Midas XL4 Equalizer

[dominick]

Hello,
Long story short I this this desk is a case study for good design (as far as the user is concerned) and am very interested in whats going on under the hood.

Specifically, I'm looking for some information on the EQ section. The service manual just shows two black-boxes, the KTR014/15. I'd like to be able work out the circuit beyond the vague idea that these are dual quasi-universal filter blocks. And in the sort of simple cookbook SVF style that I imagine they would use.

If you have some information, or access to a channel strip and could show what the component side of these cards look like, it would be most helpful.

Thanks!

 

[j.colt]

The XL3 should have the same two mid bands as the XL4. I think the only difference is the parametric high and low band. The full schematics for the XL3 is here: http://pdf.textfiles.com/manuals/STARINMANUALS/Bosch - Midas/Manual/XL3 - Long.pdf I have 8 channels of an XL3 racked but not at all accessible right now sadly... there was an interview of the designer in SOS a few years ago and there might to be some voodoo in this seemingly simple EQ design.

 

[jensenmann]

You can find the XL4 service manual here in the schematics section: Data – tradefair.audio