Twenty-watt, simplified, customized 6g3 build "SBS"

[kwijabo]

nice build!

did you change anything with the grounding to try to reduce the hum you were talking about? do you know if it is the first triode or the second triode? they're both coming from the same B+ cap, so i wouldn't think this would change anything, but you could try disconnecting the controls from the 220k and then grounding that 220k. if that works i would give each cathodes connection on V1 its own path to ground. or you could also try connecting the pots' grounds directly to the cathode connection's turrets.

edit: i see in your layout off the cathode grounds you show it coming off the middle of the 4 of them. but in practice you put it on the far left lug. instead of dis-joining them, you could move that connection to the middle. again, doing this i think would really be reaching for something but its the only thing i coudl think of.

also, yeah a duburrer works wonders. i built my first amp without one. once i found out how nice it was on my second, i gutted the first one and redid a chassis. a smooth hole really helps things stay secure, too.

and lastly, i've been doing the tab hole for pots, too, and really like it.

[xtian]

When I discovered the effect a 1K neg feedback path had on the amp, making it tame for bedroom but still toneful, I had no more worries about the level of hum when the NFB was cranked to 56K and the amp is roaring loud.

With 1K NFB, the hum nearly disappears, on par with other good amps in the studio, so no worries. And seriously, the path to ground from the V1 cathodes is only a few centimeters long; didn't think moving it around would be of much help.

Thx for the comments!

[xtian]

Faceplate from http://www.labelengraving.com arrived. All finished, and ready for happy customer.

[rdjones]

Faceplate from http://www.labelengraving.com arrived. All finished, and ready for happy customer.

Nice job dude !
Cool finishing touches too, the serial number plate.

rd

[Structo]

Looks real nice and that cab is awesome.

Are the voltages a bit higher since you used SS rectifiers?

[xtian]

Thx, guys!

The plate voltage is 450, upper end for JJ 6v6. Sounds great.

New owner picked it up today. Happy camper. He owns three of my builds now!