debugging valvecaster

[bonkdav]

Ive been curious about the valvecaster and i decided to get some tubes and build one.  ive been using the layout and schem from this thread http://www.diystompboxes.com/smfforum/index.php?topic=63479.0 i built it from the layout and it didnt work.  I then redid the tonestack and volume pot according to the schem with no go either.  both times i noticed that i would get a  hum when i touch then enclosure when turning the volume knob that was controlled by the volume knob. i tried multiple tubes and its still dead silent.  Ive gone over the circuit several times and i cant find anything thats wrong with it yet so that brings me here. the tube doesnt light up but it seems to get  warm and ditto for ther battery. here are some voltages i measured on the tube socket. its running with a green led with a 1.5k resistor for an indicator.  i didnt really do any mods besides using a 250k b pot for the tone because of lack of 100k a pots.

battery=8v
pin 1= 7.9v
pin 2= 7.7v
pin 3=about 0 or 228mv depending on which end of the 50k pots rotation your on
pin 4=2.6mv
pin 5=8v
pin 6=6.2mv
pin 7=0mv
pin 8=2mv
pin 9=7.6v

i think these are the right measurements but i did them in a hurry. i may remeasure them to see if its consistent.

thanks for any help.

davis

[Jered]

  First thing, this circuit is a battery eater. If your battery is only 8 V's its as good as done, need a new battery. But before you install the new one, you need to find your problem. Your battery shouldn't be getting warm. Is it room temp or noticeably warmer? A battery heating up is usually power and ground directly connected some where. Check for solder bridges etc.
  Jered

[andrew_k]

If you have a 9vDC or 12vDC adapter, use that instead of batteries.

I'm too much of a n00b to be much help, but I'll take voltage readings from each pin when I get home as a reference point for you if that's any help

[dxm1]

Your first job is to see why pin 9 has 7.6V on it - it should not be connected to anything...

[Renegadrian]

Yeah, why the hell did you decide to power via battery?! You said you followed both the vero layout I made and the Dano schem, but no battery there...Also, the vero version (the last one) has the tonecontrol wired correctly, Dano's also will work, only reversed.And yeah, pin 9is left unconnected...

[drewl]

pin 9 is a heater (filament) pin so it should either be 0v, 6v or 12v depending on how it's being used.
pin 2 should have no dc voltage on it.
I had a similiar problem where I was getting the plate voltage at the input pin2 nailing me with about 200v (tube amp) in which the problem was an intermittant cathode pin 3 ground.
So check for a bad/intermittant gain pot and that it's properly grounded.