ADA Depot - A Forum To Support Users of ADA Amplification Gear
ADA Preamps => MP-2 => Topic started by: kawai2g4b on November 17, 2013, 09:54:35 PM
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Hey, I'm a recent convert to ADA equipment. I purchased an MP2 about a month ago off Ebay and upon firing it up, I noticed that the wah, when activated, does not sweep. In every setting, be it with the pedal or on the auto wah setting, I get a fixed wah tone when engaged. I even programmed the pedal to trigger the wah effect on at different points in its sweep. Before the triggering point, I get the normal signal. When past the point, I get the fixed wah. Is there anybody in here with any experience with such or problem or has the knowhow to how to approach a repair. I do have a local repair tech with experience on ADA racks but some extra guidance would do me well.
:dunno:
Thanks in advance!
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Marshall JMP may be able to help with tech aspect, I've always used my wah on triggered so it activates on each pluck. I only got one pedal (and the quad switch) with my MXC which I assign to Master Vol. so I've never used it as a "normal" wah as such. You could restore factory defaults just to make sure it's not some issue with pedal assignments or other wah settings. I'll have a fiddle with mine and see if I can discover anything else that may help.
Cheers Richard
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Yeah rnolan, I am running the same setup you have...through the MXC, Continuous Controller, and pedal, though I have two of them to run volume and wah. I reprogrammed the wah from pedal, to triggered and every which way possible (even when triggered halfway up the pedal) but the filter stays in the same position...its like it goes to instant Clapton woman tone, but in a bad way. Im glad the programming works as it should, but this is the only glitch in the entire preamp, and it might just be a loose connection (i'm a bit electronically challenged). It came like this when I unpacked it from an ebay purchase. Is seems as though I got fleeced for $250 plus potential repair costs but the guy incuded all the pedal gear along with it so maybe not so much. I'll try to get a hold of Marshall JMP for his opinion. Also, there is a rack mod tech at this link in Houston, near where I am, that I will go to for repair/modding:
http://www.thetonedoctor.com/default.html
http://www.thetonedoctor.com/Price-List-Shop-Online.html
BTW, anybody in the forums familiar with this guy?
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Well i have read your post but i must say i never encounterd such a problem with the mp-2.But what you could try is setting trimpot TR202 to a different position (but remember the original setting in case this doesn't help).This trimpot is part of the sweep circuit,so try it out.
Another thing could be U216,this is a vactrol (light depended potentiometer) and thirt option the opamps U205 and U207 (OPA2604AP),these get very hot and sometimes they fail (a known issue in mp-2's).These are easy to replace because they are in a ic socket.
So try these out,if it doesn't help we need to do some measurements.But that's for later.
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$250 with all the pedals is a good deal I recon (not that I'm checking MP2 prices that often). I paid $700 AUD for an MP2 for a friend. That included shipping (Hong Kong to Australia) but with one pedal and one quad switch. I also bought another MP2 from him for my studio as he said it was a bit intermittent and crashed sometimes, that cost $200 AUD with no pedals but included a Midiverb 4. I think I paid AUD $2500 ish for my first (new) MP2 when it first came to Australia.
While (if) you pull the lid off you should check the EPROM version and if it's not the last one made (v1.41) buy the upgraded EPROM from MJMP (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm), it's easy to fit. Main improvement that I noticed with it was faster program changes. Your tech will probably need the schematics which you also can get from MJMP's site. I have the basic one that was available on the old depot. If you PM me your email address I'll send you what I have. Do you have the MP2 user manual ? That "may" shed some light on the wah issue ?
Cheers Richard
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Once again MashallJMP, thank you for the input. I'm not the best with a soldering iron, much less with a pcb, but I'm going to relay that information to the local rack equipment tech when I take it there soon. Just like the Mb-1, I will keep you updated as soon as it gets out of the shop. O0
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Damn, rnolan, please forgive me on the "fleeced" quote. :facepalm:
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Not that forgiveness was required, but forgiven :thumb-up:. I suspect the more you use the MP2 the more you'll like it. IMHO it's the best guitar preamp ever made. My live rig MP2 has been solid for more that 25 years of gigging and is still going strong. The display is starting to fade (as are my eyes :-) ) a bit so I may replace it sometime. The only issue I've ever had with it is it's not fond of generators, makes it crash. As we rehearse in the bush with a genny, I bought a 1KVA UPS to isolate my rig from the genny's ups and downs.
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I'll say. that's cool that you can go out into the back country with a generator to practice. Over here, the only way to practice at full blast is to know someone with a barn on their property, and that is tough to find in the city. I finally got a power conditioner the other day, so the variances shouldn't be a concern for me any more.
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Yeah, we're lucky. One of the guys I jam with built a nice (fairly rustic) place in the bush, not to far off the main road. He's been living there for years. So good not to have to worry about volume and not be in some dark windowless room that you have to pay to use.
Any luck with the user guide ? Hopefully it helps. You can do quite a bit with the MP2. I notice Dante has put both the MP1 and MP2 guides up as a download. And I believe there are efforts afoot to recreate some of the old Depot pages where you could check out the different ADA products from over the years. Also a few of the old crew are coming back to join this new forum so it should continue to get better.
Cheers R
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Well, I seemed to have solved the wah issue temporarily...by stumbling upon another MP-2 in a tiny local pawn shop...for just $100! That said, I'm going to fix the other one in a couple months and I may look to mod that one to go along with the needed repairs on it. That way I can see what a modded MP-2 would sound like.
Sooo...
:banana-trip: :banana-upsidedown: :thumb-up:
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You doing well with the purchases, $100 is a steal lucky the pawn shop doesn't know what it really is :thumb-up: I need to get another pedal so I can assign it to the wah, I wanted 2 but the MXC pedal pack only had one in Australia when I bought it.
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I wish it were them not knowing what it was, because I got it half cost. This pawn shop is about 1/4 the size of a normal US pawn shop floor space so I figure that he was just trying to unleash it for quick cash. Then after firing it up and thorough testing and I found out the compressor is shot...not that I use compression very much. There is one component rattling around inside so I will investigate it. That being said, the wah works very well with this one so this MP-2 will be getting use in the near future.
I have been doing well with purchases, but damn if there hasn't one bug in everything that I have bought lately. :-\
At least it is more than usable, especially after i dial out the compressor out of all the presets and go to town on the rest.
Oh, and I took my other MP-2 with the B200S out for a jam a couple days ago and it comfirmed what you said: MP-2 and B200S are a great match. So thanks for the advice!
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No worries, bummer about the compressor, I don't use mine much either, I do use it for my clean patch though.
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I can finally see what you guys are saying about the MP-2, really is a nice preamp with the requisite time involved dialing it in. The original one that I bought definitely sounds a little different and not in the best way, probably needs new tubes and cleaning...and the wah and display fix.
Compressor be damned, this thing sounds great anyway.
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Yeah I'm a convert for many years now, the MP1 was/is great, I find the MP2 even better :thumb-up: and the cab sim outs are great for recording. I have 2 MP2s, same tubes but they both sound a little different.
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So it has been a long time since I last updated on this thread but the original wah-malfunction MP2 is undergoing it's long-delayed repairs and upgrades that I have intended to have completed. Long story short: upgrading op-amps and noise mod, fixing the longstanding wah sweep issue (MJMP I will inform you of what caused this once it's done). Afterwards I will give you guys an idea of what the mods do for the sound of the MP2 as I will compare it with my other one. I'm hoping for something truly sick! :whoohoo!:
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Cool :thumb-up: looking forward to hearing about the results. A good working MP2 is what floats my boat >:D
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Finally, the long awaited (from my self at least) results of the mods:
The Tone Doctor of Houston, TX did an op amp upgrade, replaced a work filter cap, and performed a noise mod on my wah-plagued MP-2. Unfortunately I will have to track down a new chip to get the wah in order. But as long as I have a wah pedal, it's only window dressing. Here are my impressions:
1. The tone really opened up. The overly muddy bass frequencies were fixed. Now I can really chug when I palm mute without thudding even at the highest gain settings. Treble breakup is a lot more natural, though definitely still in the Marshall camp. The tone is no longer compressed like my other MP2 is at similar EQ variances. Even my darker sounding guitars really shine as well as the telecaster bastards that I normally use these days
2. With the noise mods, the noise gate is no longer getting heavy use, except for rhythm playing at the most extreme gains. It's like I am dealin with a whole new beast that I no longer have to fight against at times.
3. Clean channels have a little bit more sparkle. As I record R&B as well as my usual metal diet, this is also a very welcome result.
Overall I got exactly what I was looking for when I sought out the mods. I would recommend it if you do wish to go the same route. All thanks to Tone Doctor on this one. :banana-rock:
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Good news indeed :thumb-up: Wouldn't mind a detailed break down of exactly what they changed etc :wave:
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Will have to see about that next time I come across him I have two more projects lined up.
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No worries, but I'd like to know the details so I can consider for my 3 MP2s, I'm trying to modernise them and future proof them as much as possible.
But very glad yours is performing so well, actually, at the moment, all of mine seem to be doing fine but I'm about to embark on some upgrades, go a bunch of parts now and been practicing my desoldering skills. Did he do the same noise mod as the kit MJMP put together (21 caps and new 1 % R913 )?? Also keen to know the opp amp details, well everything really >:D
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Hello.
My wah is not working also. I change the parameters of all kind of wah types but nothing works. Any news for this topic?
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Did you try to repalce the 2 opamps U205 and U207 (OPA2604AP)?
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I have bought my mp2 1-2 months ago and no idea where these things placed in the board. Today I looked at the schematics but I understand nothing. I am just a plug and play guy. I think I have to learn some technical stuff.
Will It be funny If I attach the picture of the board to get help from you ?
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see pdf,now you need to get OPA2604AP opamps nothing else,these are the only opamps i know that can have +-24V supply voltage.Now these are easy to replace since they are in a socket.Just make sure you insert them the right way.
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Many many thanks. I have searched these opamps in local stores but couldn't find yet. I will look 1-2 more place here, if I can not,I will order from abroad..
I think you've marked another circuit upwards what is that ?
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That R913 which can go up in value and causes the voltage regulator to fail.Resulting in a lot of noise and other problems.Maybe while you're at it replace that one with a 240k 1/2W metal film resistor.It will fail sooner or later.