dynacomp clone from tonepad - amidoinitrite?

[egasimus]

okay, so I built a dynacomp + ross resistors by the tonepad schematic... it works - there seems to be compression, but there is also a certain lack of brightness. now, I'm only plugging into my PC's sound card, which sounds like crap, but the sound should be brighter after being buffered by the circuit, right?

I also read some voltages for the Ross compressor here, which don't correspond with what I've got, so perhaps I might have a problem. Anyone care to have a look?

MXR/Ross hybrid from Tonepad
02.09.11 by egasimus

Voltage readings:

V+ to GND: 9.88V (battery)
Current drawn: 0.7mA

CA3080
1: 0.06
2: 4.22
3: 4.23
4: 0
5: from ~6V to ~9V when turning Sustain pot.
6: 2.69
7: 9.88
8: 0.03

Hmm, those look dodgy. Gonna go grab a bite to eat, then reflow the traces to pins 4 and 7. I'll post measurements of the transistors if you think I need to. Given what the mess I've apparently made, I think I'll do.

[egasimus]

Had dinner, and, guess what, I had measured them voltages wrong. Corrected now

[oskar]

Voltage readings:

V+ to GND:[/b] 9.88V (battery)
Current drawn: 0.7mA

CA3080
1: 0.06
2: 4.22
3: 4.23
4: 0
5: from ~6V to ~9V when turning Sustain pot.
6: 2.69
7: 9.88
8: 0.03

From the link you provided:

IC1 (CA3080E)
Pin 1 = N/U*
   Pin 2 = 4.92V
   Pin 3 = 4.91V
   Pin 4 = 0V
   Pin 5 = 0.633V
   Pin 6 = 2.76V
   Pin 7 = 9.5V
   Pin 8 = N/U*
*N/U = Not Used (not connected to anything)

Compare the voltages on pin 5.
On the inside of the 3080 pin 5 has one diode connected to ground. It should read more like the 0.633V
from Fuzz Central. Also your pin 4, ground, reads 0V so the problem doesn't seem to be a badly grounded chip
but perhaps a faulty one.

[lopsided]

5: from ~6V to ~9V when turning Sustain pot.

Yes, pin 5 is supposed to be around 0,6 V. Not sure if your high readings signify a mistake in the circuit or a faulty chip.
R.G. wrote elsewhere (http://www.diystompboxes.com/smfforum/index.php?topic=82447.0):

Pin 5 is where the current telling the chip how much to amplify comes in. This pin is **always** at 0.4V to 0.7V on a 3080 if it's working

[egasimus]

I think the voltage at pin 5 is the same without the chip, so it's not a faulty device. Which is odd, cuz it still seems to work great - there is also a noticeable, pleasant, and variable by the "sustain" pot amount of compression. I'll have to try it in my external sound card (with guitar input) to actually hear if something's wrong, though. I ain't got no guitar amp...