MCI 636 EQ Mod

Hello all,

I have read bits and pieces about Modding the EQ section on a
J636 Desk and wondered if anyone could share any more then what I already have here.

Replacing the Mid and Top caps with Wima FKP-1 or MIT Multicaps.

Dropping the level going into the EQ by -6 db (anyone have a
good idea of doing this?)

I am adding about 12 John Hardy pre's into the board and would to mod the EQ as well. Any and all advice would be greatly appreciated.

Thanks!

Todd

could drop the level with resistors. value depends on input and output inpedence.... called a passive atenuator. Can find the calculator online and by inputting the impedence's of in and out and the amout of DB you wish to drop then will give you the resistors needed for balanced or unbalanced operation. Without looking at a console schemo would guess it's unbalanced.

here is a link

http://beradio.com/notebook/passive_attenuators/

Sweet!,
Thanks so much for the info. According to the link it looks just like
the same exact concept that I used here to make a couple
20 db Attenutation Pad Boxes to plug in here. So pretty much
in theory it's the same thing as padding the signal to a pre?
I can get a Scan of the EQ up here asap. But I am pretty sure its unbalanced.

I would lower the gain of the previous stage instead of padding. The pad will raise the input impedance into the EQ stage, so it may change the response of the EQ depending on the design.

Here is the link to the schematics:

EQ Module

http://echoesrecordingstudio.hypermart.net/MCI-600standard-eq.jpg


Input Module

http://echoesrecordingstudio.hypermart.net/MCI-600ch.jpg


Thanks again guys for all your advice :grin:

This is an older thread, but I'd be interested in your results, I'm recapping channels right now. Why drop the level? you'd just have to gain it up later on. I've never heard it crap out except with a really hot signal with a lot of EQ dialed. I only ever use the console EQ for little gentle pushes anyway, I patch outside EQs to get wacky. mostly I mix with the "chan" buttons mashed, it takes like 8 amps out of the path.

have you swapped the caps for different types? any noticable difference?

Also, sort of on-topic, I've been switching all my 5.5.3.4's to new j@pan r@dio chips. I can't tell much difference from the channels that were chipped with ph1llips, but they are definetly better than the Tejas chips. The low end in particular has gotten nicer.

The h@rdy pres are priced right but it bums me out to lock up great pres in an unmovable object... also don't count out the stockers! they are great, and with a little fiddling get even better. They use a LM394 supermatch pair up front same as the 990.

cheers