Do Vactrols actually work with ac LED drive?

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abbey road d enfer

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i read that ldr gives more distortion with more current through the ldr😑
Where? LDR are very linear, until they go into thermal problems (takes very large signals).
The LDR is not the main source of distortion, it's the variations of illumination that result from the side-chain timing. If the release time was infinite, distortion would be almost unmeasurable, even with very high level (+20dBu).
In more general terms, in a compressor, the gain cell (FET, vari-mu, optocoupler, VCA) usually generates less distortion than the side-chain, particularly at low fequencies.
So using it for attenuating higher impedance source signal may be cleaner? in place like after stepping up transformer before 1st tube of mic preamp
There is not much flexibility there because the LDR becomes very slow at low illumination.
 
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ruffrecords

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One thing to bear in mind is that the control voltage inevitably has signal content in it which will modulate the gain to some degree at the signal frequency (or twice the signal frequency if fullwave rectification is used) which will then be manifest as distortion. The faster the gain cell the worse this effect will be. The shorter the attack and decay times, the worse this effect will be. And of course the lower the frequency the worse the effect will be.

Cheers

Ian
 
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