Help with clandestine preamp

[chinaski]

Hello all!
Just built a clandestine preamp and the output when engaged is VERY low. I have it biased at half the voltage I found at R101.
Any suggestions are appreciated!

 

[chinaski]

Thank you; I’ll look at that on Monday.
Also, I just realized that my photo is really shoddy.
I’ll post a better one.

 

[chinaski]

My voltage readings so far:

At r101: 21.72
At the center test point: 12.12
On the ic:
Pins
1: 9.27
2: 4.49
3: 0
4: .138
5: .33
6: 4.3
7: 5.8
8: 9.27

I hope this might be enough info for someone to glean what I did wrong

 

[spi]

with jfets, the issue could be the transistor--where did you source it? lot of non-legit 2n5457s out there

 

[chinaski]

I got the transistor from amplified parts or pedal PCB; I don’t remember exactly.
In any case I got 2 and switched the first one out already.
Is there a way to tell if it’s bad testing it in circuit?

 

[DDad]

It is also helpful to see the underside of the board, to see if the flux and solder spatters have been removed. If the components are all correct and in correct orientation, a likely cause would be that the board has not been cleaned well enough.

 

[spi]

Is there a way to tell if it’s bad testing it in circuit?

Not sure if you can, maybe comparing to some good known voltages.

the way I've tested jfets in the past was using the technique described here:

A closer look at the Fetzer Valve

 

[chinaski]

I’ll try to post an underside pic tomorrow

 

[chinaski]

..and thanks again