Cgs synth

>So, I am wondering what parts others have used. According to the
>instructions, I should be using a low leakage cap. These may not
>quality. So, I am thinking I will change all my Cx out to 100n to
>200n range and use polypropylene. Any experience anyone has to offer
>will be appreciated.

Also perhaps changing op-amps will help. Find an op-amp with higher input
impedence than the one used.

>Next, my initial observation is that a negative voltage at the input
>is not going to work at all. Any others care to comment?

It will work. Sure, the analog switch is operation in the positive area
only, but that is what those funny op-amp buffers are their for - they
recuce the range of the input switng, and center it around 7.5V. This also
in part contributes to the faster droop rate, as it is amplified when the
range is restored at the output.

>My next question conerns the imput impedance. Is there any specific
>reason for the 22K input to TL074d? Does it not make any sense to
>raise the value of the two 22Ks and apply the same percentage
>increase to the 10K feedback resistor to have a higher input
>impedance load on sensitive voltages like 1v/oct control? I dunno.
>That's why I ask.

Increase the resistors if you like, but keep the ratios exactly the same for
the above reason.

Ken
_______________________________________________________________________
Ken Stone sasami@...
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