[sdiy] BBD findings 2

[JH.]

Browsed thru old Dynacord schematics.

Did you ever wonder why the (older) SRS-56 sounds so much better
than the VRS-23 ? The use the same BBD chips, and very similar circuitry,
after all!

I don't claim I have the answer, and with BBDs even something like the
mechanical construction can make a difference (route of GND and
supply voltages, etc.). But I noticed something remarkable which
I hadn't seen before:
The SRS-56 and VRS-23 use a very similar clock driver circuit,
except that the SRS-56 has the "Gap" adjustment, while the VRS-23
just uses 50% pulses. (unless there's a drawing error, which it might
be: the VRS-23 still uses the paralleled NAND gates before the
discrete totem poles, but here they are connected as simple inverters!)

JH.