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Author Topic: ADA MB1 Version 1.15 Troubleshooting  (Read 11873 times)

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Andrea86

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ADA MB1 Version 1.15 Troubleshooting
« on: Time Format »

Hi, i'm Andrea from Italy and i'm a new member.
I'm writing because i have some problems with my ADA MB1 version 1.15.
Problem N°1: Compression doesn't works. I have to set it OFF always because when i use it (also at the minimum)
the sound gets distorted and it's a complete disaster, total mayhem...
Problem N°2: Master control at both Tube and Solid State part doesn't sound good when i put it from 4.6 and over. i have to stay within 4.4 and obviously doesn't sound so punchy as it should works.
I'm completely without any idea of what kind of problems my preamp has.
Pls help me if you can!!!
Thanks a lot in advance.
Andrea
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rnolan

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #1 on: Time Format »

Hi Andrea, welcome to the depot BTW.  There's a couple of MB1 users here with lots of experience and they are sure to help out here as/where they can (go Bass dudes :thumb-up: ). But I can help a little I think.

A couple of questions to help trouble shoot:
  • How old are the tubes (they should be changed every year or 2 years, but depends on how often/long you turn it on), also they go off/degrade very slowly so you don't notice (until you put some new tubes in  ;) ), I suspect new tubes are a good idea regardless (there's quite a bit of discussion here re tubes, you'll need 2 x high gain low noise 12AX7 tubes (easy to change yourself BTW) I'd recommend JJ's (e.g. http://www.dougstubes.com/preamp-tubes/12ax7-ecc83-7025/jj-ecc83.html) or my fav, Mullard Short plates(http://www.dougstubes.com/preamp-tubes/12ax7-ecc83-7025/mullard-cv4004-12ax7.html)), Peter/BDS what do you recommend ?
  • what settings are you using when the compressor overloads (total mayhem (all settings in the distorting patch pls)) (this maybe gain issues or maybe a component problem ?) or a known problem ?
  • what bass are you using ? is it active? if so when was the last battery change (dieing batteries....?) ?
  • what power amp and speaker box, how's it patched ? or are you going direct into a desk/pa ?
  • do you plug through anything else before the MB1 (e.g. tuner, effect thingy) ?, do you use other effect devices in the chain ?
  • Are all your leads good ? (guitar/patch/speaker)
Also MJMP (who's our all things ADA tech guru  :bow: ) will be able to help, and not doubt have some more targeted questions...
Regardless of the current problem (which we can hopefully help sort you out soon), there are a couple of mods really worth doing (when/if you can afford $'s wise):
  • Tubes (2 x new 12AX7s)
  • The MDRT replacement transformer (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm), to me this is a no brain-er.
  • EPROM upgrade (easy to do yourself)  to v2.05 same page (on MJMP s site) as above.
  • There are also some noise mods worth considering (reduce noise in the MB1), Peter and MJMP are more across those
Regards Richard
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Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

rnolan

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #2 on: Time Format »

You may want to check this out BTW (http://adadepot.com/index.php?topic=446.0;topicseen)
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MarshallJMP

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #3 on: Time Format »

Maybe somthing is wrong with the +-15V?
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Andrea86

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #4 on: Time Format »

Hello to you all  :)
First of all thank you for your answers and your time! i really appreciate!!!
About the question you made:
- i changed the tubes but nothing happened...
- i used the same settings when the compressor worked, it broke up in a second while i was playing so in my opinion there's nothing wrong with the settings. Obviously i changed my settings after the compressor stopped working.
- i use a Fender Precision Bass directly plugged into the ADA MB1 and other stuff, here it is:
  bass > ada mb1 > trace elliot XV valve (1 tube) > DBX compressor (send return to the Trace elliot XV) > Trace Elliot RA 300 > Trace Elliott Speaker
Without ADA MB1 all works perfectly so it's only a problem about ADA...
So at this point probably it's a EPROM or Transformer problem don't you think?

Best regards Andrea
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Peter H. Boer

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #5 on: Time Format »

Problem N°1: Compression doesn't works. I have to set it OFF always because when i use it (also at the minimum)
the sound gets distorted and it's a complete disaster, total mayhem...
This sounds like something is indeed wrong with one of the components in the compressor section.
(Had something similar in my TLA VP5051 compressor, and a cap was busted there)
What and where, however is to technical for me, check (or have checked) this against the schematics.

Problem N°2: Master control at both Tube and Solid State part doesn't sound good when i put it from 4.6 and over. i have to stay within 4.4 and obviously doesn't sound so punchy as it should works.
The output of the MB-1 is pretty hot (it is made to directly drive a power amp). Are you maybe overloading the input of your Trace Elliot?
Why are you using the Trace pre-amp anyway?
I would go: Bass > ADA MB1 > Trace Elliot power amp. (use the DBX in the effects loop of the MB1)

Peter  O0
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Andrea86

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #6 on: Time Format »

I had the Trace Elliott before ADA so i have tried to put them together and the result was super!!! I've tried also different solution but for my taste this was the best by far!!! I have to check my ADA in a better way thanks to your suggestions :)
Anyway any other idea is welcome  thanks men!!!
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rnolan

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #7 on: Time Format »

Hey Andrea, thanks for the answers, it seems to me there's definitely an issue in the MB1 (particularly given it all works well without it ;-) and they are getting older unfortunately) (my thoughts are leaning with/between Peters 1st response, maybe a problem in the compressor circuit, quite possible (IMHO it's not the eprom but it's a very worth while upgrade anyway)), but MJMP may be more on the money here ?, and I tend to agree (he knows this stuff much better than me BTW), the symptoms you posted seem more than just gain structure issues (I just wanted to rule things out).  But Peter does make a salient point (particularly re gain (when it's all working fine again)), preamp (MB1) into preamp (Trace), mmmm not good gain structure, anyway, if it sounds good... that's patching ideas/issues, more important: why is your MB1 crapping out.
How are you with a multimeter BTW ??
(thanks men!!!)  Happy to help  :thumb-up: :wave:
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Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

Andrea86

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #8 on: Time Format »

Thanks again for your thoughts. It's normal having different points of view about amping and so on but the question that torments my mind is this: why the compression doesn't work in any kind of situation? This could be a Ratio or Gain too high?
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rnolan

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #9 on: Time Format »

Hey Andrea
Compression is all about shrinking dynamic range (containing) (relatively, not necessarily overall, i.e. turn up the result loud), i.e. make loud/big changes similar to low/small changes), down side to consider is that compressors tend to remove top end (not good), the really expensive ones do this better but add zeros..... Ideally you wouldn't use a compressor at all, how good are your finger dynamics ? As a sound guy (one of my other lives), I want the bass and kick to sit together, so I may compress them both slightly to help (anything more than 2:1 and you've lost me, why!!!), with bass, can you not play consistently???
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Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

Andrea86

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #10 on: Time Format »

i like bass dynamics and i don't like too much compression, in fact i used 1.5/2:1 and small ratio but it helped me a little bit.
However tonight at the rehersal i've solved (finally i hope) the problem with the Master Volume but Compression still doesn't work and probably it's
the compression circuit and absolutely i don't know where it is or what kind of part i should repair...
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MarshallJMP

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #11 on: Time Format »

Maybe there is something wrong with the compressor ic.It's called U1 on the schematic and it's a SSM2120.You could try to replace it with a new one.If i remember correctly it's in a ic socket so it's easy to replace.This ic has 22 pins so it should be easy to locate since it's larger then most ic's.The SSM2120 can be found on ebay.
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Andrea86

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #12 on: Time Format »

SSM2120 just bought!
THANKS A LOT!!!!!! :)
i will inform you as soon as possible if it works or not! You're great man really big thanks!!!
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rnolan

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #13 on: Time Format »

Hey Andrea, Glad you solved the master vol issue, hope the new IC fixes your compressor problem (I suspect it will), MJMP is an absolute gem  :bow: .
A little I.5/2:1 compression sounds good on bass IMHO but obviously where you set the threshold makes a big difference.  Also you can compensate a little for the loss of S's and T's by boosting the presence (~6khz) or the top end generally to get back the sparkle (depending how old the strings are...).
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Andrea86

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Re: ADA MB1 Version 1.15 Troubleshooting
« Reply #14 on: Time Format »

Sorry Rnolan but what do you mean when you say "S's and T's"?
However i set the Threshold near 0, i don't like too much compression.
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