Small portable, really portable practice amp
« Reply #20 on: November 11, 2005, 03:29:10 PM »
Quote from: "Ptownkid"
Ok, so i built two of these guys, and all I get out of them is distortion, or a lot of distortion, there's no cleanish tone at all.

Also, when you pluck a note, it hardly sustains at all and then quickly crackles off into nothingness in the blink of an ye, it's like it's got a gate.


leave out the 1k pot or 5k between pins 1 and 8.

for just raw clean power, try just a bare wire between 1 and 8.


Ptownkid

Small portable, really portable practice amp
« Reply #21 on: November 11, 2005, 04:32:19 PM »
that's the part I don't get, if you listen to the sound clip for the little Gem on runoffgroove, it's a hell of a lot cleaner.

I'd still like to understand what causes the gating.

PRR

Small portable, really portable practice amp
« Reply #22 on: November 12, 2005, 01:32:09 AM »
> all I get out of them is distortion, .... it hardly sustains at all and then quickly crackles off into nothingness...

Some stage is mis-biased. Without looking at the schematic, I would expect all R-C coupled stages to have a plate voltage very roughly half of the supply voltage. 0.3 or 0.8 might be OK, but 0.1 or 0.9 is dubious. Could be a wrong part, a bad part, a misconnection, or a sick tube. The transformer coupled output stage should show reasonable cathode bias (find the datasheet for the tube).

Small portable, really portable practice amp
« Reply #23 on: November 14, 2005, 10:04:44 AM »
ive built a few.

you should get some clean tones out of it with the "gain" turned all the way down....

i think prr is right...something must be wrong with your build.


 

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