[sdiy] Something better than CD4066 to switch CVs?

Michael Zacherl sdiy-mz01 at blauwurf.info
Tue Feb 19 19:17:57 CET 2019


> On 19 Feb 2019, at 19:09, chris <chris at chrismusic.de> wrote:
> 
> On Tue, 19 Feb 2019 18:35:44 +0100 Florian Anwander <fanwander at mnet-online.de> wrote:
> 
>> Am 19.02.19 um 11:06 schrieb Tom Wiltshire:
>>> The Prophet 5 managed to switch Oscillator B into low frequency mode about thirty years ago, so it must be possible.
>>> 
>>> I had a look at the schematic and it doesn’t look like they switch an extra cap in though. Instead they switch an extra -15V into the CV. The Pro-1 uses the same trick.
>>> 
>> Someone more knowledged may correct me, but I think this may work with a 
>> coarse parameter change, but with tracking sensitive controls, the inner 
>> resistance of the 4066 might become an influence.
>> 
>> Florian
> 
> But once you're entering LFO range, IMHO tracking becomes less important.
> And I don't think an *open* switch will affect audio tracking.
> 
> I agree that using a CMOS switch in tracking relevant areas requires at
> least some consideration. Switch resistance may be specified as foggy as
> "yes, it's there, and it's something around ^&@&%* ohms at room
> temperature”.

The Cyndustries Zeroscillator used reed relays to switch the capacitors.
That was some 14 years ago.

m. (boy, that’s quite some time!)




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