need more inputs & outputs to run tape machines

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

To the OP, what are you doing?  Why would anyone want to connect 15 or 20 tape decks to a consumer class integrated amp?  Please explain.

onhwy61, I have a collection of reel to reel tape recorders & want to be able to use any one when desired.I have been collecting them for over 45 years.

I have similar issue as the OP.  I am considering the use of Y cables to split the signal, but I am concerned about the effect that may have on the quality of the signal.  The switch box one post links to is probably no better than the old Rat Shack boxes (I use one currently).  I am also thinking of using an old receiver with multiple tape loops as a (very large) input switcher.  Again, though, the concern is signal degradation.

FWIW, Morrow offers Y cables at many price points that might work.  I may go that route myself.  

Your amp has three full tape loops.  Why not use long interconnects and have 3 tape decks hooked up at a time?  When you want to switch to a different deck simply switch the cables at the tape deck end.

Alternatively, you could use a Niles or Sony tape deck switcher.  Each allows you to hook up 3 tape decks to a single tape loop.  If you got three of them you could have 9 tape decks simultaneously connected.

Good luck!