shaka tube problems

[bagudan]

Hi. I´ve just finished buliding the shaka tube from paul marossys layout. Everything seems to be working, but i t doesn´t sound that good. When the bias trim pot is all the way up, the pedal has some sort of  hi-pitch noise....when the trim pot is turned down (a little), this problem dissapears, but the "drive" becomes very dull....  when turned further down.....sound dissapears.

I tried to match the voltage readings form paul marossys website.... succeeded with both V- and Bias, but then V+ said approx 7 volts ( Pauls said(11.8 volts)
Does this make any sense?

This is my first tube-build, so I don´t know what to look for?

[GibsonGM]

Hi,
Read the "Debugging" thread...it applies to a small tube project as well as to opamps etc.   There are a few things that could be wrong, but going thru the steps will help with your knowledge of how these things work!  You will have to post back your voltages in the circuit.

Could be a wrong value resistor or pot, a bad solder connection, solder 'bridges' between points that should not be connected....at last, you might find the tube is bad (although they are built like bricks, it can happen...).   The high pitched noise suggests oscillation, which in turn suggests (to me at least) that some output signal is getting back to the input (bad or wrong connection somewhere).

Go read that Debugging thread ;o)  And post back, you will get lots of help after that...

[bagudan]

Hi, and thanks for your post. I found the problem. I solderes in a status led in a stupid way....i´m not used to AC. The voltage readings  are now more like the ones on marossys page. the overdrive sounds much better as well. Still I get high pitched noise when trim pot is turned up...and it doesn´t seem to have much sustain.... maybe its a bad tube. I´m using a Sovtek 12ax7 ecc83 lps. I´ve followed the debugging thread, and triple checked components and connections. Everything seems to be as it should. I´ll try another tube.... any recommendations?