Ross compressor into a tubescreamer, and I didn't mean too! Help?

[erick4x4]

So I got my ross compressor working (sort of). Now it is really distorting, very much like clipping diodes do. I have checked for solder bridges around the diodes and can't find anything? All my part values appear correct (I measured the resistors prior to putting them in, not that I couldn't have made a mistake), and I have checked the cap values. I have checked the orientation of the diodes and electrolytics.  Any ideas? Could I have a bad 3080? I only have 1 so I can't compare it.

I am using 3904 trannys. Voltages look fine, though I will post them anyway. Ideas? It basically appears as if no compresion is happening at all. The sustain knob doesn't do anything. Its the same sound I would get out my orange squeezer if I adjusted the trim so that the compressor wasn't kicking in.

Thanks!

-Erick

Voltages:

IC:
Pin 1: 0v (na)
Pin 2: 4.74v
Pin 3: 4.73v
Pin 4: 0v
pin 5: 1.99v (this voltage was a little jumpy measuring)
pin 6: 2.65v
pin 7: 9.68v

Transistors (labels from tonepad layout)
Q1: c: 8.46, b:  1.77, e 1.23
Q2: c: 7.64, b: 2.64, e:2.06
Q3: c: 9.54, b: 0, e: 0
Q4: c:9.54, b:0, e:0
Q5: c: 9.68v, b: 9.54, e: 9.06

Lowered the 220pf to 150pf, but that shouldn't matter, just trying to get a touch more high end.

I know these style compressors can clip a little with loud guitars, but it does it from my tele to Les Paul so I don't think I am overdriving it. Plus it is not subtle it is as much distortion as a tubescreamer with the gain turned up. Like I mentioned, basically like no compression is happening whatsoever.

Ideas?

[bancika]

I had almost the same problem with mine but sustain pot increased distortion (fuzz)...it was wiring problem, so make sure you wired all componens properly and all trace cuts are cut, providing you use vero board.
Cheers

[erick4x4]

Well I guess thats usually the answer to these sort of problems. Though I am quite sure I wired it correctly. I used a tonepad PCB, and have really checked for solder bridges. Any other place to start? Am I right that this probably has something to do with either the diodes, or the fact that the sustain knob does nothing to increase compression (or any to begin with)?

I will start Audio Probing it. I just never know how to interpret this data. In a circuit like this where would the compression start happening?

[petemoore]

IC:
Pin 1: 0v (na)
Pin 2: 4.74v  Probably around 1/2v
Pin 3: 4.73v 
Pin 4: 0v  Gnd.
pin 5: 1.99v (this voltage was a little jumpy measuring)
pin 6: 2.65v >Not real sure about 3080 biasing, but 5 and 6 look low...
pin 7: 9.68v  >Battery is good!

Transistors (labels from tonepad layout)
Q1: c: 8.46, b:  1.77, e 1.23 >not sure if this is an emitter follower/
Q2: c: 7.64, b: 2.64, e:2.06  >or this one
Q3: c: 9.54, b: 0, e: 0  >With the base @ 0v, this one can't pass signal
Q4: c:9.54, b:0, e:0  >Same here
Q5: c: 9.68v, b: 9.54, e: 9.06  This one's base and emitter are real near V+ Rail
   Something is ~grounding the bases on Q's 3 and 4, test for Non-continuity to ground.
  Q5's emitter is way up there, perhaps it's not connected ?

[royzic]

i have the same problem with my rossn too

[Barcode80]

old thread, but i have the identical problem with distortion, and an unacceptable amount of hiss

[MartyMart]

old thread, but i have the identical problem with distortion, and an unacceptable amount of hiss

I had the wierd "Hiss" problem too and found that I had simply reversed one of the tantalum caps
- I think a 1uf somewhere !!!
Fixed it right away and the cap wasn't damaged either.
Have a close look at the schem/board for orientation.
Adjusting the trimmer to centre should remove the breakup BTW - or just use 2 x 1k resistors and
forget the trimmer.
MM