Tube Screamer - very low volume on effect

[the monroe transfer]

Hi all.  Here's a quick problem with a Tube Screamer- when the effect is switched on, the volume is very, very low.  The pots seem to be controlling the effect parameters fine but, as I say, at very low volume.

I'm using this layout here...
http://www.tonepad.com/getFile.asp?id=81

No modifications, as such- I'm using the TS808 components, and 3 diodes for asymmetrical clipping.  Is there something obvious I should be looking for, or shall I get to measuring all the voltages?

[petemoore]

Is there something obvious I should be looking for, or shall I get to measuring all the voltages?
  Only as obvious as something you could sense..
  I would skip right to the voltages after a cursory observation period, looking for ob faults.

[the monroe transfer]

Whoops.  I'm debugging a board I made sometime last year, and forgot I used polarised electrolytic capacitors, instead of the non-polarised ones.  Could that be making a difference?  The circuit doesn't actually need bipolar capacitors, does it...?

EDIT:  Yes.  Yes, of course it does.  What a stupid thing to say, and do.  Now I just need to find some non-polarised capacitors...

[the monroe transfer]

Well, I've found some non-polarised electrolytic capacitors, and replaced them.  Unfortunately, that hasn't changed the lack of effect, so here are some voltages in case someone can help me.  The layout is here (http://www.tonepad.com/getFile.asp?id=81)

(battery voltage 8.66V)

JRC 4558D (from this datasheet- http://focus.ti.com/lit/ds/symlink/rc4558.pdf)
1- 4.31V
2- 4.50V
3- 4.25V
4- 0.00V
5- 8.71V
6- 4.32V
7- 4.32V
8- 4.28V

Transistors (2N3904, pins labelled from here- http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS013058.PDF)
Q1- C- 8.69V
      B- 4.28V
      E- 3.68V
Q2- C- 8.68V
      B- 4.28V
      E- 3.68V

Do I need to go on, or are my errors obvious already...?

[the monroe transfer]

Bump, with some embarrassment, but I have a decent chunk of today in which I could fix it...

[oskar]

1- 4.31V
2- 4.50V
3- 4.25V
4- 0.00V
5- 8.71V
6- 4.32V
7- 4.32V
8- 4.28V

pin 8 should be more like pin 5 from above and vice versa. Are you shure you didn't write them down in wrong order?

[the monroe transfer]

Yes.  That's exactly what I've done.   

Pins 5-8 are in reverse order.  Whoopsie.  Does that mean that the IC and transistor voltages are ok?  Should I move on to...well, everything else?

[oskar]

Go audioprobe on it...
You should find the problem really fast.
My guess is the inputwire...

[oskar]

Mixing up Ra and Rb would off course lower the volume considerably...     

[GibsonGM]

+1, hit it with the probe, make it talk to you!!  It'll tell you where it's hurting...

[the monroe transfer]

Time to share more embarrassment.

As I mentioned, I started building this last year, got sidetracked and stopped.  I'm now debugging it.

And I can't imagine what I was doing.  I'd put seemingly-random value resistors in some places, caps were in the wrong way round...ugh.  Just all-round idiocy.  Double and triple-checked all the components, and everything seems to be fine now. 

The lesson I've learnt here is that the idiot I am now is very different to the idiot I was last year. 

Thanks for the help, all. 

n