Six Channel Audio Mixer Output Question

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Chris Willocks
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Six Channel Audio Mixer Output Question

Post by Chris Willocks » Wed Mar 25, 2020 5:26 pm

Hi everyone,

I've designed the following, simple six channel Eurorack audio mixer:

Six Channel Audio Mixer.png

It has two simultaneous outputs i.e. that can be used at the same time. However I'm not convinced that having them both split off the same op amp is the best way of doing this? Would this design work, or would there be a more optimal way?

Many thanks,
Chris
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Re: Six Channel Audio Mixer Output Question

Post by guest » Wed Mar 25, 2020 6:00 pm

that should work. one downside to sharing the 10uF cap at the output, is that if one of the outputs gets shorted, the signal on the other loses some of its low end. this wont be dramatic, as 10uF/1k gives a 3dB point of 16Hz. and be sure to use a 50V or better rated cap. if the output is pulled high for some reason, you could end up with a decent reverse bias on the polarized cap. higher forward rated caps can also withstand higher reverse voltage. the 1k resistors will keep the cap from being permanently damaged or exploding under the reverse condition.
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Chris Willocks
Learning to Wiggle
Posts: 8
Joined: Mon Dec 09, 2019 1:09 pm

Re: Six Channel Audio Mixer Output Question

Post by Chris Willocks » Wed Mar 25, 2020 7:11 pm

Thanks for the feedback.

Would it solve the issue of losing the low end by giving each output its own dedicated 10uF cap, rather than have both sharing the same one?

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Re: Six Channel Audio Mixer Output Question

Post by KSS » Wed Mar 25, 2020 10:19 pm

Unless you've got a specific piece of gear you're accomodating with that output cap, I'd just leave it off.
Caps on inputs -where needed or desired. Resistors on outputs -except V-Oct CVs

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