5F6A Tweed Bassman Kit

MWJB · 03-11-2009, 10:06 AM

"My main filter caps are two 100mfd in series, so that's 50mfd vs the standard 40 mfd. Maybe it makes the bass a little tighter, maybe no one can hear the difference...." I have had customers comment, unpromted, on the difference between the parallel 500v caps and the series wired caps. I can hear it, so did they. Yes, the series wiring makes for a tighter sound.

jibe · 03-11-2009, 11:50 AM

Chinease 6L6GC is what's supplied with the kit, that's what makes me wonder if I have to lower B+ in order to switch to 5881. Thinking of getting the Tung-sol 5881.

//Jibe

MWJB · 03-11-2009, 11:53 AM

5881 will happily take your 470vdc, no need to lower B+.

Diablo · 03-11-2009, 01:25 PM

The use of 2, 4, or 8 ohms doesn't change the power output. But, is only used to match the speaker load through the transformer turns ratio to the power tubes. As has already been posted, the 5881 tubes can handle 460V without a problem, but don't bias them up as hot as 6L6GC tubes, since they can only handle 23 Watts max. I suggest around 35 mA per tube for idle bias.

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03-11-2009, 10:06 AM	#36
MWJB Old Timer Join Date: Jun 2006 Posts: 1,926	"My main filter caps are two 100mfd in series, so that's 50mfd vs the standard 40 mfd. Maybe it makes the bass a little tighter, maybe no one can hear the difference...." I have had customers comment, unpromted, on the difference between the parallel 500v caps and the series wired caps. I can hear it, so did they. Yes, the series wiring makes for a tighter sound.

03-11-2009, 11:50 AM	#37
jibe Member Join Date: Mar 2009 Posts: 40	Chinease 6L6GC is what's supplied with the kit, that's what makes me wonder if I have to lower B+ in order to switch to 5881. Thinking of getting the Tung-sol 5881. //Jibe

03-11-2009, 11:53 AM	#38
MWJB Old Timer Join Date: Jun 2006 Posts: 1,926	5881 will happily take your 470vdc, no need to lower B+.

03-11-2009, 01:25 PM	#39
Diablo Senior Member Join Date: Dec 2007 Posts: 505	The use of 2, 4, or 8 ohms doesn't change the power output. But, is only used to match the speaker load through the transformer turns ratio to the power tubes. As has already been posted, the 5881 tubes can handle 460V without a problem, but don't bias them up as hot as 6L6GC tubes, since they can only handle 23 Watts max. I suggest around 35 mA per tube for idle bias.

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