Discrete console Re-design (allen & heath sd12-2 and allen & heath quasi)

[Vyvyan]

alright, I have some plans to rework my allen & heath boaeds (sd-12-2 and quasi) i have all the parts to replace the two transistor transformerless mic amp with an input trans and 3 transistor amp the orginal pcb has a 741 chip post eq/pre fader, I plan on replacing it with a 2520 amp (power supply in using is linear, +/- 24v 5a).

any sugesstions? am i crazy? ive combine all the pieces into one schematic below.

 

[Khron]

So you plan on adding a separate power supply just for the 2520's (one per channel)? In the hopes of achieving what, exactly?

Just be aware you'll also likely need to add some DC-blocking capacitors at the inputs, as well as separately biasing them.

 

[Vyvyan]

using a seperate external supply for the entire board which has a -24 rail. already have a few channels working with the above idea 9 tho the 2520 configuration is a bit different, i forgot to edit the configuration above.4 channels are as above and 4 more channels as above but with altec 1588B mic pres replacing the pre above and 4 more are in the works with 2520s as mic pres and post eq makeup with interstage transformers replacing coupling caps. theres no real goal, i just have a surplus of parts and wanted to build a little tracking/mixing console with all my best parts. i even squeezed an inductor eq on the master channels and a built in spring reverb pulled from a peavey pa900 [which im also currently modding] with sends on each channel. the pa900 is actually pretty fun looks like an old tube 610 console and is discrete and funky just as i like it! still evaluating its schematic and trying out different cap values. heres a pick and the schem for that project.