Please help with EVH 5150

[whomeno]

ok built the EVH 5150. as soon as I switch it on I get a squeal. When I probe it at input it  is fine to IC1 pin3. At IC1 pin 1 the noise starts.. I checked the board for shorts nothing found. I checked the position of all parts, they all look too be in the right place.
Voltages 9.04 input
IC1 TL062
1- 4.35  2- 4.33  3-4.29   4-0    5-3.32   6-4.32   7-4.31   8- 8.80
IC2 TL062
1-4.33   2-4.33   3-4.27   4-0   5-4.29   6-4.33   7-4.38   8-8.80
IC3 TL062
1-4.35   2-4.33   3-4.33   4-0   5-4.23   6-4.33   7-4.33   8-8.80
IC4 TL061
1-.04   2-4.33   3-3.37   4-0   5-.048   6-4.33   7-8.80   8-0
Q1 2SK117
D-8.80   G-3.94   S-4.74
Q2  2SK117
D-8.80   G-3.97   S-4.78
Q3 BC557B
C-3.95   B-5.07   E-4.33
Here is the build, pics and schematic

[antonis]

Place a 4.7nF across 8k2 feedback resistor..

[whomeno]

ok will try it and let you know

[whomeno]

I'm sorry posted the wrong layout. I put the right one up.
I added a 4.7nf to the 7.5K resistor. did not help.

[GibsonGM]

Can you elaborate on the squeal?  Does it change when you turn pots up and down? Can you hear ANY guitar at the output through the squeal? 

Are you powering it from a battery or power supply wall wart?

Are the resistor in the feedback loop of IC1 all the correct value?

[whomeno]

Yes it changes when i turn the pots up and down.
yes the guitar signal is coming through
I tried both power supply and battery still have the squeal.
yes feed back loop is the correct values

[whomeno]

I found it. It was the 5.6nf to the right of IC2. it was off 1 hole. working fine now thanks for the help

[whomeno]

the squeal is gone but when I engage the pedal it is lower volume then the bypass. what would cause that?

[whomeno]

I'm probing it. good signal coming out of IC1 pin 7 going to the 220nf loose a lot of signal going through the 220nf heading to gain 3

[whomeno]

ok here is what I got.
I have to max out the volume and gain to get the same volume as the bypass volume.
Is there a way to up the volume more?

[ElectricDruid]

ok here is what I got.
I have to max out the volume and gain to get the same volume as the bypass volume.
Is there a way to up the volume more?

That's not the solution. You need to fix the new problem. Tell us some more about this 220n.

[whomeno]

there was a bad solder joint which is fixed I got good signal completely through now. I only have the volume drop now

[ElectricDruid]

there was a bad solder joint which is fixed I got good signal completely through now. I only have the volume drop now

If you've still got the volume drop, you haven't got a good signal *all* the way through. Where does it go quiet now?

[whomeno]

going through the 360K at Q2

[whomeno]

if i bypass the 360K to switch 2 it works great

[whomeno]

I took the 360K out and jumped the cut there. now it is working perfect.

[idy]

There is no 360k in the schematic. I see it on the layout. They don't agree, do they? Good work.

[duck_arse]

There is no 360k in the schematic. I see it on the layout. They don't agree, do they? Good work.

there is also a 6k2 shown on the layout doesn't match the circuit dia. and if I might ask, what value cap have you fitted across that resistor, at 17 E&F? it doesn't match the other nearby should-be-same-value, which always piques my interest.

also a 7k5 around IC1 doesn't match - I stopped looking after that.

[whomeno]

There is no 360k in the schematic. I see it on the layout. They don't agree, do they? Good work.

there is also a 6k2 shown on the layout doesn't match the circuit dia. and if I might ask, what value cap have you fitted across that resistor, at 17 E&F? it doesn't match the other nearby should-be-same-value, which always piques my interest.

also a 7k5 around IC1 doesn't match - I stopped looking after that.

at 17 E&F..... 5.6nf