Valvecaster problem

[macombaland]

I have gone over this thing a thousand times and cannot find a problem..  There is signal coming from the output but it is hardly anything even when the volume and gain are maxed out

I built the point to point version of this http://www.beavisaudio.com/Projects/ValveCaster/MatsuminValveCasterWiring.gif
http://www.beavisaudio.com/Projects/ValveCaster/MatsuminValveCaster.gif

I substituted the 470k resistor for a 65 and 390k in series.
Voltage at the power supply is 10.36V
here are my voltages on the pins
1- 9.2V
2- .09V
3- .22V
4- 0V
5- 10.36V
6- 9.93V
7- .14V
8- 0V
9- 5.28V

[frequencycentral]

Pin 1: 3.02v
Pin 2: -0.518v
Pin 3: 0.00v
Pin 4: 0.00v
Pin 5: 11.97v
Pin 6: 8.21v
Pin 7: -1.285v
Pin 8: 0.00v
Pin 9: 5.91v

DC power in is reading 11.99v.

Gain at maximum.

My gain pot is 100K not 50K.

Looks like your problem is at Pin 1. Good luck!

[macombaland]

sorry it has been a while since i have had a chance to work on this... I hope its ok to use this thread after so long.  I have been probing around and I have very distroted signal coming out of pin 1, 3 and 7.  Pin 2 has the clean singnal.  Is this normal???

[frequencycentral]

sorry it has been a while since i have had a chance to work on this... I hope its ok to use this thread after so long.  I have been probing around and I have very distroted signal coming out of pin 1, 3 and 7.  Pin 2 has the clean singnal.  Is this normal???

Pin 2 would be clean, as that's the input.

The signal at pins 1 and 3 should be clean, as the first stage just boosts the signal. The Valvecaster distorts because the (boosted) output of the first stage overdrives the second stage. With the gain control turned to minimum the output at pin 3 should be clean, quieter than the output at pin 1, and 180 degrees out of phase with it.

The signal at pin 7 should be pretty much the same as the signal at pin 1

Are you sure your wiring is correct? And are your voltages the same as you posted above?

[macombaland]

Voltages are about the same as above.  I have put this thing together using the vero layout, point to point, and on my breadboard with the above results each time.  I also have an extra tube which I swapped but still had the same results.  Thanks for the response by the way.

[Swoon]

Sorry to bump this old topic, but I seem to have about the same voltages as the thread starter.
I also have followed the same layout. I've double checked everything, measured for shorts... etc... I do not seem to be able to get the voltage on pin 1 to drop.

Is there anything in particular I could check? Running a 12V filtered power supply. Using 12AU7 tubes...

Thanks!

[frequencycentral]

You should really publish all your voltages.

But check the value of R2 - it should be 220K. Check it three times!

[Swoon]

Ok thanks,

I will post the voltages when the effect is assembled again. It's getting a paint job now

Thanks!

[danamoose]

Haven't seen any solution on this and I am experiencing the same issue using Renegadrians layout which is about the same as this.
Any resolution?

[iccaros]

are you using a 12au7?

[danamoose]

Yes using a 12au7. Built using Renegades "no tone" layout. I took it back apart this afternoon, verified component values and locations in the circuit. I dont spot any errors. I am running it on 9 volts. Not hearing any hum or noise, but the output is very low...a touch lower than the bypass volume.  I do hear overdrive but it is crunchier than I expected. Any thoughts? Thanks!

[artifus]

danamoose, danamoose - can you do the fandango?



sorry, couldn't resist. built the stock valvecaster some time ago with a 6072 which i think is a 12au7 equivalent with no probs but have only ever run it at 12v. i like it. not much help i know, just wanted to get the fandango in there. good luck.

just had a thought - you say 9v but what current? it's a pretty hungry device. i run it from a 12v 1200ma regulated psu. hth

[PRR]

> Any thoughts?

Not without voltages.

You need a strong 9V across pins 4-5 (should be 11V-13V really).

Pins 2 and 7 should be near ground. A part-volt is normal (and one reason low-volt tubes are so tricky).

Pins 1 and 6 should be above 3V but well below the suppy voltage.

See Rick's voltages (2nd message). Wide variation is expected (his pin 1 and 6 voltages may be extremes) but anything way-off is your Clue.

[ozzu2000]

Had the same problem as described above (all connections double checked, very low output) so I'll post here my "fix".
I was using a battery pack that read 10v, but as soon as I plugged the pedal to it, the voltage dropped to 7v.

The solution was to use a supply that would give me a stable 9 volt, when loaded. In my case, fresh batteries!
All is good now!