[sdiy] Looking for layout opinions

[David G Dixon]

Hi List!

I'm in the process of laying out one of my circuits (actually the Rubicon 2
TZFM VCO) for through-hole PCBs and 5U construction.  I am nearly done with
the layout, but I've come up against a conundrum, and I wanted to get some
outside opinions.

The circuit layout will have to be on two separate PCBs, which I've managed
to limit to 4" x 6" each.  I've got the main tricore VCO circuit and TZFM
circuitry all done on one PCB, which is completely crammed.  All of the
waveshapers, suboctaves, Warp, and Squish will go on the second board, which
is not quite as crammed.

So, here's my issue:

The entire circuit requires 12 VCAs (three 2164 chips).  The main VCO
circuit requires 10 VCAs and the Warp circuit requires 2 VCAs.  However, the
Warp circuit is on a different PCB.  I have actually put all three 2164
chips on the main VCO board.  However, there is plenty of room on the shaper
board for another 2164 chip.

So, here's what I want your opinion about (sort of a "What would you do?"
kind of thing):

Should I:

1) Lay out the 2 Warp VCAs on the main VCO board and connect them to the
shaper board with wires, thus splitting the Warp circuitry between two
boards?

Or, should I:

2) Use a fourth 2164 chip on the shaper board, only 2 VCAs of which will be
used, thus keeping all the relevant circuitry on the same board (and wasting
the equivalent of one entire 2164)?

My inclination is to lay out for both possibilities and let the end builder
decide how to handle it, but that seems kinda stupid.  I'm curious what
y'all think.  The cost of doing the second option is about $5 (chip plus
socket), so it's not exactly a life-or-death decision.

Cheers,
Dave Dixon