need more inputs & outputs to run tape machines

swampwalker has the right idea.

I wonder though if it would make sense for you to all-our on a 16-20 channel mixer (mackie makes some great ones) unless you think that you'd benefit from adjustable level, gain and EQ per channel.

One thing I think I would consider is making my own.  If I understand your ultimate setup, you'd have 20 stereo inputs and 20 stereo outputs on the tape side but only a single input and single output on the source side. In other words, all 40 I/Os would be wired in parallel.

Theoretically you could build one pretty easily (project enclosures are easy to come by as well as all necessary parts) and I think I would forego any switching capability to simplify the build - Of course that means that all inputs and outputs would be active all the time, which might be handy for you.

It's interesting that you're looking for such a solution since I don't think I've ever heard of anyone needing to do this (unless you're in the tape duplication business) which would explain why there isn't an obvious off the shelf solution

Good luck

Greg

I don't think 2 of those would work the way you're suggesting as one box would have 8inputs and one output and the other one you would set up with 8 outputs and one input - i don't that that gets you where you need to be.

As far as the professional mixing consoles go, that would absolutely give you all the functionality and routing options you need, but unfortunately all of them are either XLR or 1/4 inch TRS connections and I assume that all of your gear is RCA?  I suppose that you could get a bunch of RCA to 1/4" adapters, but that would feel a bit hacky.

Personally I would go the DIY route since it's such a special application and forego switching (as I suggested earlier) since it would add to the complexity, cost and probably degrade sound as well.

I suggest putting together a parts list and contracting someone to put it together for you - I would estimate that you could probably get something parts and labor put together for under $1K without much difficulty.

Good luck and keep us posted on what you come up with.

Greg