tube reamer 2 debuging

[blanik]

hi, i just finished a Tube Reamer 2 (vero version by RM Rivers)
the signal is going through but doesn't distort... volume works fine, sound is very clean, not even a slight buzz and the drive pot doesn't do anything... (checked for shorts but even if pot was shorted on the "clean" position i would probably still getting some sort of fizz in the sound...)

something like that ever happened to anyone? (specially in any overbuilt TS variant  )

R.

[petemoore]

  yes, then I did 'classic' debugging on it.
  Testing all ground points marked.
  Voltage measurements.
  Thumbuzz...pretty sure I got it at this point.
  but audio probe is a popular item. 
  and other items more than suggested in debugging thread like measured battery voltage.

[blanik]

yeah, i did all that (except audio probe, don't have one) i was expecting something like "oh yes, happened to me, check your C5 caps, it's probably shorted" 

the fact that's different about this bug it's that the sound is very clean while being loud like the pedal should be... sounds like a clean booster! 

[blanik]

 
went all over it againg with continuity test and resistor tests.. no shorting tracks, switch ICs, all resistors read good values according to RM Rivers vero...

the pedal sounds great... as a clean booster! 
i took some readings (below)

the schematic is so simple, i can't beleive no one can guess where to look for (i don't have a cap tester on my DMM  )..
absolutely no clipping occurs...

some readings...

IC:4558
1- 4.82V
2- 4.20V
3- 3.84V
4- 0
5- 4.81V
6- 4.81V
7- 4.81V
8- 8.33V

all other voltages at different resist. or caps leads read around 4.2V to 4.8V (except on grounded leads)

batterie at 8.33V

vero layout i used

[MartyMart]

There's an error on the vero, where R2 meets C1, just right of them make a trace "cut"
Third row up directly below another trace "cut"
otherwise R2, the 2k7 goes straight to ground via pin 4 of the opamp.
It needs to pass through C1 .22uf first

Marty

[blanik]

Thanks Marty!! now it's clipping!!!   

so much actually that it's oscillating (high pitched squeal) when i turn drive or volume past 50% ! 

this one is a tough one...

R.