Sonosax SX-A Mixing console (VCA)

[etiefenthaler]

Dear Diy Aficionados

I recently bought a Sonosax SX-A mixingconsole (VCA Version).

Unfortunately I only got mixer but no Powersupply, manual or any other documentation.

On buying, I expected that I could find the Voltages indicated on the pcbs or somewhere inside the mixer. But sadly there is no such information.

The mixing desk is equipped with the following Modules:

4x SX-A06
8x SX-A01
1x SX-A02b


I would be very grateful if somebody could find some information about voltage assignment on Powersupplybus.

Thanks a lot

Erich Tiefenthaler

some Pictures:

https://www.dropbox.com/sh/jp2234vyohyr09j/AABcADgpjs-tdy3_ZgFoOd05a?dl=0


On Picture 39 you can see powerrail to modules.

My guess is: yellow = ground
red + 16V  (LM 341 M15)
blue - 16 V (LM 320 -15)
White goes to led`s : ???
Black maybe Phantom

 

[audiomixer]

I love the idea of reverse engineering all that, but in this case why not just ask the manufacturer? I am pretty sure they will be glad to help..... at least if you didn't nick it somewhere.... 

- Michael

 

[joaquins]

The decoupling capacitors close to opamps will tell you what voltage you shouldn't exceed, the pinout of the ICs will point you where each rail goes. For the voltage start from a much lower voltage than the rated on the electrolytic caps, they may be too high just because they have them laying around. Also if you have some voltage regulators that my give you a hint.

Once you've figured out where each rail goes a good way to start would be a dual tracking supply and start from 10V and start to raise it, looking for the current and stopping if it goes to high. If you could ask or find somewhere the rails voltages you need figuring out where them go should be pretty straight forward.

JS

 

[etiefenthaler]

Thanks for answers

@michael: first I did was contacting manufacturer in Le- Mont sur Lausanne..
They told me being very buisy at the moment - they  have to search in their archives.  This will take some time.  And it could be possible  that they will not find the neccessary  documents.
I also reported source of the console.  (Museum closing)
So why I do not just wait for response?  I am eager and I also would like to understand the consoles innards

@ joaquins:
Red  feeds Voltage Regulator 341-15, Blue Voltage Regulator 320-15.
341-15 input Voltage can be from 17 to 23v, 320-15 input Voltage can be from -17 to -35V
White feeds Dilrid-B 10L42 5V Relais directly and LEDs.    5V?
Black goes to 47 ohm then to pantom switch. 48V?

Erich

 

[joaquins]

one side 17 to 23 and the other 17 to 35? are you sure about that?

That seems to be your answers, I guess the phantom resistors are 6k8 as standard, if lower values are used maybe lower voltage is required, if the values are those then 48V it is.

If you have 5V relays directly into the rail then 5V it is.

For the ±15V regulators you want to have a little bit more than what they require so they can regulate, you have to be sure your ripple never makes the voltage from your PS under 17V at full load, in the worst case. So you probably need 18V or more, depending on the current consumption and the capacitance on your supply, that would require some experimentation but you already have a number to start.

JS

 

[etiefenthaler]

Hi joaquins

thanks for taking your time...

I uploaded LM 320-15 Datasheet and LM341-15 Datasheet on Dropbox. I found values for Vi on these datasheets.

Phantom values are: Supply Input - 47 Ohm - PhantomSwitch/ Mic Pin 3 to 4.07k and Mic Pin2 to  4.07k - PhantomSwitch

pdf Picure with Values is on dropbox.

Erich

 

[joaquins]

Hi joaquins

thanks for taking your time...

I uploaded LM 320-15 Datasheet and LM341-15 Datasheet on Dropbox. I found values for Vi on these datasheets.

Phantom values are: Supply Input - 47 Ohm - PhantomSwitch/ Mic Pin 3 to 4.07k and Mic Pin2 to  4.07k - PhantomSwitch

pdf Picure with Values is on dropbox.

Erich

Odd values for phantom, you should use lower voltage than 48V, I don't know exactly how much is standard for those resistors, or use 48V and change the resistors for 6k81 0.1% precision or 1% matched, so you get the standard phantom power. Most mics will work fine with less voltage and the resistors you already have, but they are designed for 48V 6k8.

JS