cgh00
New member
Hi, thanks in advance to anyone who reads this
I've built a tremolo circuit on a breadboard for a guitar pedal, but can't seem to get it working right. I've used the attached images (thank you to the original creators) to come up with the effect:
I built it on 2 breadboards as the ones I have are really small - 1 board for the lfo and power supply, 1 board for the input/output, Q1, and amp part of the circuit. The LFO works but right now it's only turning and LED on and off and not opening and closing Q1. The datasheet for the MAX1044 (IC2) says it can only put out about 20ma max. so I tried a higher resistor on the LED and removing the LED from the circuit completely, as well as a smaller resistor at the base of Q1 but it doesn't make a difference.
I can't explain this but when I remove the ground connection from the 2nd board (with Q1, Q2, R10-R15 etc.) the effect starts working but with a horrible amount of noise (see the attached sound files).
Voltage at the base of Q1 is -7.2V - +0.7V when the emitter is connected to ground, and -6.2V - +3.4V when the emitter is disconnected from ground. Base current of Q1 is -3mA - 0mA when emitter is connected to ground, and 0mA - +0.4mA when emitter is disconnected from ground.
So I guess that the sound passes through unaffected because the Q1 base current is too small, but why does it work (albeit with a lot of noise) when there is no ground connection to that part of the circuit? Maybe because there's ground from the input + output jacks? And any idea what's going on with the LFO output?
P.S. you can probably tell I'm not very good with electronics, sorry
Ground connected:
View attachment Ground_connected.wav
Ground disconnected: (You can hear that the controls of the tremolo are working)
View attachment Ground_disconnected.wav
I've built a tremolo circuit on a breadboard for a guitar pedal, but can't seem to get it working right. I've used the attached images (thank you to the original creators) to come up with the effect:
I built it on 2 breadboards as the ones I have are really small - 1 board for the lfo and power supply, 1 board for the input/output, Q1, and amp part of the circuit. The LFO works but right now it's only turning and LED on and off and not opening and closing Q1. The datasheet for the MAX1044 (IC2) says it can only put out about 20ma max. so I tried a higher resistor on the LED and removing the LED from the circuit completely, as well as a smaller resistor at the base of Q1 but it doesn't make a difference.
I can't explain this but when I remove the ground connection from the 2nd board (with Q1, Q2, R10-R15 etc.) the effect starts working but with a horrible amount of noise (see the attached sound files).
Voltage at the base of Q1 is -7.2V - +0.7V when the emitter is connected to ground, and -6.2V - +3.4V when the emitter is disconnected from ground. Base current of Q1 is -3mA - 0mA when emitter is connected to ground, and 0mA - +0.4mA when emitter is disconnected from ground.
So I guess that the sound passes through unaffected because the Q1 base current is too small, but why does it work (albeit with a lot of noise) when there is no ground connection to that part of the circuit? Maybe because there's ground from the input + output jacks? And any idea what's going on with the LFO output?
P.S. you can probably tell I'm not very good with electronics, sorry
Ground connected:
View attachment Ground_connected.wav
Ground disconnected: (You can hear that the controls of the tremolo are working)
View attachment Ground_disconnected.wav
