Proposition Distortion Low output.

[Causefarley]

Hey guys! My build doesn’t seem to have vert much output. I am worried I have a short somewhere because for some reason I can inject a signal through the case of Q1 and C6. Has anyone ever come across this?and has anyone posted the voltages for this? Thanks y’all. I will get some pics up asap.

 

[jesuscrisp]

Not sure what you mean with the Q1 and C6 thing, but chances are you have a wrong value somewhere.

 

[Giorfida]

Hey guys! My build doesn’t seem to have vert much output. I am worried I have a short somewhere because for some reason I can inject a signal through the case of Q1 and C6. Has anyone ever come across this?and has anyone posted the voltages for this? Thanks y’all. I will get some pics up asap.

How low is your output? Are you able to at least get unity gain (same volume as bypassed)

 

[Causefarley]

No sir I cannot get unity gain. When I am using my signal tracer if I touch the case of the transistor or the case of c6 I hear the signal.

 

[Giorfida]

Maybe try reflowing the solder, especially around those components. Sounds like you are touching them they are making contact, but when not they don’t.

 

[Causefarley]

10-4 I will do that. Thanks guys! Hopefully I can report back as solved.

 

[Cybercow]

What are the DC voltage readings at pin 8 of the opamps? And what is the voltage reading at pin 5 of IC3?

What specific JFET is being used? And what are the values of RB1 & RB2?

Also, how securely is the JFET seated in those sockets? To counter any issues with sloppy socket connections, I gently 'wrinkle" the ends of the legs.

 

[Causefarley]

Working perfectly now! Turns out it was a bad solder connection on the transistor. No whistles and plenty of output. I really took my time when I initially soldered the components. Just goes to show how important it really is. Thanks for the help.

 

[Causefarley]

What are the DC voltage readings at pin 8 of the opamps? And what is the voltage reading at pin 5 of IC3?

What specific JFET is being used? And what are the values of RB1 & RB2?

Also, how securely is the JFET seated in those sockets? To counter any issues with sloppy socket connections, I gently 'wrinkle" the ends of the legs.

View attachment 70649

Awesome! I have been just adding a little solder to the leads but like this idea better. No heat on the components.btw the jfet is a 4339 and it actually worked great with the stock bias values.

 

[Cybercow]

Awesome! I have been just adding a little solder to the leads but like this idea better. No heat on the components.btw the jfet is a 4339 and it actually worked great with the stock bias values.

A 2N4339 is one of the optimal JFETs to use. Good. It should have a Vgs(Off) value of -1.00V (±0.05V) to work best with the stock bias resistor values.

Note that the JFET compression will have less affect as the Gain is turned up. IF you notice that, then the Vgs(Off) value is good for the bias resistor values.

Glad you sorted it out.