[sdiy] DIY Mixer - please help!

[cheater cheater]

Hi guys,
It has come so far that I can't go on without a mixer, and, well,
nothing I see on the market is satisfying to me right now. This can be
of great use for modular synths as well since I would want it to be
fully CV controllable. This is in part propelled by the fact that I
have bought a TX816 which will need a proper mixer in order for me to
be able to use it at all.

I am currently collecting ideas as well as resources. It seems as
though it's not so easy to find the schematics for most mixers that -
at least I consider - are interesting. The first step is to come up
with a good summing bus design. I think solid state is good for a
start, but since it's all DIY, it'll be possible to swap it out for a
tube stage if there's a need for that.

I understand this list might not be the best forum to find out about
this stuff - but I searched about for mixer/console DIY with people
who actually *knew their stuff* when it comes to analogue music
hardware and I simply couldn't find much interesting. If anyone has
any recommendations, please do tell me. I trust the people here so I
ask you guys first :)

Here's a quick writeup of what I have in my brain right now. Most of
it is probably wrong, so please correct me.

What I am thinking of is a simple but effective modular approach which
consists of:

1) multiple summing busses
2) multiple VCAs

Each channel is one VCA that has CV inputs, a single input, and a
single output to a single bus. Of course a stereo channel is that
multiplied by 2. With a CV approach it's going to be very easy to
control two channels with just the fader of the left channel, but
that's a trivial comment.
The bus sums and gives a single high-headroom output.

The first thing to do is to make a good summing bus. I understand that
to do this I will need to come up with a good op-amp design. What I am
looking for is good headroom. Can someone recommend anything good?
Supposedly the Harrison 4032c is pretty good. If you guys have heard
the headroom in MJ's 'Thriller' - that's that. Has anyone got leads on
that?

As far as the mixer's format and general set of abilities, I am
inspired by things like Manley mixers (EveAnna many positive
affirmations to you if you can read this) and Chandler Limited (but a
little less so because I haven't spoken to Mr Chandler or Mr Limited)

I find that a fully voltage controllable design could be useful. For
example a feedback compressor could be built which outputs CV that
will be fed into the VCAs. Therefore the whole signal chain from the
sound source to the recorder could be just two VCAs - I guess that's
better if someone's looking for this sort of thing.

Is there some interaction between the 'mixer strip' and the summing
bus that I have left out? Or is my concept of how a mixer should be
designed just plain wrong? :)

Thanks guys
Damian (probably wrong)