Slightly O.T. -- tremolo pedal

Posted: 9/5/2010 11:33:42 PM

Joined: 9/12/2009

So I designed, built, and beat-it-until-it-worked (otherwise known as "debugging") this tremolo pedal.

Tried it on my guitar tonight for the first time. UGH... sounds great but the oscillator is bleeding into the audio path. There is this annoying tick, tick, tick that varies with the Rate setting.

Tremolo effects like this run 3Hz to 13Hz, typically. Mine will go out to about 30Hz, not that it is useful at that rate.

Unlike off-the-shelf pedals, this one is unity-gain, well actually it has a slight bit of gain that can be trimmed down so that the in-circuit/bypassed levels are the same. If someone did want to use a tremolo effect with the typical theremin, this would work great ... once I get rid of that ticking ...

Anybody have any suggestions on filtering out the ticking?
Posted: 9/7/2010 11:32:33 AM

From: Escondido, CA

Joined: 2/6/2008

I did manage to reduce the oscillator bleed-thru to an acceptable level by bridging 47pF across the feedback resistors of the 2 amp stages.

Next spin I will use separate opamps! But I do have a nice-sounding tremolo circuit if anyone's interested.


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