[sdiy] SIP filter modules coming

[KD KD]

> Yeah, ok. Maybe “stupid” is a bit strong. But I’d much rather have had an
> op-amp there instead, even if it was only a 741-type thing. Then you could
> have done a unity-gain follower for your OTA Cap-to-ground style filters, or
> an inverting integrator, and you’d also be able to implement a proper I-to-V
> stage for VCA applications, which gives a much better result than a resistor
> to ground followed by the buffer.

> Anyway, I can see why Alfa left them off. Many, or even “most”, designs with
> the 13600/13700 seem to leave them out. I only really see them used in
> stompbox circuits where minimal parts seems to be a more important design
> objective then overall quality.Tom!

A FET tranny will do wonders, anyhow of-course i concur it would be nice to have
proper buffer but if you look into the SDIY archive you will find when
Harry Bizzell
sorted out the difference between 13600 and 13700 buffers and why.

What we wanted is the 13600 buffers high beta auto bias but without CV
shift poping but instead we got low beta 13700 buffers.

You have to go way back in time to see lots of buffer usages but thats
with 13600.