[sdiy] Re: analog switch ICs

[Paul Higgins]

I know that there's the issue of charge injection, something that one 
of the LDR/Vactrol-type manufacturers (I forget who) is always saying 
about FETs.  So, naturally, making it an opto-FET gets you total 
isolation between the control circuit and the signal.  But I don't 
think charge injection is a big deal when things are changing smoothly, 
like an LFO.  Maybe with abrupt control changes like a compressor or 
noise gate.  And even then, I don't hear lots of people complaining 
about pops and clicks in the old FET compressors like the Urei 1176.

I think it's doubtful that there's any advantage for the H11F1s, but 
then again, I've never tried it.  I'm pretty sure that Paia was 
shipping them in some of their stuff as a replacement for the CLM6000s 
in all those old Craig Anderton circuits.  Of course, in those 
circuits, you have to use the H11F1s or else do a complete rework of 
the entire circuit.

-PRH

On Friday, May 7, 2004, at 10:08 AM, jhaible at debitel.net wrote:

>> I can start on the phaser using the H11F1.
>
> Is there any advantage over ordinary FETs
> in a phaser application?
>
> JH.


Paul Higgins
email: higg0008 at tc.umn.edu