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

ADA Preamps => MB-1 => Topic started by: Andrea86 on May 21, 2014, 04:19:10 AM

Title: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 21, 2014, 04:19:10 AM
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
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 21, 2014, 06:16:07 AM
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: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):
Regards Richard
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 21, 2014, 06:20:24 AM
You may want to check this out BTW (http://adadepot.com/index.php?topic=446.0;topicseen)
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: MarshallJMP on May 21, 2014, 08:38:33 AM
Maybe somthing is wrong with the +-15V?
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 21, 2014, 09:41:02 AM
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
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Peter H. Boer on May 21, 2014, 11:43:46 PM
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
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 22, 2014, 02:29:24 AM
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!!!
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 22, 2014, 07:15:06 AM
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:
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 22, 2014, 07:37:44 AM
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?
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 22, 2014, 08:06:26 AM
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???
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 22, 2014, 02:17:23 PM
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...
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: MarshallJMP on May 23, 2014, 02:03:37 AM
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.
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 23, 2014, 04:17:22 AM
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!!!
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 23, 2014, 08:51:03 AM
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...).
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 23, 2014, 10:43:46 AM
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.
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: MarshallJMP on May 24, 2014, 01:28:32 PM
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!!!

Let's hope it will fix the problem.
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 25, 2014, 04:55:23 AM
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.
Hi Andrea, S's and T's are terms I'd normally use from a vocal perspective rather than say e.g. 4khz- 6khz to describe what, particularly early compressors, did/do to the signal.  So you tended to loose definition/sharpness/clarity (S's and T's sounding flat/muddy) unless you spent big $'s on the unit.
From your posts, the way you use compression (very sparingly) sits well with my thinking. I'm not a big fan of compressors, they have their place/uses (like peak limiting so you don't blow speakers, noise reduction for recording to tape (DBX, Dolby A)) but (in my experience) they are often overdone/abused/misunderstood IMHO and often to make up for other inadequacies
Cheers Richard
 
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 25, 2014, 10:52:58 AM
i agree, nowadays many records sound very soulless because of all these abused compressions...
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: MarshallJMP on May 25, 2014, 02:06:52 PM
i agree, nowadays many records sound very soulless because of all these abused compressions...

+1 :thumb-up:
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 26, 2014, 05:34:56 AM
These days they seem fixated on creating the loudest CD possible (so squish it all up, up, up..., no dynamics/holes/spaces yuk).  But also in my early days engineering, I knew sound guys that would run 8:1 comp on a live mix (and set thershold so most/all of the mix was compressed), they'd sit back and drink their beer and read the paper.... sounded crap (and no S's and T's LOL).  Live these days it seems they idiots can't get the crossover point for the sub(s) right (a good invention (subs) but even more abused/misunderstood) which makes the bottom end of the bass guitar sound like mud (dooof dooof ....).
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 28, 2014, 11:36:46 AM
The SSM2120 is arrived. I put it into ADA but nothing changed. When i turn compression on it goes distorted. So i would like to prove to reset ADA but i don't know how to do. You know how reset MB1?
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 28, 2014, 02:24:23 PM
ok i read the instruction and i have done all the resets possibile... nothing changed. Really i don't know what to do, i'm totally lost. After buying the SSM2120 i hoped that my problem was solved but it's not. Maybe putting a EPROM 2.05 (instead of 1.19 that now i have) should solve my problem?
Sorry if i'm so a ball breaker :) but i'm really stressed about this problem.
Andrea
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 29, 2014, 03:44:45 AM
A friend of mine told me that MB1 can be resetted while it's off but he didn't remember how to do. Do you know something about this technique of resetting?
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 29, 2014, 06:11:02 AM
Bummer it didn't work, but hang in there, I'm sure MJMP will help get you sorted, I'm not across a MB1 reset procedure but Peter or MJMP should know if and how it can be done.
I doubt the EPROM update will fix it unfortunately, but it won't hurt anything.  And it does bring new featues like Continuous MIDI control (CC) I've attached the v2 manual (as your EPROM on the way is 2.05).
It seems it's not the SSM2120 (asuming the new one is good, I suspect it is and it's a different problem).  Ok so you turn compressor and distortion, turn off all ok.  Compressor IC seems fine (you put in a new one), my guess is that the compressor input is being overloaded, or it's overloading whatever (the circuit components) that come after it.

Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 29, 2014, 07:11:56 AM
If you haven't tried this, here's an idea:
Make sure the compressor gain is set to lowest (1).  Manual says only need to turn up gain for ratios 10:1 or more (and obviously threshold set such that signal is being compressed).  But regardless of ratio/threshold settings (lots of comp to little or no comp) the comp gain is still in the chain and can easily overload the next stage.  Moreover, this will be transistor distortion (not pleasant like tubes, takes lots of tricky circuitry (e.g. dist pedals) to make transistor distortion sound usable).
You use quite light compression, so you don't need to boost the gain (just make sure comp vol/level in = comp vol/level out, to test: comp switched out = same volume as comp switched in).

I didn't think of this before as the MP1/2 (which I'm familiar with) don't have comp gain control just threshold and ratio.
Cheers R
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 29, 2014, 07:56:08 AM
Ok. More or less i understand what you mean. But I have tried to let Gain at the minimum but still the same story... Anyway in a hour i'll be at home and i'll try in a better way ad you told me.
Thanks :)
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 29, 2014, 08:03:41 AM
If compressor on/in , gain at minimum (1) (and ratio and threshold so no compression) and still distortion, and new comp IC, then there is some other problem, and this is much more MJMP expertise, but hey worth a try  :wave:
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 29, 2014, 08:06:53 AM
Hope they will reply as soonest :)
Thanks i'll let you know about your solution
 
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 29, 2014, 08:16:12 AM
You can PM either of them (MJMP or Peter), I think Peters on holidays, you can also email MJMP, he's in Belgium contact email from here (Members MarshallJMP) or from his web site (http://www.marshalljmpmodshop.net/index.htm).
I hope it's just a gain issue but I posted the MB1 PCB layout in case you need it for your Tech friend (or yourself..)
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 29, 2014, 08:45:21 AM
i've tried as you told but if i am at 1,5:1 or 40:1 ratio, the noise is the same so i think it's more difficult that we think...
thanks a lot anyway, for all your support :)
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: MarshallJMP on May 29, 2014, 02:40:57 PM
I'll check it out in the weekend,i'll look for possible sollutions.Sorry it didn't work out with the SS2120.
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 29, 2014, 09:52:25 PM
Ok thanks a lot :)
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on May 30, 2014, 05:57:11 AM
i've tried as you told but if i am at 1,5:1 or 40:1 ratio, the noise is the same so i think it's more difficult that we think...
thanks a lot anyway, for all your support :)
No worries, happy to help and very interested in what MJMP can suggest.  But don't let it stop you doing the other upgrades (in the order I'd do them - Tubes (Mmm NOS RCAs', melt me... :thumb-up: ), EPROM, MDRT), they'll all help in their ways for everything else.  Worst case scenario (although I'm sure you'll get the compressor sorted out), is leave it out and use  (if you want compression) an out board compressor ?, you could run it it one of the MB1 loops, probably the first one, but I need to check Peters flow post....
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on May 30, 2014, 09:41:20 AM
I've bought a couple of EDISVAN TUBES (very similar to Mullard), great stuff!!!! Even better than RCA in my opinion... Anyway I'm waiting for an answer in these days about the ADA. I keep fingers crossed :)
Thanks
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: rnolan on June 02, 2014, 12:39:08 AM
Cool, glad you got the tubes sorted, even better you like them more than the RCAs', has your new EPROM arrived ?
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on June 02, 2014, 07:42:37 AM
Not yet. I'm still waiting for some news from JMP about the compression problem. Still fingers crossed eheheheheheh
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: MarshallJMP on June 03, 2014, 02:19:28 PM
Well it could be U14 (TC9164N),U2 or U29.Now i'm only guessing here,it's hard to diagnose without seeing the unit.
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on June 05, 2014, 01:01:12 PM
ok thank you so much. i will try to change these units as soon as possible and i'll let you know :)
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: MarshallJMP on June 05, 2014, 01:20:35 PM
BTW U14 is in a socket,the rest is soldered.
Title: Re: ADA MB1 Version 1.15 Troubleshooting
Post by: Andrea86 on June 20, 2014, 02:13:30 PM
i've putted the TC9164N but it's all the same... :(
I've changed the EPROM too (i've bought the 2.05 version) but when i start on the screen there's written this:
8.8.8.8. and all lights' on... don't you know why?