[sdiy] LM13700 as VC resistor

[eidorian at aladan.net]

The prodigious and awesome Gieskes uses H11F1 in the 3trins, for voltage 
control over a video-frequency schmidt-trigger based oscillator.

https://gieskes.nl/instruments/?file=3TrinsRGB1

https://gieskes.nl/

Cheers,
A.

---


On 09-02-2020 12:21, Didier Leplae via Synth-diy wrote:
> I searched a bit in the archives, but didn’t find anything.
> The H11F1 sounds interesting. I will look into that.
> 
> 
>> On Feb 8, 2020, at 12:05 PM, music.maker at gte.net wrote:
>> 
>> 
>> 
>> This has been bugging me because I seem to remember a thread here 
>> years ago.  I can't
>> remember what the outcome was, but maybe a search of the archives (for 
>> which I seem to have
>> no foo) might find it.  I do remember it was regarding the datasheet 
>> circuits mentioned by
>> the OP.  Generally, the feel I think was that under the right circuit 
>> circumstances, it can
>> work like a VCresistor.  I remember that the vactrol was compared and 
>> is known to work
>> properly as a floating VCresistor albeit slow to change value.  Not an 
>> EE here, but looking
>> at the floating resistor circuit I see two current producing 
>> electrodes posing as a
>> floating resistor.  I think generally the statement about it's lack of 
>> use in synth
>> circuits is due to it not being very good is probably correct.  
>> Looking at the single ended
>> circuits, they are AC coupled...
>> 
>> Has anyone experience with H11F1 devices?  Those should be a lot 
>> faster than vactrols,
>> probably more consistent, but I don't know if the transfer function is 
>> useful in
>> audio/synth circuits.
>> 
>> -- ScottG
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> 
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