SSL 9K & 4K (E Series) 500 / 51X NEW BOARDS Mic Pre Thread 2011

[culteousness1]

Burning R1 and R2 indicate shorts on both supply rails. So your meter board is probablyTM fine as it runs only off the positive rail.

Would suggest to remove all ICs and re-insert them one by one. Check for continuity on the supply tabs each time.
Also do a visual inspection of all IC sockets and their solder points. Look for IC orientation as well.

Carsten

 

[Vac11]

Thanks both.  I'll try check the IC´s. Meter is ok. Two hours it worked perfectly...

I have a rack from vandaalelectronic ( user served) - this is a 51x rack (both posibilities - 500 and 51x).  Can do it the last 2 pins in the socket? I did not remove it...

 

[culteousness1]

The two extra 51x pins shouldn't be a problem as they are not connected on the board.
They even help you to align the board properly in the edge connector. No worries  8)

 

[Vac11]

Hello,

the problem seems to be solved ... I pulled out all IC´s from their slots. After reinstalling everything worked fine. Thank you for your help !!! My first DIY project seems to be alive ...

Vac11

 

[dipfrik]

That was easy
What a straightforward build! Thanks Bruno & Gustav!
Need to finish the meter and of course a nice panel.

One short question: Is it too late for my ears, but i'am noticing a gain jump plus a really nice brilliance "top end"-ish push if i engage the HPF without dialing it in. Or is this, because i didn't calibrate it right now?

Thanks, Sven
PS: special thanks to culteousness1! <- you know why

 

[Whoops]

Anyone has one or two spare 4K boards that would like to sell me?

Gustav is out of boards and probably will not do any run soon.

thanks

 

[Vac11]

One short question: Is it too late for my ears, but i'am noticing a gain jump plus a really nice brilliance "top end"-ish push if i engage the HPF without dialing it in. Or is this, because i didn't calibrate it right now?

I have the same experience. So far I didn´t calibrate the preamp...

 

[culteousness1]

No worries, guys. This will be fixed once the pre is calibrated.
You have to set the knee and the overall gain of the HPF.

Carsten

 

[Vac11]

This "boost" sounds fantastic. I like it very much. I was pleasantly surprised when I first heard my singing through the preamp. Perhaps I have calibrated...

 

[dipfrik]

No worries, guys. This will be fixed once the pre is calibrated.

Worries? I think about never calibrate this unit ever!

Cheers, Sven

 

[Kevin]

Hi Guys
i had problems with the LED Meter. Not the mentioned problems shown already up here. First the LED Meter worked for months fine.  Then suddenly one part of the led meter segment doesn't worked anymore. First i thought about changing the LM3915. That was not the fault the LM3915 worked fine. I found the problem that between solder joint 2 and 4 of the LM3915 was no good GND connection. Funny thing about this was that this happened to two channels on different Segements of the LED Meter. I am Sure that i had no cold solder joint there. But i used IC Sockets on that ones. To fix this problem i soldered some lead between 2 and 4 and this fixed the problem

 

[tzman]

I just built two of these and one has a problem that I can't track down...
It works great, sounds great and all voltages are correct, but as soon as I put the gain beyond "4 o'clock" the preamp starts oscillation like crazy. So crazy it fried a THAT chip...
Weird thing is, the same thing happens when I reverse polarity on the preamp, only then it stats as soon as the gain is set beyond "1 o'clock".

This happens both with microphones connected to the preamp and without.
I've swapped all IC's, the MAT02, gain potentiometer, calibrated the HPF, all without luck...

Does anyone have the same problem/know where to start troubleshooting?

 

[culteousness1]

Check all resistors related to the op amps. Could be a cold solder joint at a feedback net causing stability issues.
As you have a working unit, compare them in every detail to find the error.

Best of luck,
Carsten

 

[tzman]

Thanks!

I think it's indeed the best approach to just compare them... Any tips what to look for first? Starting with tracing the AC signal, looking for DC offsets, etc?

 

[Graph]

Hi, one question about 9k5 preamp.

I got the PCB, and sourced the components, what i missed is the bridge and i cant find a bridge so small to fir there(all i have legs are too big). Is there a problem with using 4 diodes to make the bridge? Some legs will be soldered with each other. If there is no problem about it, which diode should i use? 1n4004? 4148 is too small for it?

Thanks!!

 

[Whoops]

Hi, one question about 9k5 preamp.

I got the PCB, and sourced the components, what i missed is the bridge and i cant find a bridge so small to fir there(all i have legs are too big). Is there a problem with using 4 diodes to make the bridge? Some legs will be soldered with each other. If there is no problem about it, which diode should i use? 1n4004? 4148 is too small for it?

Thanks!!

BR legs can be a bit fat sometimes for the holes in the PCB's,
what I and most people normally do is to drills the holes a little bit bigger so the BR legs will fit there.

you can have a small inespensive electric drill like this:

http://www.google.com/imgres?imgurl=http://www.lulusoso.com/upload/20120302/Small_hand_drill.jpg&imgrefurl=http://www.lulusoso.com/products/Small-Hand-Drill.html&h=600&w=800&tbnid=VCI0e6JCcOaz_M:&zoom=1&docid=vWpU7aMvSqYBDM&ei=6vIIVfP3FIPZU5uYgJAF&tbm=isch&ved=0CFcQMygxMDE

Or do it manually also:

http://www.wallaceracing.com/Idle_tube_drill_index_and_pin_vise2.jpg

 

[Graph]

Great! I can drill it manual, but there wont be any problem soldering it?(if the hole will still make contact), 5mm drill will do the job just fine?

Thanks!

 

[Whoops]

Great! I can drill it manual, but there wont be any problem soldering it?(if the hole will still make contact), 5mm drill will do the job just fine?

Thanks!

You dont want to destroy the solder pad, just open the hole enough so that the BR leg fits without completely sacrificing the solder pad.

 

[Graph]

Yeah, sorry 0.5mm i will try how much it needs

Thanks!!!!!! I want to finish them quickly but i dont have my lunchbox yet only rackit module for testing.

 

[kustohm]

Hi Everybody!
I'm a french DIY-beginners who try my best to do the best... (and try my best to speak a readable English :-[sorry)
I've already made 4 pres by myself (2 neve style & 2 API style), they work like a charm!
So, I would like to realize THIS 9K pre...BUT even if I read and reread all the topics and discuss, I do not stay completely safe about the FINAL-GOOD-BOM!!! Maybe I'm wrong but my starting point is the Piotr's Excel BOM which seems to be the most correct.
For example the IC1 is an obscur part of this project...(?) There some equivalent MAT?
Can somebody could help me?
Many Thanx for all Diy'ers and to Bruno2000!!!