53 Fender Tweed Pro

[butwhatif]

Any one have an opinion on a replacement OT for a 53 tweed Pro?
Also, what was the stock primary winding impedance of the originals-
6.6K, 4K ?

[klingo]

are you meaning 5E3 tweed deluxe?
8k in this case.
edit

[butwhatif]

1953 tweed Fender Pro-Amp, either 5C5, 5D5, or 5E5 is late '50s

[two tone]

6600 ohms I believe

[butwhatif]

Can anyone else weigh in on this? The options I've seen are 4K, 4.25K, and obviously 6600. Anyone know what the originals were? Anyone know what the original Fender part # was? thanks,

[rfgordon]

The 5C5 ran a pair of 6L6s in cathode bias with 6SC7 octal preamp tubes (later 12AX7), and a paraphase PI. The published Fender schematics label the OT as 1846.

Most of Fenders OTs for a pair of 6L6s would have been around 4K primary. That's a pretty happy spot for a pair of 6L6s, and it's what most replacements will be.

[Structo]

Yes that seems to be a common value of impedance for a pair of 6L6's.
(4K ohms)

[two tone]

4k with fixed bias p-p,6k6 with cathode bias p-p

[skeezbo]

I don't mean to hijack the thread, but why would cathode bias require the primary to be different? All the cathode bias mods seem to get by with the transformer that is on board; but if you are designing a cathode bias 6L6 amp should you go for the higher value?

Skeep

[rfgordon]

Cathode bias doesn't require a different value, but either value will work. They'll just differ in terms of tone and feel.

I use 4K pri iron in my cath bias 6L6 amps, which run a very tweedy 405 VDC on the plates. Very nice recipe, that. Add hempcones to taste....