Fender Tweed Twin Reissue JB Edition

[a j shaner]

At times I have considered using a 5AU4 but have not found the proper power transformer for the HT or sufficient filament current. I would think you could have one built along the lines of 300-0-300 @ 450mA/6.3VCT @ 6A/5V @ 5A. This would be sufficient to run 4- 5881 tubes and up to 6- 12A_7 tubes. For what its worth the 5AU4 draws 3.75A of filament current.

[strat100]

Got a spare Hammond 290Fex (Twin Reverb power tranny) and was thinking along the lines of using it for a tweed twin but with diode rectification, would there likely to be any pitfalls that i should be aware off?

[Guy77]

Hi strat100 . I have used the 290FEX in several 100 watt JM builds and its a great transformer! One of them is gigged weekly and has had no problems.
With 4x JJ 6L6GC tubes and 5 preamp tubes I get the B+ to stay at around 420V . My wall voltage is 117v . I run the tubes at about 34ma each.
I really like the results I get with this transformer and its nice and beefy at 11.5 lbs.
I am not sure if this B+ is ok for you but reliability wise its a fine transformer.

Cheers

Guy

[strat100]

Thanks for info Guy77 if needs be i could knock the B+ down to around 400v with the mosfet b+ reducer. Who needs sag anyway

[Roe]

https://www.youtube.com/watch?v=3z2gU8KOAE4

Tweed Twin, Joe Bonamassa limited edition
First Tweed Twins to come out of Fullerton in what, 50 years?
Celestion JB-85 speakers (Ipswich made Classic Lead 80)
Tung Sol Reissue 6L6s
12AX7s in all three positions
Mercury Mag transformers

**Humble request: please don't slag Joe, if you hate'em and/or see this as a money grab. Let's just revel in the fact that Fender reissued this amp.**


Tweed Twin JB.jpg

whats the diode between the screens and heater on v4 and v7?

[Colossal]

whats the diode between the screens and heater on v4 and v7?

There is an R3000 diode to ground on pins 3 of V4 and V7 for flyback protection. Is this what you are referring to?

[Roe]

whats the diode between the screens and heater on v4 and v7?

There is an R3000 diode to ground on pins 3 of V4 and V7 for flyback protection. Is this what you are referring to?

yes!