going to have to pick up a noise gate.

I've just re-read all of this and realised that I have taken up lots of space not saying much at all.  Sorry I can't really help you.
It has, however, helped me. This is like therapy.  I feel great.  I think I just need to get it all out.  Thanks!!
Title: Re: SS Gain Mod for MP1
Post by: Systematic Chaos on December 16, 2014, 12:28:55 AM
The Super Stock aka Stock Gain Mod is not that different than the original....which is its intention. Offer more gain (dooooh) while retaining the characteristic MP-1 tone. (BTW, MJMP pls correct me if im wrong.......).
If you´re in for sth "different" I´d recommend the 3.666 or the 3.1 (MJMPs new revision incl new tube board).
MDRT is a vast improvement and I can highly recommend that! As is the new rev of the noise mod.
Also changimg the OD OpAmp to a BurrBrown OPA2604. It adds a tad bit more dynamics and tubey-like warmth....

Just my 2 €-cents and findings I´ve had with my MP-1s  :thumb-up:

BTW, the rev of the 3.1 with the MDRT MJMP did for me in 2009 took it to a more SLO'ish/CAE 3+ character....I liked it a lot!
And the Clean Tube got better as well ;-)
Title: Re: SS Gain Mod for MP1
Post by: MarshallJMP on December 16, 2014, 05:19:47 AM
Well the SS mod can be orderd as a standard gain and as an increased gain board.But i usually sell the standard ones because in 90% of the cases these have enough gain unless you have very low output PU's.The SS mod is almost identical to the original except for about 10 caps that have a different value,mostly for tone and noise changes.It makes the tone a bit tighter and brings the noise down compared to the original board but retains the original sound.
Title: Re: SS Gain Mod for MP1
Post by: rnolan on December 16, 2014, 05:35:40 AM
Was playing through MikeB's MP1 on Sunday, so this is new tube board, noise mod no gain change (is my understanding ? ), anyway sounds good but he has to keep his master vol down for 10/10 patches, so he's looking into Decimator/Hush or similar (probably Decimator floor pedal in loop is our current thinking). I was using my new JPP LP  >:D , man was the neck PU creamy or what... :thumb-up:
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 16, 2014, 06:59:05 AM
The Super Stock aka Stock Gain Mod is not that different than the original....which is its intention. Offer more gain (dooooh) while retaining the characteristic MP-1 tone. (BTW, MJMP pls correct me if im wrong.......).
If you´re in for sth "different" I´d recommend the 3.666 or the 3.1 (MJMPs new revision incl new tube board).
MDRT is a vast improvement and I can highly recommend that! As is the new rev of the noise mod.
Also changimg the OD OpAmp to a BurrBrown OPA2604. It adds a tad bit more dynamics and tubey-like warmth....

Just my 2 €-cents and findings I´ve had with my MP-1s  :thumb-up:

BTW, the rev of the 3.1 with the MDRT MJMP did for me in 2009 took it to a more SLO'ish/CAE 3+ character....I liked it a lot!
And the Clean Tube got better as well ;-)

Not sure I fancy those mods.  I like the SS as it's standard tone but bit more TURBO.  I also quite like the idea of doing it myself along with the revised noise mod.

If I had details off all the parts I could do it.

What parts on the main board are worth replacing and what are the improvements?

Is it worth replacing stuff like this with old gear?  I have another unit that might benefit from caps and resistor replacement.
Title: Re: SS Gain Mod for MP1
Post by: rnolan on December 16, 2014, 07:18:45 AM
Mike just got all the bits from MJMP who also built him the tube board (nice MJMP BTW  :thumb-up: ) coz Mike wanted it without gain mods, just noise mods.
(Is it worth replacing stuff like this with old gear), I think so, if there was something modern that was as good or better, I'd be happy to recommend it, nothing even close IMHO yet. Also taking advantage of better components either equals or exceeds the original circuit, but for me the main game is keeping it alive and dependable.
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 16, 2014, 08:10:36 AM
Also taking advantage of better components either equals or exceeds the original circuit, but for me the main game is keeping it alive and dependable.


This is what I meant, as it might be a good idea to replace other parts along the way to keep the MP1 ready to rock.  I was hoping I could do my Boss GL100 as well.  I wouldn't know where to begin with what to replace though.  I know I need to do a input socket on it as it's intermittent.  I like the unit and want to keep it.
Title: Re: SS Gain Mod for MP1
Post by: rnolan on December 17, 2014, 07:54:52 AM
The MP1/2 MB1 have been so rock solid, but as things age... Sockets are easy(ish) though, although some of the ADA sockets don't earth to case to alleviate earth loops (e.g. B200s outs). Upside is MJMP has some replacements on hand.
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 18, 2014, 05:22:21 AM
So where can I get a list of parts to do the SS revised mod myself?  Are their guids about on how to do this?

I could do the one on here already which would take like 5mins!!

I'd rather do the revised one where I replace the caps with orange drops ect.  I can that stuff easily.
Title: Re: SS Gain Mod for MP1
Post by: Systematic Chaos on December 18, 2014, 05:48:36 AM
I'd recommend Orange Drop 716P, high-qual Panasonic Caps and Metal-Oxide resistors for the tubeboard. New Belton Micalex tube sockets will also go a long way....
F&T Filter Caps for the PSU.....
When you're at it, replace U4 with a BurrBrown OPA2604, also put a socket in there first....
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 18, 2014, 06:26:25 AM
Be prepared for more questions.

Is there any harm in doing this gradually?  Like I might do the tubeboard on it's own.

This will sound really silly but hey I'm no electrically qualified boffin - how do I obtain the values? Will it say on everything?
Title: Re: SS Gain Mod for MP1
Post by: rnolan on December 18, 2014, 07:09:06 AM
Hey RG, bit's of it will be a bit fiddly, others not so bad, depends a bit on how you go about it I suspect. Yes lots of good oil on how (MJMP  :bow: ). If you did it bit by bit, my take is that would be fine, there may be however, things that need to happen together (MJMP will know) but I wouldn't have thought many if any..  E.g. you replace a cap with an orange drop, cool so you replaced a cap.... If you see what I mean... It just works better...
Title: Re: SS Gain Mod for MP1
Post by: trader144 on December 20, 2014, 06:48:25 AM
Be prepared for more questions.

Is there any harm in doing this gradually?  Like I might do the tubeboard on it's own.

This will sound really silly but hey I'm no electrically qualified boffin - how do I obtain the values? Will it say on everything?

You can but you will find its a major time killer to do it in stages. Also a pain to source the parts IMO get a package of component parts and instructions from someone who sells mods like MJMP and do it all at once. They have done alot of the work and part testing for you.

Read all the way thru before staring and get all the tools in advance. Answer all of your questions before you begin. Don't skimp or shortcut. Take your time and do a quality job so your unit will last thru a beating and won't go out in stage. Practice desoldering and soldering some other circuit board else if u need to.
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 20, 2014, 03:11:24 PM
Be prepared for more questions.

Is there any harm in doing this gradually?  Like I might do the tubeboard on it's own.

This will sound really silly but hey I'm no electrically qualified boffin - how do I obtain the values? Will it say on everything?

You can but you will find its a major time killer to do it in stages. Also a pain to source the parts IMO get a package of component parts and instructions from someone who sells mods like MJMP and do it all at once. They have done alot of the work and part testing for you.

Read all the way thru before staring and get all the tools in advance. Answer all of your questions before you begin. Don't skimp or shortcut. Take your time and do a quality job so your unit will last thru a beating and won't go out in stage. Practice desoldering and soldering some other circuit board else if u need to.

The original mod is a five min job.  Since I have ditched that idea and want the "revised" ss mod I'm going to need more parts soooooooooooooooooooooooooooooooo....................

You are right Trader144 and Richard.  Kit would be best.  Have already been in touch with MJMP to ask can I just buy parts and make it all myself.  I know nothing about schematics though and other tech stuff but I can modify and do the practical side no probs.
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 20, 2014, 03:13:46 PM
Well the SS mod can be orderd as a standard gain and as an increased gain board.But i usually sell the standard ones because in 90% of the cases these have enough gain unless you have very low output PU's.The SS mod is almost identical to the original except for about 10 caps that have a different value,mostly for tone and noise changes.It makes the tone a bit tighter and brings the noise down compared to the original board but retains the original sound.

Yes I want increased gain version, but only if is usable   8)
Title: Re: SS Gain Mod for MP1
Post by: trader144 on December 20, 2014, 06:38:07 PM

Yes I want increased gain version, but only if is usable   8)

Just thought I would mention: gain is not distortion so increased gain will always be useable. Increased distortion however may not be useable. 
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 21, 2014, 02:44:59 AM
No more distortion?    :'(

shit


 :lol:
Title: Re: SS Gain Mod for MP1
Post by: rnolan on December 21, 2014, 05:06:39 AM
Hey RG, my understanding of the mods is to increase distortion  (partly by increasing gain/vol in parts of the tube circuit). There's the overall gain structure (between various components (in the MP1 (preamp) circuits and other gadgets in the audio chain), which need to match BTW), and also the gain within each bit/component/circuit (so the gain mods are more about the MP1 tube circuit I think). So in MP1/2 you have 2 twin triode tubes, each triode is a gain stage and is driven by what comes before it, increasing what comes before it in some cases (if you turn it up  >:D ) causes clipping of the wave/signal, the nice thing about tubes is when you do that to any of the triodes, it produces predominantly even harmonic distortion (which us Guit players like  >:D ), took many years to develop SS circuits that came near to this sound/characteristic (and I would argue they're not here yet LOL).
So don't despair, the mods (particularly 3TM (i.e. 2 more triodes to drive hard!!)) are to increase gain in the tube stages and thus add more distortion/clipping
Title: Re: SS Gain Mod for MP1
Post by: trader144 on December 21, 2014, 12:07:23 PM
Rabidgerry

I think we should be asking what sound you want out of your MP-1 (what type of bands)?
Didn't see anything specific in your other posts.

David
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 21, 2014, 12:25:02 PM
Rabidgerry

I think we should be asking what sound you want out of your MP-1 (what type of bands)?
Didn't see anything specific in your other posts.

David

Hey David, go look at the "what are you listening to this week" thread in rant's and raves  :)  plenty of indication what I like on there........................isn't that right MJMP?  :metal:
Title: Re: SS Gain Mod for MP1
Post by: trader144 on December 21, 2014, 02:19:19 PM
Got it.
Did you try a distortion pedal? Just wondering about your experience.
Title: Re: SS Gain Mod for MP1
Post by: rabidgerry on December 22, 2014, 05:25:18 AM
Oh yeah, I have.  Which is why bought a 3tm mp1 to cover that bass.  The whole reason I want the SS is just to supe up my other MP1 rather than have to MP1s the same.  Also just to give it a general overhaul internally (mind you the mp1 in question I think sounds amazing even with the rubbish no name tubes in there!! compared to another one I just sold)
Title: Re: SS Gain Mod for MP1
Post by: feline guitars on August 11, 2016, 05:54:04 PM
Just updated my MP1 that already has the SS Mod with the MDRT and I have to confess that these two mods are both worth it
The MDRT in particular is just what the doctor ordered.
I suddenly have very decent bass - not overpowering or flubby , but just right

The unit is now a great hard-rocking preamp and maybe one of the best sounding MP1s I've heard, and I've owned many MP1s since early 1988 (crikey that's 28 years!)

The gain levels that I would have to dial up to 10 before the SS Mod I now get before 7, and I find that I rarely need to have the gain pushed so hard.
The MDRT has given a whole lot more authority to the sounds..it's clearer because there is enough juice for the bass notes to be reproduced clearly