[sdiy] LM13700 as VC resistor

rsdio at audiobanshee.com rsdio at audiobanshee.com
Mon Feb 10 03:34:23 CET 2020

In addition, a VC resistor might be close to linear to start with, but if you try to lower the resistance using parallel resistors then it will definitely be quite nonlinear in response.

Of course, if you’re really lucky then you might want that nonlinearity. There aren’t too many situations where it works out perfectly, though.


On Feb 8, 2020, at 10:08 AM, Quincas Moreira <quincas at gmail.com> wrote:
> You can tune the LED brightness and use parallel resistors to get lower resistances as needed, but yes, LDRs are a bit slow to respond, so if you need high speed they are not ideal.
> On 8 Feb 2020, at 11:46, Didier Leplae via Synth-diy <synth-diy at synth-diy.org> wrote:
>> In my experience vactrols seem a bit hard to control and the resistances are very high. 
>> On Feb 8, 2020, at 11:39 AM, Michael Zacherl <sdiy-mz01 at blauwurf.info> wrote:
>>> On 08.02.2020, at 18:04, Quincas Moreira <quincas at gmail.com> wrote:
>>>> Here's the simplest VC resistor you can make, much easier than using an OTA!
>>>> https://youtu.be/8BOnvSQpoGY
>>> at the cost of speed, alas. 
>>> m.

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