Simple Tremolo

[CynicalMan]

This is my attempt at designing as simple a tremolo as possible. It has an LFO (based on the pulsing LED LFO by Darren Inwood and Rob Strand) that I got from Tim Escobedo's Wobbletron and then tweaked a bit. I designed the LFO buffer and modulation stages. The depth pot has a large range, going from glitchy throbbing tones that are very fun to play around with, to nice moderate tremolo, to very little tremolo.

http://www.aronnelson.com/DIYFiles/up/Simple_Tremolo_Demo.mp3
Bypassed - max. speed - med. speed - min. speed - max. depth (glitchy!  ) - min. depth

Edit: If you don't want to have any of the glitchyness in the range of the depth control, put a 10k resistor in series with it.

[darron]

i love tremolos and i'm really into them right now. very cool project that you have taken up! nice efforts.

tremolos are less subjective than distortions and stuff. they all sound good minus the stuff you don't like about them. the only thing that I can really pick at is that it sounds like it has a small hump in the wave. For example, if you set it for something reasonably deep and slow you hear that the wave sit at almost zero for a tiny while, then ramps up and down and sits at zero for a little bit again. that's often what people have to do if you want to get really deep settings though so that might be good too.

posting a sound sample with a schematic is the best thing ever! it helps out people who are not like R.G. and just look at the components and say "it sounds like this" as though it were music manuscript hehe. jk R.G.

[soggybag]

Seems you could simplify this even more by using the FET drain to source as a path to ground at the output. As the gate voltage increases more of the input would get shunted to ground.

[CynicalMan]

Seems you could simplify this even more by using the FET drain to source as a path to ground at the output. As the gate voltage increases more of the input would get shunted to ground.

The depth and volume cut would vary with the output impedance of the previous stage. If I wanted to avoid that, I would have to add a buffer and resistor before the FET. Also, it's often nice to have a bit of gain with a tremolo.

[ayayay!]

I think that glitch is cool!  I love how simple the circuit is.  I've been reading up a lot on tremolos.  This is a great simple project and the clear schem sure makes things easier to understand!  Nice work! 

[CynicalMan]

Thanks!

Darron, changing R8 to 47k helped the problem you mentioned. I probably just had Q1 biased too low and it was clipping the bottom edge of the LFO wave.

[CynicalMan]

So far I have tested this with a couple of amps. With an Orange practice amp, there's a little bit of LFO throb that you have to turn up to hear. I just tried it with a Line 6 spider 3 amp and there's a loud ticking sound that is in sync with the LFO.