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Hoffman Amps Forum image Author Topic: Advice for a power transformer  (Read 1132 times)

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Offline acheld

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Advice for a power transformer
« on: February 03, 2025, 02:00:27 pm »
My next build will be something like DaGeezer's Tweed Bluezmeister, Tubenit's version.

This amp features 2 12xx7's and 2 6L6GC tubes in self biased operation.  I've built only one self biased amp before, a BJ-IV version.

What would be a suitable estimate of B+ current ?   When I look at the data sheets for a 6L6GC, the plate current is listed at around 210mA in self bias mode.   Is this correct?  It seems very high to me -- I think I'm looking at the wrong spec . . .

Offline SEL49

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Re: Advice for a power transformer
« Reply #1 on: February 03, 2025, 02:15:04 pm »
When I look at the data sheets for a 6L6GC, the plate current is listed at around 210mA in self bias mode.   Is this correct?  It seems very high to me -- I think I'm looking at the wrong spec . . .
Yeah, 210mA sounds wrong. You should be able to use a PT that's rated for 150mA or 175mA.

Offline AlNewman

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Re: Advice for a power transformer
« Reply #2 on: February 03, 2025, 03:48:50 pm »
Probably depends on what voltage you want.
30W @ 300v is 100mA/tube.
30W @ 450v is 66mA/tube

Offline AlNewman

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Re: Advice for a power transformer
« Reply #3 on: February 03, 2025, 03:53:09 pm »
Plus screens, preamp, etc...

Offline mresistor

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Re: Advice for a power transformer
« Reply #4 on: February 03, 2025, 04:31:05 pm »
The original Tweed Bluesmeister uses 5881s (well I see 5881s on the layout and 6L6 in the schematic) but could use 5881s.   One would think that any PT for a Fender amp or equivalent using 6L6s would work well. 


https://el34world.com/Forum/index.php?topic=9498.0
« Last Edit: February 03, 2025, 04:47:33 pm by mresistor »

 


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