vca fader and compressor

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

JAY X

Well-known member
Joined
Jan 9, 2009
Messages
683
Hi!

Attached to this message is a sketch of a fader/compressor schematic taken from the THAT design notes. My idea is to build a stereo fader with a simple compressor.  The controls are: Gain (volume), threshold, and  compression.  I will build it around a 4305 RMS detector and two 2181 vca's.

But a question arises:

If you combine fader volume and compression into a single circuit, the compression...¿is pre-fader?...¿post-fader?...¿in-fader?...¿what-fader? ???

¡¡Thank you for your advise!!

Jay x.
 

Attachments

  • volume compressor.jpg
    volume compressor.jpg
    318.6 KB · Views: 58
Hi Jay

Have a look at Studer 900 series schematic, there is a fader (VCA) with compressor

There is no pre or post here, all gain change, volume CV, compression CV, group CV drive the same VCA
You "just" need a CV summing amp from all source.

The audio SC for compression is taken before the VCA.

Best
Zam
 
Hi Zam!

¡Thanks for your explanation!. In any case, i see i can place an insert after the vca output.

Another question i have: ¿is it ok to sum the two sidechain signals L&R that enter the RMS detector?

Jay x
 
The SSL mix bus compressor is a combination of compressor and fader as well and it is pretty well documented here. Maybe this is good for inspiration as well?

Michael
 
Hi!

Thanks for all your advise! Now is time to design...and build... 8)

Jay x
 
Hi Again!

As always... too much enthusiastic... ;D

Revising the schematic, and other compressor schematics, i think it is possible to place a slew limiter, to add attack and release controls, after U3b, and then, the buffered output of the slew limiter goes to control the EC- control port of both vca's...¿right?

Jay x
 
Back
Top