ADA Depot - A Forum To Support Users of ADA Amplification Gear

ADA Preamps => Original MP-1 => Topic started by: davidfugler on October 14, 2018, 03:40:22 AM

Title: my new mp1 sounds like dudu
Post by: davidfugler on October 14, 2018, 03:40:22 AM
 Hi, I'm new to this forum. Thank God I found it. My mp2 has the motorboat problem, so I got an mp1 for a backup, and sent out my mp2 to get worked on. I listened to a number of clips of mp1's that sounded fantastic, but this mp1 sounds like a 30 dollar peice or garbage. the eq is the problem all 4 points are so narrow I had to zero out bass and mid, and pull down treble and presence, and use a graphic eq to boost up lower mids and bass, way up, to get anything close to a usable sound
I have searched this forum for hours and hours, but I'm not sure which mod would best address this thin, treble heavy, pocket radio from the 60s sound. Or, throw this mp1 in the trash and try getting another one, and hope for better luck....Help.
Title: Re: my new mp1 sounds like dudu
Post by: rnolan on October 15, 2018, 12:35:10 AM
Hey david, welcome to the depot  :wave: , and we are happy to help as much as we can :thumb-up: .There are some posts about the MP2 motorboating if you dig around.  It was quite a while ago it came up IIRC This post (http://adadepot.com/index.php?topic=177.msg820#msg820) is related to it.  You can do the MP2 noise mod, replace 21 caps and a resistor, IMO the resistor (R913  :dunno: ) is the most important (if it needs replacing), if you get 190v or just under (around 187v) at the test point then it doesn't.  The problem comes when the test point voltage exceeds 190v.  MJMP puts a kit together with all the components you need for the mod (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm).The MP1 should sound good out of the box, factory patch 1 (Marshall) should sound very usable, I used it as a starting point for most of my MP1 patches.  So I'd try reloading the factory patches:LOAD ALL 69 PRESETS:
1. Press the STORE button. lt will light.
2. Press the BANK button and while holding the BANK button down press the number 1 button.
3. The display will read "Presets Loaded" When the display returns to a program number, all 69 factory presets have, been restored.
If patch 1 still doesn't sound good, it could be tubes, always worth putting in some new ones anyway.
I suggest you start 2 new topics one for your MP2 and one for your MP1 either in their respective areas or in the Lets get technical and we'll work through the issues with you  :thumb-up:
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on October 15, 2018, 04:35:02 PM
thank you
Title: Re: my new mp1 sounds like dudu
Post by: Chamai on October 19, 2018, 01:53:34 AM
what power amp and speakers are you using?
im rocking a marshall 9005 power amp with g12t75 speakers. my mp1 sounds freaken massive.

Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on October 22, 2018, 04:39:14 PM
my mp2 sounds massive through my hafler and EV loaded one twelve cabs. The mp1 with factory preset 1, various new tubes sounds terrible.I even took the new Mullards out of the mp2, used those, and no better. tiny and tinny. Gotta be something wrong with it.
Title: Re: my new mp1 sounds like dudu
Post by: rnolan on October 23, 2018, 01:59:56 AM
Hey David, I agree, something isn't quite right, a pair of known good Mullards and factory patch 1 should sound decent, well better than decent.  Tiny and Tinny sounds like the signal isn't getting through properly. My first guess is the input jack (it gets the most ware) and these are old units.  But it could be a number of things, we'll have to step through them all a try to find the issue. 
1. Do you get any leds flashing when you play ? this will indicate if there is decent signal in the various circuits.  They should flash or even stay lit or go red when you turn up OD1, OD2 and Master on a patch. If no leds flashing then input jack may be the issue.  It's worth giving it a clean with some decent contact cleaner regardless.  Can you take some pics of the inside (take the lid off) and post them/attach them (keep them around 1.5MB or they wont attach), this will show us a bunch of stuff about the version (e.g. the later version MP1 input jack is relatively easy to replace, early version MP1 not so easy and better to do the rear jack mod).2. If you have flashing leds, take the signal from Fx loop send to amp (there should always be good signal here and will help rule in/out where problem is likely to be)3. While you have the top off for pics, give the output vol pot a good clean with contact cleaner (it may be the culprit) BTW is it scratchy ??).It's also worth taking off the bottom cover (easy, like the top except with the top you have to undo the front center screw) and take some pics, this will show if it's been worked on, maybe it's a failed mod someone attempted (not uncommon).Check out MikeBs post (http://adadepot.com/index.php?topic=2241.0) for the various pics that help.
Title: Re: my new mp1 sounds like dudu
Post by: MarshallJMP on October 23, 2018, 10:01:26 AM
The hafler, is that a power amp or a true guitar amp?
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on October 25, 2018, 04:48:16 PM
thanks, I'll do these suggestions. The Hafler is a ss stereo power amp. Been using that since my b200s died back in 1995. It still sounds good with the mp2, but I'm also trying to find a good tube power amp. peavy 50/50 is too midrange heavy for my taste, and a carvin tube 100 I just got is too top heavy, but maybe mod able somehow. I put a post in the non ada amp section about the tube 100, that I also need help with.
Title: Re: my new mp1 sounds like dudu
Post by: Chamai on October 26, 2018, 01:23:17 AM
Tube power more makes a hue difference. Try going for a mesa power amp instead. 6l6 sounds nice and thick with less midrange.

The secret with great distortion is adding an equal pedal up front. Reverse smile face on the eq pedal and put the levels and it. Cutting bass and treble and boosting mids gives the distortion more clarity. You can also up the bass on your mp1 without the bass sounding flubby. Think mesa amps. A lot of people cut bass and upping the bass using the onboard eq instead. 
Title: Re: my new mp1 sounds like dudu
Post by: MarshallJMP on October 26, 2018, 08:59:27 AM
Ah ok so the amp is good.
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on October 27, 2018, 06:00:38 PM
now I get to tell you how much of an idiot I am. I didn't know what the switch was for on the top of the unit. Now I do. Problem solved. I had it in instrument position. Now it's got bottom end. Sorry guys. Shoot me.
Title: Re: my new mp1 sounds like dudu
Post by: MarshallJMP on October 27, 2018, 10:38:54 PM
Ok great you solved it, didn't know that that would affect your sound so much.
Title: Re: my new mp1 sounds like dudu
Post by: rnolan on October 27, 2018, 10:47:23 PM
Ok great you solved it, didn't know that that would affect your sound so much.
+1  :thumb-up: ,
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on October 28, 2018, 09:24:15 AM
still a little thin on top
Title: Re: my new mp1 sounds like dudu
Post by: MarshallJMP on October 29, 2018, 01:28:19 PM
Looks like an early 1988 model.
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on October 31, 2018, 04:33:06 PM
although it's much louder, the bass sounds centered at around maybe 400 hz or higher. the treble and presence both sound very narrow. picture a graphic eq with 5k pushed up quite a bit and maybe 6.5 k pushed up the same. that's with both at zero. if you turn either, or both up it just sounds like fingernails on chalkboard. not at all what i hear when i listen to mp1 clips online. does it look stock? or modded?
Title: Re: my new mp1 sounds like dudu
Post by: MarshallJMP on November 02, 2018, 09:54:41 AM
Looks stock to me.
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on December 03, 2018, 03:01:22 PM
any idea where i can get a power switch and input jack?
Title: Re: my new mp1 sounds like dudu
Post by: rnolan on December 03, 2018, 09:58:20 PM
Looks like a good candidate to do the rear jack mod (and replace both input jacks) http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm.MJMP can probably help you with a power switch also.
Title: Re: my new mp1 sounds like dudu
Post by: MarshallJMP on December 04, 2018, 03:29:35 AM
Why do you need a new power switch? is something wrong with it?
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on December 04, 2018, 03:04:27 PM
I have to switch it on 2 or 3 times to get it on, quite often.
Title: Re: my new mp1 sounds like dudu
Post by: MarshallJMP on December 05, 2018, 02:44:17 AM
That's not a switch problem, looks more like a power supply problem.
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on December 05, 2018, 03:26:57 PM
think that could have anything to do with the thin sound? I was thinking of getting your transformer upgrade. what do you suggest I do?
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on December 05, 2018, 03:57:55 PM
if I do the rear switch mod, someone said the earlier models are difficult to change the front jack. If it's a 1988 what do you suggest? My soldering skills are pretty questionable, at best. Also, the far left (input) LED just barely flickers, with both gains at 10. Sorry if I'm a scatterbrain.
Title: Re: my new mp1 sounds like dudu
Post by: rnolan on December 06, 2018, 02:40:02 AM
Having watched/helped Mike do the rear jack mod it's not the front jack that is difficult as you change it to a normal jack (as used in the later models) rather than the PCB mounted jack socket.  The rear socket is a bit harder as you have to bend things open a bit to get the old one out (IIRC) (which is the normal/easiest/least time consuming way and what Mike did) OR undo all the rear jacks knobs etc to completely disassemble the back plate.  However, once dissembled the rest is easy, so this way takes more time.  If you look at the pic (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm), the right hand jack (normal style- pre soldered) is the front jack replacement, the other one (black plastic) is for the rear.


Title: Re: my new mp1 sounds like dudu
Post by: Systematic Chaos on December 06, 2018, 03:23:51 PM
think that could have anything to do with the thin sound? I was thinking of getting your transformer upgrade. what do you suggest I do?

Let me suggest a methodical approach here...

I'm with MJMP suspecting something in the PSU being the culprit for the power-up issues. Low and thin gain could be the old front jack and/or Diode D16 as well as some old dried out caps having gone far off specs.

To address all of the above:
- do the Noise Mod
- do the rear jack conversion Mod
- do the Battery Mod

That should get you back on track. Concerning the transformer: some prefer the smooth compressed sound of the original tranny, some prefer the added clarity of the MDRT.
If you get it up and running again with the 3 mods I mentionend you can still decide if you like what you're having or if you wanna add the MDRT.

Soldering is no witchcraft. The hardest/most difficult part soldering-wise of the mods I mentioned above is changing the U4 OpAmp (IMHO).
If you're uncertain you can do it, gather all parts for the mods and take it to an amp repair guy or (if you still have them in your neck of the woods) an old TV repair shop.
It's just swapping some resistors and caps and an OpAmp for newer better spec'd/higher quality parts. Desolder the old parts carefully while paying attention not to lift/burn any traces (less heat on the soldering iron is more!!). Clean everything nice and tidy with desoldering braid and PCB/Solder Flux cleaner, put in the new parts, make sure you get clean solder joints. Clean everything with Solder Flux cleaner again after the soldering job and you're golden.
Title: Re: my new mp1 sounds like dudu
Post by: davidfugler on December 08, 2018, 04:24:33 AM
Thankyou. I will do those mods and see what happens. :)