DIYers love and HATE dream...MCI 500

I have a JH532C and JH636 consoles... I can build custom vca's that use the Analog Devices vca chip to replace the DBX202c's that most of them have. They can be trimmed to around .007% THD. It's like taking the blanket off the speakers. I can build them for around $20 each. All you have to do is remove the DBX Vca change 4 resistors on the Mci vca board, install the new VCA module and your ready to go.

Currently, I'm out of blank circuit boards...I checked recently on getting more made and it was going to be around a $500 investment . I can supply the circuit board artwork and schematics to anyone whose interested, but you will need a distortion analyzer and a test fixture to adjust them.

I made my test fixture out of a JH600 automated fader circuit board.

Also, you can add massive amounts of capacitance to each of the 4 rails on the 500.On the frame you'll find caps of about 3300 mfd on each of the audio rails plus the 24v lamp and relay and 5v logic rails. I installed around 100000 mfd on each of the audio rails: +/-32 and +/-15.
Really helps with headroom.

Also, I built a custom summing amp section for the Master and Monitor Module using Forssell JFET 993 discrete op amps.

This is a capture off an 80's camcorder showing the rotatable 500 i/o module jig that I made back in the day.

The big square button on the left was the master power switch.
Very handy!

I need some more help on MCI 500 desks....I would like to know diference in C and D models...also I have model D and schematics for Model C ...

anybody out there have schematics for model D??????