Author Topic: Quad comp key input  (Read 126 times)

MarconeMusic

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Quad comp key input
« on: November 04, 2018, 04:16:06 AM »
Hey

Been a while. Probably because shes working quite well since shes been back in action.  :)

Curious.

Im assuming theres no key input to the quad comp on the 4000 consoles.
Does anyone know of a mod that could potentially be done to the back buss to have it as a route to a key input, yet leave the front buss alone for normal use?

Just wondering for keying mixes with an eqd copy for mid range fun.

Cheers!

amillar

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Re: Quad comp key input
« Reply #1 on: November 09, 2018, 10:27:25 AM »
Surely that's got to be possible? I'm away at the moment with no access to the manual but I'll have a look next week if no-one else comes up with an answer.

Fun idea  :)

Andy
co-designer and project manager G series analogue 1987
channel strip designer J series 1992-93
design "caretaker" 4000/6000 1985-93
analogue team leader ARC/Bertha 1988-92

MarconeMusic

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Re: Quad comp key input
« Reply #2 on: November 11, 2018, 04:13:44 AM »
Andy, That would be amazing if you had an idea towards this. :)

amillar

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Re: Quad comp key input
« Reply #3 on: Today at 12:23:03 PM »
I'm assuming that your problem is not how to key from the back bus (which you can do by simply routing the key signal to the back bus, but not using the back bus output of the compressor / main fader).

I'm assuming your problem is how to stop the front bus also keying the compressor while you are keying from the back bus? Ok, the way I would do this (I think) is to cut the link between pins 17  of the '26 cards on the 651 backplane between the front and rear cards. So the front cards are still linked, and the rear cards are still linked, but the front and rear are seperate. Now you'll need to find another switch! The existing compressor In/Out switch will switch in either the front or rear compressor key input (I don't know which, it depends which pair end up connected to the switch after you've cut the track!), then you can wire a new switch to the other two pins 17 with the switch pulling up to +18V and the lamp pulling down to -18V. (The pull down to -18V isn't essential, R28 on the 26 card should do it anyway.) This should make sense if you have a 26 card circuit.

Now, assuming your main signal is going through the front bus, your signal can be keyed by either the front bus, the rear bus, or both depending which of the switches you press (or both together!). Or off if both switches are off.

Hope that make sense, it's hard explaining in text!

Post here if you get stuck  :)

By the way, this  will invalidate your SSL warranty  ;D

Cheers,

Andy
« Last Edit: Today at 12:30:44 PM by amillar »
co-designer and project manager G series analogue 1987
channel strip designer J series 1992-93
design "caretaker" 4000/6000 1985-93
analogue team leader ARC/Bertha 1988-92