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

[bruno2000]

<shameless plug>
Gustav now has the 4K boards in stock, and ready to ship.
Best,
Bruno2000
</shameless plug>

 

[NoBass]

Hi all,

Thanks for the replies, I didn't feel all alone with my problem

The rectifiers were the only component I had a doubt with the pinout, and I think you guys were right.

So I changed the pins, put some insulation to prevent any short, and plugged one in. On the first one it partially solved the problem, whit the card being still noisy, and when in the last quarter of the gain, it begins to send out a VERY hot signal (oscillation maybe ?). The switches are still popping a lot.

On the second card, I did the exact same thing, insulation on the pins of the rectifier, but when I plugged it in, R2 caught fire immediately !

So I guess my problem is a little more complicated...

 

[bruce0]

Glad rectifier helped.

And... Well I can't speak to the fire...

But Maybe you should get a loupe and look at each and every solder joint and look for bridges or unsoldered parts.
If it was me I would check all the stupid stuff, IC's oriented correctly, diodes oriented correctly. all parts installed.  All junctions soldered. No solder bridges.


With respect to the oscillation

i did have very bad oscillation on one unit when I first put it together, especially with the HPF turned on, (one just worked fine, the other whooped when I turned on the HPF).  I fixed mine by doing the HPF calibration procedure (to fix it all you need actually is just the first step, which is to turn one of the pots all the way one way ( left I think, maybe right?)... look at bruno's procedure.  After that the oscillation was gone.). 

Correction: Of course to properly calibrate the HPF (so that level changes don't occur when it is in vs out, and so that the response curve has no ski jump when you engage the HPF) you need to finish the procedure (I did not mean to imply otherwise).  But to get the oscillation to stop, all I needed to do was to turn down that calibration pot. 

Switches popping... I have no idea.  which switches pop?  That might give us a clue.  Switch pops made sense with the Phase switch and DC on on output...  but I have no noisy pops.

 

[bruno2000]

Glad rectifier helped.

And... Well I can't speak to the fire...

But Maybe you should get a loupe and look at each and every solder joint and look for bridges or unsoldered parts.
If it was me I would check all the stupid stuff, IC's oriented correctly, diodes oriented correctly. all parts installed.  All junctions soldered. No solder bridges.


With respect to the oscillation

i did have very bad oscillation on one unit when I first put it together, especially with the HPF turned on, (one just worked fine, the other whooped when I turned on the HPF).  I fixed mine by doing the HPF calibration procedure (to fix it all you need actually is just the first step, which is to turn one of the pots all the way one way ( left I think, maybe right?)... look at bruno's procedure.  After that the oscillation was gone.). 

Switches popping... I have no idea.  which switches pop?  That might give us a clue.  Switch pops made sense with the Phase switch and DC on on output...  but I have no noisy pops.

To correctly set up the HPF "knee", you can use the wav file (link on first post).  It's a sweep from 1KHz down to 10Hz.
There might be a small "pop" when engaging the pad, but certainly not the HPF or polarity switch.
The fact that R2 burned up says to me that there is a direct short somewhere. Check for solder bridges across the small bypass caps.  Try running it without the meter board.  If that works, check the known error on the meter board.  You may not have completely cut the trace.
Good luck!
Best,
Bruno2000

 

[audiorock]

Hi.

I am testing a channel SSL9K.

As soon as I turned on the power supply (+15 V 0-15V), It burns the resistor R1. (r1= 10F fused)!?!?
What is the meaning of 10 fused?

This resistor is 1/3 watt (The MOUSER code indicates to me that!) (ccf5010r0fkr36) or (71-CCF50-10)

The resistor should have been to 1/4watt or 1/2watt?

What is the problem you think?

Thanks.

 

[bruce0]

10R Fused

Is a 10 ohm resistor.

In the US they are them Fusible resisters, or fireproof resistors.  I don't know where they call them Fused.

In a nutshell.
What it means is you can design in a low wattage resistor,  INSTEAD of designing a fuse in the circuit, and hopefully because it is fireproof it will burn out to an open circuit and protect the circuit if the current gets too high... without catching on fire or catching something else on fire .  In order to determine just how fireproof or whatever they are you must read the specs...  (I. E. I am sure it is possible to start a fire with a fireproof resistor under various conditions).

In these 9k boards.. The "10R Fused" resistors act as a fuse for the circuit.  If yours is burning out perhaps you have some solder bridge across adjacent pads, or some other short. 

b

 

[audiorock]

10R Fused

Is a 10 ohm resistor.

In the US they are them Fusible resisters, or fireproof resistors.  I don't know where they call them Fused.

In a nutshell.
What it means is you can design in a low wattage resistor,  INSTEAD of designing a fuse in the circuit, and hopefully because it is fireproof it will burn out to an open circuit and protect the circuit if the current gets too high... without catching on fire or catching something else on fire .  In order to determine just how fireproof or whatever they are you must read the specs...  (I. E. I am sure it is possible to start a fire with a fireproof resistor under various conditions).

In these 9k boards.. The "10R Fused" resistors act as a fuse for the circuit.  If yours is burning out perhaps you have some solder bridge across adjacent pads, or some other short. 

b

I solved the problem! It was a track on the vu-meter, which was shorted to ground (+0 v)

This issue is described in the first topic! I was not paying attention!

Instead, there is another problem.

The resistor R1 and r2 are the problem! Infact, when I power the card, this resistors heat up too much, to the point of emitting bad smell (burning smell)!

What does this mean?
This happens when I insert all the operational amplifiers (NE5534, TL072, That...), instead when I not insert the OP amp, this resistor are cool, as normal.
Is there an abnormal absorption of current?

There is another problem in the circuit? Where is the problem?
I'm confused!

 

[Piotr]

Reversed Opamp maybe ??? Solder bridge ???
My 9Ks worked like a charm on first power up without me being very trained on electronics, so the project is certainly solid !!!

Good luck !
Piotr.

 

[culteousness1]

Gentlemen,

may I introduce you to my beautiful twins :

Both were working properly from first power up.

Thanks to Bruno2000 for a really nice project, to Gustav for those beautiful boards
and to Frank (NRG Recording) for the front panels!

I am already considering another pair...

Cheers,
Carsten

 

[sunnen1]

sweet!
the look great!

 

[Piotr]

Black does surely look serious ! Congratulations !!!

 

[bruno2000]

Very nice build.  Front panels look great.  Hope you enjoy them.
Best,
Bruno2000

 

[sunnen1]

sweet!
very nice indeed: )~

 

[culteousness1]

Thank you for your kind words!

I just ordered some 4K boards from Gustav's leftovers. So there will be another pair of these beauties soon.
Anyone interested feel free to PM for my front panel file.

Best,
Carsten

 

[bruno2000]

How do you like the sound?
Best,
Bruno2000

 

[culteousness1]

How do you like the sound?

I recently did a little comparison at a friend's studio. We took the first commercial preamp at hand, the 9K and a stereo mic to record acoustic guitar. So the chain was as follows: Neumann SM69 -> 9K / SPL Goldmike -> Yamaha DM2000 -> RME Interface -> Samplitude.

I know it's hard to compare these preamps as their design is a complete different. But we both liked the sound of the 9K very much. It was more musically and not as sharp and harsh as the SPL. I even had the impression that the 9K added some super light compression to peaks. Overall it did a very good job on acoustic guitar and in my opinion it could be even more useful on drums/percussion.

Maybe I will find time to upload the recordings in the near future.


On popular demand my frontpanel files can now be found here:
FPD - File
CDRX5 - File

Cheers,
Carsten

PS: Please excuse any bad typing or spelling, I just came back from Berlin and spent 14 of the last 24 hours in cars/trucks.

 

[audiorock]

Hi,
what are the alternative models of Cinemag CM-75101APC for SSL4k series?  (jensen, lundahl, OEP, etc)??

Thank you.
Fra.

 

[culteousness1]

Hi,
what are the alternative models of Cinemag CM-75101APC for SSL4k series?  (jensen, lundahl, OEP, etc)??

Feel free to read the entire thread. In reply #100 there is a list of all supported transformers.

Best,
Carsten

 

[bruno2000]

Here's a link to the 4K 500 / 51X schematic.


http://www.dopplerstudios.com/pictures/SSL4K51X16Sch.pdf

Enjoy!
Best,
Bruno2000

 

[Kevin]

Attention!
i wanted to use the Haufe ST8456 for the 4k, but the transformer footprints of the pcb will not work!
because the pins 5 ,6 and 8 are flipped.. maybe everbody else could buy the adapter pcb for the lundahl 1538, or what i will do, i will drill a hole more between 6 and 8.. maybe betwenn 0.8mm to 1,5mm hole and then a little cable to connection 6... not the best way but i ordered the transformers after i had the pcbs of the 4ks...