Rangemaster DC noise/ High gain transistor at fault??

[tonemonster]

This is a renewed plea for help with my almost very cool sounding Rangemaster clone. I built it using a terminal strip from the plans at RG Keen's site. It does work, it's wired correctly with the only questionable connection being the black battery wire to lug 5. The input and output caps are in place, and connected properly, the pots on the guitar are quiet. The instructions indicate that there will be SOME DC on the pot. I have about 1.5 volts (-1.5?).  ( I'm using an OC44 that is biased correctly but with with a gain of 190. The build instructions indicate that a gain above 150 is not useful for this project. Sadly I caught this AFTER it was built. Could excessive gain from the transistor be the culprit?)

[jaytee]

Have you tested the transistor for leakage?

[petemoore]

  Transistors Pinout.
  and type...pNp or NpN.
  Circuit type: PNP for Pos Gnd / NPN for Neg Gnd. ?
  Voltages, see / follow instructions in "Debugging' thread.

[tonemonster]

I bought the transistor from a well known supplier. It had been tested. regarding the circuit, it's a PNP.

[jaytee]

You may still want to test it yourself. Try disconnecting the base in the circuit and measure the voltage across the 3k9 resistor or the 10k pot. That will give you an idea of the leakage. If it is ok for leakage my feeling about it is you will need another transistor. Maybe who you bought it off will exchange it.

[MetalGod]

are you sure the Hfe measures 190 - that seems very high for an OC44 (mine all test around 80'ish)

[tcobretti]

I don't understand the problem.  Is it the voltage you are concerned about or does it make some weird noise?

[tonemonster]

Even when I'm not playing, It sounds like bacon frying in a pan. The provider of the Transistor said that it seems to be/ have gone bad, and is sending a replacement. It;s a cool effect, so I hope I get it working right.

[R.G.]

Even when I'm not playing, It sounds like bacon frying in a pan.

That's a classical description of excess noise caused by transistor damage.

Did you heatsink the leads when you soldered it in? Heat damage is one of the things that can cause this.

I wouldn't sweat the high gain nearly as much as the excess noise. I really think that you're seeing the transistor's failure as extra gain.

[tonemonster]

Thanks to all for your input. This has been driving me nuts! I followed the build instructions to the letter, and I did heatsink the transistor leads.   NOW I know what a bad transistor sounds lik ;De.