Convert Tube Mixer / Direct Outputs

Archived from groups: rec.audio.tech (More info?)

Andrea Zavareei wrote:

> Hey all. I have a Bogen 5 channel tube mixer that I want to modify. I
> understand a summing amp doesn't actually add any gain, it just summs.
> I'd like to take 4 of the channels and give them each a direct output.
> I don't have a schematic( I tried!), but it seems like they each go
> from the input, to a transformer to a tube(2 channels share one tube,
> which I beleive is normal as they have two sections each) to a fader,
> and then I think the summing amp. Could I just tap into them post
> fader to get direct unbalanced outputs at line level? From what I've
> been told this should be pretty easy. And perhaps use a switching jack
> like in a patchbay, so that without a plug in the direct out jacks, it
> would be normalled to the summing amp. Anyone have any ideas? Thanks!
I used to own a Bogen Mic Mixer (LM I think). They actually have quite
a bit of gain, I used it to drive power amplifiers -- which in the
early 70's were not that sensitive.

Your best bet is probably to tap off of the inputs of the individual
level controls.

Mike McGinn
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Mike McGinn