Simple transistor tremelo.

[jbm222]

I want to build a very simple tremelo using 2N3904s and/or 3906s.  My goal is to elimante opamps and LED/LDRs completely.  I'm thinking the best way to be find a way to vary the gain of a single 3904 amplifier, but I don't want to use an LDR to do it.  Will putting a resitor at the 3904 emmiter and oscillating the voltage at the other side of it (the resistor) acheive this?

Any other ideas?

[smashinator]

Have you taken a look at the EA Tremolo?  You can check it out over at www.runoffgroove.com

[lightningfingers]

Use a phase shift oscillator to vary the signal level.....

I'm thinking the best way to be find a way to vary the gain of a single 3904 amplifier, but I don't want to use an LDR to do it

You could use a 2N3904 as a variable reistor.

[dosmun]

I built the EA Tremolo and it is very easy and sounds great.

[casey]

theres one called p.e.t. (pretty easy tremolo)  - is this a j. davidson design?  i cant remember...but it's super easy to build.

[jbm222]

I found a schematic for the P.E.T.  I think I have all the parts for it except the 1M pot, so i think I'm going to mess around with one of those.

[Transmogrifox]

I would put one more up for the EA tremolo.  It's a pretty straightforward design.

[Mihkel]

I found a schematic for the P.E.T.  I think I have all the parts for it except the 1M pot, so i think I'm going to mess around with one of those.

Could you provide a link to that schematic?

Thanks

[Ge_Whiz]

Isn't there a schematic somewhere for a 'Walco' tremolo using all bipolar transistors? Can't find it at the moment.

[Paul Perry (Frostwave)]

www.guitarraonline.com.ar/lapedalera/pet.htm
I googled for "pretty easy tremolo" :wink:

[casey]

NICE!  

[Mihkel]

I ran that site through Google translator and got a pretty funny translation:

The usual thing:
1 double investing key of pulser
2 jacks of 6.5mm (one stereo and another monkey)
Paper clip of bateria
Jack of transformer
Plate of pertinax, percloruro, tin, etc.
Cable

[onboard]

Aw cripes, another monkey! My monkeys are all gone...

Seriously, the p.e.t. looks much easier than the EA. Man, hats off to Joe's circuits. Is the EA circuit over engineered, or just different?

Made any progress jbm222?

[TheBigMan]

Fuzz Central has a layout for the Colorsound Tremolo as well.  It uses all bipolars.