SSL 9K Mic Pre Thread 2009

[s2udio]

Map component voltages on a working channel at a given input ...then compare with the non working one....
also simple continuity checks point to point can often reveal the culprit quickly.....
With 3 working channels it should'nt be rocket science..
Check once ,twice,thrice...and be logical

 

[TheGuitarist]

I checked the ic voltages, the only one that was off was pin 5 on the output ic, which in the two times i checked was 120mv and 720, compared to the rest that were all a steady 670.

Also, when i increase gain, the transformer audibly gets louder, its not loud at all, but i can hear something.


Any other key points i should be checking voltage at?

 

[TheGuitarist]

i've got all the grounds of all the preamp boards strung together, the ground on the screwy board is screwing up other channels, it makes noise when the pot on the dodgy channel is turned on other channels on the preamp, but when i take that board out of the chain, all the noise goes away. So it makes me think there is a grounding problem?

I'm at a loss at the moment.

 

[mushy]

http://www.groupdiy.com/index.php?topic=17839.msg207611#msg207611

 

[TheGuitarist]

Cool info in there, but the rest of the boards are working fine with my grounding scheme... i'm starting to think i might just have a dud board.

Another note, the sound from channel 3 is bleeding into channel 4 when nothing is plugged into the input of 4 but in 3. Channel 4 works perfectly by itself.

 

[mushy]

Which all points to something being farkakte with your grounding scheme...  Time to rethink...  Rotate your cards... Does the problem follow the card if you swap it with channel 1?

 

[TheGuitarist]

I'll try that, but something worth mentioning, when it is connected to the grounding scheme, phisically moving the wire (while everything is still connected) increases and decreases the noise.... now that confuses the hell out of me.

 

[mushy]

Which wire?

 

[TheGuitarist]

i have the ground wires linked between each board, its the ground wire between the third and second preamp board.

 

[s2udio]

Then check all ground connections for continuity.........also the current draw on +/- and 0v power rails at each module

 

[audiophreak]

Hi All,
        I have just fired up a quad of 9k's, seems to be working, and on my own voice through a 58 sounds fine, no hum or buzz or anything 

  However I have one channel that is very " scratchy "  and the level is low, in checking I found 10vdc across the " A "  gain to pot, guess that's the " Scratchy ". In looking at the schematic it looks like the "A" gain is feed from the MAT-02.

  Not sure if the MAT-02 is bad or  if something leading to it is bad or wrong and not sure how/what to test  :-[

  any and all advice welcome
                                        Thanks

 

 

 

[s2udio]

Check the pots resistance, and as you have three working modules.........shouldnt be hard to find with the right procedure..
I Find good old continuity testing first,  irons out basic wiring mistakes and bad joints on new builds , no power required

 

[audiophreak]

Thanks 

  What I am getting is 15.8vdc on the two leads going to the "A" gain, when connected to the pot it drops to 10.4vdc and drops to 0.006 with pot adjustment.


  I have swapped Pots - no change - I replaced MAT-02 - no change .  :'(

checked the other three channels and they all have 0v on the "A" gain leads. I have no real " circuit " tracing skills ( need to improve on that )  ;D 

will  now remove that channel  and a working one and go pad to pad.

... any other thoughts ?  .... anyone ? 

 

 

[briomusic]

audiophreak, I had a similar problem and it turned out that I forgot to solder one of the necessary jumpers. have you doublechecked they're all there? cheers

 

[s2udio]

checked the other three channels and they all have 0v on the "A" gain leads. I have no real " circuit " tracing skills ( need to improve on that )   ;D 

will  now remove that channel  and a working one and go pad to pad.

Now you're on the right course.......and dont worry about voltages at the moment.....continuity is the key
and follow the schematic !

 

[audiophreak]

Thanks briomusic 
        I believe I have all of them in but will check tomorrow.  actually I think those were the first things done but I just had the chance to put it all together these past weeks.

  s2udio - sometimes I still look for the quick answer, but most times I just need a kick in the butt to recognize the opportunity to learn  ;D    Thanks !

 

[audiophreak]

Hi All,
   Want to give a little warning - Do Not  purchase MAT-02s from UTSOURCE International(S) Pte.Ltd.  
 I just spent way too much time, money, pulled too much of what little hair I have left in figuring out why one channel of four was not working correctly. I checked , re-checked replaced components, bought new PCBs from Gustav, could not find problem with this one channel.
  I had found three MAT-02s from a US source, purchased them, I think I paid $12.00 each , and the packages they came in looked like they had been on the shelf for years. Wanted to build a quad though, so I searched and found UTSource, they had a California office and were $8.00 each, I bought six,  -  WELL - I put two " Vintage " Mat-02s in channels 1&2, and two from UTSource in channels 3&4, channel three was the one giving me problems. Even after all I did, I swapped out the Mat-02 THREE times and still had same problem. In a last attempt I tripple checked all new components in a new PCB and got the same result !   - out of despiration I replace the Mat-02 with the last one I had, that happened to be a " Vintage one "  and it WORKS !!  

   So it seems only ONE out of the SIX I purchased from UTSource were good. I am calling them today to atleast let them know, but dont expect anything.
   
   Well, now I have four functioning SSL-9ks, they sound great, and have parts enough for two more - except the Mat-02s  


  EDIT :  I have found that Analog Devices now has a replacement for the mat-02 - called the MAT12AHZ    and have submitted a request for samples - will let you all know if I receive them

 

[bruno2000]

Hi All,
   Want to give a little warning - Do Not  purchase MAT-02s from UTSOURCE International(S) Pte.Ltd.  
 I just spent way too much time, money, pulled too much of what little hair I have left in figuring out why one channel of four was not working correctly. I checked , re-checked replaced components, bought new PCBs from Gustav, could not find problem with this one channel.
  I had found three MAT-02s from a US source, purchased them, I think I paid $12.00 each , and the packages they came in looked like they had been on the shelf for years. Wanted to build a quad though, so I searched and found UTSource, they had a California office and were $8.00 each, I bought six,  -  WELL - I put two " Vintage " Mat-02s in channels 1&2, and two from UTSource in channels 3&4, channel three was the one giving me problems. Even after all I did, I swapped out the Mat-02 THREE times and still had same problem. In a last attempt I tripple checked all new components in a new PCB and got the same result !   - out of despiration I replace the Mat-02 with the last one I had, that happened to be a " Vintage one "  and it WORKS !!  

   So it seems only ONE out of the SIX I purchased from UTSource were good. I am calling them today to atleast let them know, but dont expect anything.
   
   Well, now I have four functioning SSL-9ks, they sound great, and have parts enough for two more - except the Mat-02s  


  EDIT :  I have found that Analog Devices now has a replacement for the mat-02 - called the MAT12AHZ    and have submitted a request for samples - will let you all know if I receive them

I bought some "counterfeit" MAT02s from UTSource a while back, and measured and labeled hfe on every one of them.  Although the good ones were all above 600, and matched within 2 units, I did have a failure rate of about 4%, but I only paid $1.50 each for them, so I was happy.
Best,
Bruno2000

 

[JAY X]

Hi All,

I started building this preamp a year ago, but let it apart for a while, and now i re-take it to give it a last push.
I used National LM394H for mat-02, and TL2082 instead of TL052. NE5534AP for the rest. all IC's/sections run at 18volts, so there is no need for a second PSU.

I have three questions regarding this preamp/balancing board.

1. I am using ssm2142 as output balancers, that i built with normal 100uf electrolytics, but after AD design notes, 100 UF NP (non polarised) capacitors must be used at the output stage.  ¿ maybe this is why i got no sound? and all caps turn hot rapidly when i turn it on.

2. When i soldered all the parts i used a tin solder that sprinkled a lot of flux. ¿may this flux even dry create a bad contact?

3. Non polarised electrolitic capacitors have an anode and cathode as regular electrolytics. ¿should NP electrolitics be placed as normal electrolicts respecting polarities?

thank you for your help.

JAY X

 

[audiophreak]

Hi All,

  Wanted to post a link to some pix of my quad SSL9k.    http://picasaweb.google.com/audiophreeek/SSK9k?feat=directlink

  Thanks to Kieth, Neeno, and everyone here, I have a lot to learn, but have learned so much, Thanks !

  Dans front panels, pots from AML, mnats PSU, PCBs from Gustav.

  ... as you can see, the phase, 48v, and Pad are not hooked up and dummy switches are in place, I have a JLM Go between kit on its way from the BM, if it goes well, will get three more.

  I got the MAT12AHZ - right from Analog Devices.

  They sound GREAT !