[sdiy] bergfotron measurements Replacing CA3080 with CA3046 ??

[karl dalen]

Another thing,

Bergfotron says that the serge vca distorts badly,
i sugest that it does because it are forcing to much 
input bias current to the 13600, also the inputs are 
pulled far to low so the input trannies are on the edge
to flattening out ,working in the non linear area, perhaps 
a change to 56k, 68k will improwe!

Also the output buffer are wrongly conected! And should'nt the
input resistor go directly to the + or - pin instead of going trough 
the bias resistors? I find the conection a bit strange!

Also in your S/N figures do you include the Iabc noise generated
by the expo? The Iabc current gets directly translated into voltage 
noise and at measuring levels of 90db and above this will indeed 
show up in the measurements.

Final, the substrate in the 4046 VCA is only to gnd in most cases
it souhld be biased to the cirquits lowes potential, wich is not GND.

Reg
KD