SSL 9K Mic Pre

[briomusic]

I had this same problem on two of the 7 SSL9k's I built. On one of them I had forgotten a jumper, the other one I never managed to fix, just ended up harvesting the semiconductors and bigger wimas and started fresh on a new pcb. All the voltages were off and changing with the gain pot, that's as far as I got troubleshooting. Good luck!

 

[dmp]

Well, this morning I reversed the wiring on the gain pot and that didn't fix the problem - just reversed the orientation of the gain as you turn the pot.
Both of the units I built are doing the same thing.
Other people have had this problem (I read through the threads) and it seemed like it was incorrect dc / servo voltages, but I didn't find a solution. I'm using NE5534P & TL052ACP.
So as I start trying to trace the signal through the circuit, I think this is basically a balanced amp all the way to the last 5534 stage, meaning that the gain stages are applied to both the (+) and the (-) separately. The gain of both stages connects the negative feedback loops together, of the (+) and (-) to cancel?
Important test points would be at the output (pin6) of the 5534 chips, balanced - meaning that the reference is not audio ground but +/- between the upper and lower 5534 outputs?

 

[briomusic]

hi dmp, are you talking about tone-probing/scoping? you can still reference everything to Ground, you will just get phased reversed signals on the two "sides" of the pre-amp. When I tried this on my broken channel, I couldn't even get a signal anywhere at the first op-amp (with the gain pot turned up that is) so I assumed the problem was somewhere around the matched transistors. However, I am not sure if I am the best person to talk to, as I never really found a solution. Hope you have better luck!

 

[dmp]

I just measured the DC voltages and there is definitely a biasing problem. Without any input signal, the output of the top 5534 is down to -13v. It cannot get pin 2 (11.8v) down to the bias value on pin 3 (11.2v).
The biasing is setup with +16v through the voltage divider of R113 & R112, which puts the 5534 inputs at ~11.2v, which looks like it measures correctly. The emitters of the MAT12 should be a diode drop below ground, the top one is too high (-.13), which is the only problem I see, implying that that transistor is shut-off. I don't understand why this circuit would be biased this way or what is wrong with my build. Can anybody help?
It seems the resistor values are right and the opamps are functioning. I am running this on  +16/-16 by the way.

 

[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

  Dont know if this could be your situation, I am very much a Newb, didnt have to equipment of skills to test the MAT02's  ,  have replaced all with the new MAT12's and all is fine now, and I think they sound great !

Hope this may help, let us know what you find.

 

[dmp]

I got MAT12s directly from Analog Devices as samples.

 

[dmp]

Found the problem - was with the little jumper that connects to the 2nd pin on the upper opamp. Oops. Both are working now anyway.
Thanks for the help brio & audiofreak!

 

[audiophreak]

Happy to hear that,  enjoy ! 

 

[dmp]

Here are the DC voltages for the working preamp for future reference.
Note that matching the resistor pairs R105 & R69, and R109 & R73 is important to have the input section balanced and not have scratchiness when you turn the gain pot. I had the 1k resistors a few ohms apart and I could hear it on the gain pot. Fixed that and it is now very quiet.

 

[Morelius21]

Hello people,

Now I make two channels ssl 9k and I have a question.I want to put in channels phantom, pad and phase. I thought of using the kit JLM Go Between. Someone has tried it? Work?

Thanks

 

[briomusic]

yes the jlm go between is perfect for this. I tried wiring those three swiches off-board - a nightmare don't do it! I actually now retrofitted all my ssl9ks with go betweens.

 

[pedrocruz]

Now I make two channels ssl 9k and I have a question.I want to put in channels phantom, pad and phase. I thought of using the kit JLM Go Between. Someone has tried it? Work?

Hello Morelius21
I believe almost everyone here uses the Go Between whenever the preamp pcb they are cloning dont support PAD,PHASE,48V.
Im building 8ch SSL 9k and i got 8 go betweens to solve that issue and ive been told that they are great, also you can get the DI from JLM which is an easy connection to the go between if you would like to have DI input on the channel...
Hope this helps...
Cheers!

 

[Morelius21]

Thank you

Gracias 

 

[Morelius21]

Hi,

Someone could tell me which inductor he has used in the preamp?  I have doubts Thanks

 

[mitsos]

The little resistor-looking ones. Something like this from Mouser should work:
434-22-150

 

[dirtyhanfri]

Hi

I´m new in this forum, i have spent some time reading an re-reading a lot of threads and I´m going to make my SSL 9k mic pre.

I´m making a BOM from Mouser, but I´m not sure about the choosen components (I don´t know too much about this)

The caps are polyester film (Wima) and some ceramic disc (I looked some built units from this forum and the neeno pdf about it)
The Resistors are Carbon (and some metal) film resistors 5% tolerance.

Well, this is the BOM

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=182ecd4ef2

Could somebody take a look and tell me if it´s ok, or if it´s something wrong with it and help me?

I have some troubles with the rectifier bridge and the transformer, well, i have no idea about what to get. (I´m gonna build a 1u rack with 2 ch.)

Also, the Mat-02 transistor, could somebody share a link to buy it or some replacement?

I will get the Gain pot from audiomantenance and the Go Between kit for Pad, +48 and Phase Reverse.

I Think it would be interesting to get a 2011 BOM with mouser part numbers and another links to have all the info about this pre in one pdf. (I will probably make it while I build my unit)

 

[Hank Dussen]

MAT02 here: http://www.groupdiy.com/index.php?topic=41245.0

 

[dirtyhanfri]

Thanks

Anyone could tell me something about the BOM?

I´d like to say thanks to all guys sharing a lot of useful info in this forum.

 

[dirtyhanfri]

Nobody?

 

[dirtyhanfri]

Really nobody could help me with this BOM for the SSL 9k

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=182ecd4ef2


Thanks Guys.