6V6's in Tweed Super

RobBozic · 08-29-2009, 08:23 AM

I've just tried some JJ6V6's in a tweed super clone. My plate voltage is 435V with a 5R4GYA rectifier, I've got 1K 2W screen resistors.

The JJ6V6 data sheet says the screens can handle 450V & the plates can handle 500V, but I want to be on the safe side.

Should I increase the value of these resistors to drop the screen voltage down more?

Thanks
Rob

tubeswell · 08-30-2009, 02:56 AM

What is your plate dissipation? IMHO JJ6V6s in Class AB1 can handle those voltages if they are biased so that the dissipation is around 70-85% of 14W at idle - preferably on the lower side. (What do they look like when you fire them up?)

RobBozic · 08-30-2009, 09:51 AM

I've got them at 70%. Do you think I should bias them hotter so as to drop the voltage?

Rob

tubeswell · 08-31-2009, 09:24 PM

If that is what they are , they are running within spec. What do they sound like?

If you want lower volatges, why not try a 5y3G or zener down the B+?

08-29-2009, 08:23 AM	#1
RobBozic Member Join Date: Nov 2006 Location: Sydney, Australia Posts: 22	6V6's in Tweed Super I've just tried some JJ6V6's in a tweed super clone. My plate voltage is 435V with a 5R4GYA rectifier, I've got 1K 2W screen resistors. The JJ6V6 data sheet says the screens can handle 450V & the plates can handle 500V, but I want to be on the safe side. Should I increase the value of these resistors to drop the screen voltage down more? Thanks Rob

08-30-2009, 02:56 AM	#2
tubeswell Supporting Member Join Date: Feb 2007 Location: Wellington NZ Posts: 2,630	What is your plate dissipation? IMHO JJ6V6s in Class AB1 can handle those voltages if they are biased so that the dissipation is around 70-85% of 14W at idle - preferably on the lower side. (What do they look like when you fire them up?) __________________ Building a better world (one tube amp at a time) Last edited by tubeswell; 08-30-2009 at 03:13 AM.

08-31-2009, 09:24 PM	#4
tubeswell Supporting Member Join Date: Feb 2007 Location: Wellington NZ Posts: 2,630	If that is what they are , they are running within spec. What do they sound like? If you want lower volatges, why not try a 5y3G or zener down the B+? __________________ Building a better world (one tube amp at a time)

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08-30-2009, 09:51 AM	#3
RobBozic Member Join Date: Nov 2006 Location: Sydney, Australia Posts: 22	I've got them at 70%. Do you think I should bias them hotter so as to drop the voltage? Rob

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