Tremolo Effect

Hi everyone, I have been working on a tremolo effect for a university project. it's an old R A Penfold design. I have breadboarded from the schematic but used a 2m2 Log pot instead of a 2m2 Lin as I could not get hold of one of these at my local electronic outlets.

Does RV2 control the rate or the depth?

When I tested it earlier I could hear a slight tremolo effect but nothing like I expected. Could this be caused by the log pot?

Cheers Stu

Looks to me as if RV1 is depth and RV2 is rate (IC2a & IC2b are the oscillator).

It should work equally well with linear or log pots, so you must have made a mistake somewhere.

I always believed that the CD4007 part was obsolete. TI has a data sheet revised on 2003. (!)

Hi, I purchased the CD4007 from Farnells. I went through the breadboard again and had it checked over by a friend who seemed to think it was correct too. I played it again through some rokit krk6's as I thought it was possible the speakers I was originally testing the circuit on didn't cover the lower end audio bandwidth but still you could only hear a slight stutter. I have changed the chips and checked over breadboard enough times to know its correct. Any ideas?

Isolate the problem.
Check the AC voltage on pin 1 of IC2.
Than disconnect the 47k pot from pin 1 and connect it to +9V. Vary the pot and the FET should act like a volume control.
Replace the FET with the other 2 in the package or go to a discreete (2N5460?)
E

could it be because it is created on a breadboard. Breadboard's have a high capacitance so audio circuits are not very good when made on them. High frequency oscillations occur along with other noises such as picking up radio signals

also check all your component values are correct and your power supply has little noise on it

a log potentiometer is the same as a linear but it has a different movement direction so that isn't the cause of the problem