Need Help: Compressor Build Issue

[kfowler8]

Guys,

I just finished building a DIY Ross style compressor from General Guitar Gadgets. I've got an issue where it's not working. I get no sound. True bypass switch works when not engaged. As soon as I press the stomp switch, the LED light turns on but I get no sound.

Below is the information

1.What does it do, not do, and sound like? It does nothing. No sound
2.Name of the circuit = Ross Compressor
3.Source of the circuit (URL of schematic or project) = General Guitar Gadgets (http://www.generalguitargadgets.com/effects-projects/compression/ross-compressor/)
4.Any modifications to the circuit? No
5.Any parts substitutions? Stock other than I use non-polarized Electrolytic caps from Mammoth (https://www.mammothelectronics.com/collections/electrolytic-capacitors/products/non-polarized-electrolytic-capacitors-audio-grade?variant=25348160775) for all of the Electrolytic caps. I also originally use 2 1K resistors and then replaced these two with a 2K trim pot. The board can use either option.
6.Positive ground to negative ground conversion? No
7.What is the out of circuit battery voltage? 9.35 (New battery
Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead = 9.27
Voltage at the circuit board end of the black battery lead = Zero (Assuming I did that correctly)

Transistor a IC Readings (Parentheses are referece readings from GGG)

Q1
C: 7.35 (7.5)
B: 2.45 (2.4)
E: 2.046 (2.0)

Q2
C: 9.27 (9.3)
B: 0 (0.05)
E: 0 (0)

Q3
C: 9.28 (9.3)
B: 0 (0.05)
E: 0 (0)

Q4
C: 9.41 (9.3)
B: 9.27 (8.9)
E: 0 (8.6)

Q5
C: 9.39 (7.0)
B: 3.00 (3.1)
E: 0 (2.6)

IC Pin
1 0 (0)
2 4.86 (4.4)
3 4.86 (4.4)
4 0 (0)
5 0 (0.7)
6 2.993 (3.4)
7 9.37 (9.3)
8 0 (0)

From these readings, obviously something's off.

Thanks so much for your help

[PRR]

> red battery lead = 9.27
> Q4 C: 9.41

How can Q1 be showing a voltage higher than the battery?

> Q4
> B: 9.27 (8.9)
> E: 0 (8.6)

> Q5
> B: 3.00 (3.1)
> E: 0 (2.6)

Difference B to E must be a part-Volt (rarely less; your Q2 Q3 readings are correct for no signal).

I would suspect wrong pinout or defective transistors except Q1 is sitting pretty.

When Q4 works right, '3080 pin 5 should come up to a few-tenths Volt and we will find out if you got a fake '3080.

[kfowler8]

> red battery lead = 9.27
> Q4 C: 9.41

How can Q1 be showing a voltage higher than the battery?

> Q4
> B: 9.27 (8.9)
> E: 0 (8.6)

> Q5
> B: 3.00 (3.1)
> E: 0 (2.6)

Difference B to E must be a part-Volt (rarely less; your Q2 Q3 readings are correct for no signal).

I would suspect wrong pinout or defective transistors except Q1 is sitting pretty.

When Q4 works right, '3080 pin 5 should come up to a few-tenths Volt and we will find out if you got a fake '3080.

Thanks for the help!

"How can Q1 be showing a voltage higher than the battery?" I assume you mean Q4 here? I re-checked my readings. Maybe I was tired last night but now I'm getting on Q4 C: 9.29 B:9.15 E: 0. That seems more reasonable.

So what would you try next? Should I swap Q4 for another transistor?

Thanks,

[kfowler8]

BTT

[Kipper4]

"That seems more reasonable."

Not when you compère your voltages to the ggg ones you posted.
His q4 E is at 8v yours is at ground.
Also q5 E???

[kfowler8]

"That seems more reasonable."

Not when you compère your voltages to the ggg ones you posted.
His q4 E is at 8v yours is at ground.
Also q5 E???

By "reasonable" I was referring to the voltage at transistor was not greater than the battery clip reading. Yes, there's still an issue with E on Q4 and Q5. That's what I'm trying to troubleshoot.

[kfowler8]

So as best I can tell, it looks like Q4 and Q5 were bad. I ended up replacing both and now it seems to work well. Now I've got to find a housing that fits.

Thanks again for the help.