Behringer Autocom MDX402 infos/schematic

[Gertius]

Hi guys,
I have an old mdx402 here that I´d like to get to know better and/or modify.
I already asked Behringer support for a schematic, but got no answer.

I really like the unit so far, it sounds quite clean, and is laid out very nicely.
It has THAT 2150 VCAs and 2252 RMS detectors, and TL074 opamps.
It seems to be the direct successor of the black/red studio compressor, having a very similar layout/components/sound (have one of those as well). I am wondering if it´s even the same, just without the black box hiding the internals.

It´s missing variable attack and release. I already tampered around with the time C on the 2252, changing it to peak detection (it seems to be configured for RMS, around 30ms) and the effect was quite drastic. Unfortunately that mod changed the release time as well, so it was distorting extremely. One idea was to put in a little board with a circuit for variable attack and release. Might it work to copy this part of the circuit from an SSL comp and put it in the 402, after changing the RMS detector to peak?

So, does anyone here have any more technical info on these, or schematics? (already checked the file section)

Cheers!
Christian

 

[Gertius]

anyone?

 

[analogguru]

If you can take some pictures I can tell you more.  I once ngooped and traced the black Studio Compressor (unfortunately without the display section) and it uses a 2150, a 2252 and some op-amps too.

BTW, the Studio Compressor is a 1:1 clone of the Audio Innovations RCL-50 Compressor, probably therefore the hiding of the components in the gooped box.

analogguru

 

[Gertius]

Hi analogguru,
wow thanks for your offer!
I will take pictures soon, haven´t gotten around to it so far.

Very interesting info with the Audio Innovations Compressor, I wasn´t aware of that.
So, would you have any documentation (schematics...) on the black studio compressor already?
As I mentioned before, I also have one of those, and I suspect the 402 not to be too different (if any).

Oh and another thing, did you see the pics you asked for of the mdx2000 daughterboard over in the "internal pics" thread?

Cheers!
Christian

 

[Gertius]

Hi analogguru,
I´ve finally gotten around to take some pics of the Autocom mdx402.
Please find them here:
https://www.dropbox.com/s/678a6rfw63fx9rt/Autocom.zip

Please note that this is a different guy than the one I´ve described in my first post.
I have a few mdx402s and they are all different. The best/oldest ones have THAT2150A and TL074, down to dbx1252 (like here) and BE037 and TL084 like in this guy from the fotos.
If you need anything else, please let me know!

Really looking forward to see what you can find out!

Cheers,
Christian

 

[s2udio]

Just replace the TL074'S With TLE2074 ...give it a recap and leave it there ,no point in going any further
As you wont improve it any more than that.