No subject

there are 3 added resistors (all 47k) and one capacitor (8.2nF), that =
form a
symmetric attenuator and low-pass filter (412 Hz). This means that the =
VCA
input in the original version is about 10 dB higher at low end, and 30dB =
at
high end.=20

The other difference is the percussion output filter (components between =
P
and D terminals): The original design has both low-pass and high-pass
circuits, the new one has only high pass. The old high-pass has 2 =
stages,
the new one has 3. And the old low-pass creates the percussion taper =
AFTER
the VCA, compared to the new, where the taper is created BEFORE. These
differences in levels and filtering surely make differences in sound: =
the
old one distorts easily (at least in theory), but the high-order =
harmonics
are filtered out. The new design is a lot cleaner than the old. Maybe =
there
are differences in frequency responses too.=20

I have not compared these circuits by listening to them side-by-side. =
And my
'73 B-3 has the AO28-3 preamp: no input attenuator in the VCA and a =
little
bit different capacitor values between P and D terminal (and 3 stage of
high-pass!). As this is not documented in any service manual I have =
seen,
I'll send the values here:=20

'73 B-3 with undocumented AO28-3 preamp