SF deluxe reverb power tranny replacement

[Hiho]

Hello all,

I am new to this forum, first post! I live in Melbourne, Australia and have been building guitar effects pedals and other music electronics for many years. I have recently aquired a ~1975 deluxe reverb from the states. As my power is supplied at 240v I'm running it off a step down transformer. I would like to replace the power transformer with one tapped for 240v use. This leads me to the following questions:

What brand of transformer should i use and who supplies them?
Are replacement deluxe reverb power transformers wired for the black face rectifier voltage or for the silver face rectifier voltage?
Should i take this opportunity to blackface my silverface?

Thanks and I look forward to hearing from you!

Cheers,
Matt

[MWJB]

1) Mojotone & TAD supply them, with export taps, will run BF spec with a GZ34 & 6V6.

2) There's not a lot of difference in the circuits between BF & SF Deluxes (Deluxes, Princetons, Champs & even the Vibroluxes didn't change much) - 1200pf caps from pin 5 of the 6V6s to ground, one more from the reverb return to ground, 330K grid reisistors at the PI instead of 1Meg. Clip off the 1200pf caps, if you have resulting stability problems put them back.

[Hiho]

Thanks for your reply!

Am I correct that the main difference between a good sounding BF and a good sounding SF is that the SF does clean well and breaks up at a higher volume than the BF? Would I be correct also to say that this difference in 'headroom' is due to the higher voltage supplied to the valves by the SF PT/rectifier valve combo?

So other than the oscilator caps and some very minor circuit/component alterations, the main difference between the two amps is in the power supply and the colour of the face panel?

As I would prefer an amp that gets crunchy at a lower volume, and that the amp was badly damaged en-route to Australia, I think that I will blackface it.

So the tranny options are hammond, heyboer, mojo, TAD? I can source the hammond 290bex here in australia, all others would have to come from the States. Any opinions on these transformers?

[MWJB]

"Am I correct that the main difference between a good sounding BF and a good sounding SF is that the SF does clean well and breaks up at a higher volume than the BF? Would I be correct also to say that this difference in 'headroom' is due to the higher voltage supplied to the valves by the SF PT/rectifier valve combo?" No, both amps run their tubes at similar voltages at the end of the day, SF models may run the PI tube & preamp at higher voltage due to a smaller power supply dropping resistor. Differences & preferences in tone would come down to the specific amp in question rather than the colour of the faceplate.

Hyboer make transformers that are available from Mojo & TAD. The Hammond is a drop in replacement made to the same spec.

[Hiho]

I have been told by a local amp tech that the heyboer and hammond PT's run high plate voltages (450-460V). What experiences have you guys had with building amps with these transformers?

The amp tech claims that a local winder makes transformers that are on spec for the AB763 circuit with GZ34 for around the same price as the Hammonds/Heyboers. I am reluctant to go with an unknown product and would like to make as informed decision as possible with regards to this modification.

Cheers,

Matt

[Bruce / Mission Amps]

I have been told by a local amp tech that the heyboer and hammond PT's run high plate voltages (450-460V). What experiences have you guys had with building amps with these transformers?

The amp tech claims that a local winder makes transformers that are on spec for the AB763 circuit with GZ34 for around the same price as the Hammonds/Heyboers. I am reluctant to go with an unknown product and would like to make as informed decision as possible with regards to this modification.

Cheers,

Matt

I think the MOJO 761EX, when used with a correct 5U4GB rectifier, will give you want you need.
You mid 70s Deluxe Reverb did not come with a GZ34 anyhow.