Suitable transformer for 3 12ax7 high gain guitar preamp build.

[Captain chunkulus]

Hey, I'm trying to find a power transformer that will do high voltage for a three tube high gain preamp that also has a secondary tap for the heaters.  I know I can do voltage doubling as an option as well. Trying to find something that could fit in a 1 rack space chassis. Any of you guys know of anything that might work? Thanks for any help.

[shooter]

quick search since your parameters are pretty vague;

 https://www.edcorusa.com/xpwr011
800vdc, plenty of amps n TWO filament windings 6.3 and 5

might not fit in you're box 

[kagliostro]

Toroidal transformer 230V -> 270V, 14V

Primary 230V, secondary 270V @0,08A and 14V @2A.

Diameter: 78mm
Height: 37mm

https://www.musikding.de/Toroidal-transformer-230V-270V-14V

or

Toroidal 47 VA

Pri: 0-220-230-240 V
Sec 1:  250 V / 0,1 A, 
Sec 2: 6,3 V / 1,5 A
Sec 3: 12,6 V / 1 A
Size: d = 80 mm, h = 35 mm

https://www.tube-town.net/ttstore/Transformer/Power-Transformer/Toroidal/Toroidal-47VA::5391.html

Franco

[2deaf]

I don't know what country you are in, but if you can get Signal Transformer products and you are willing to use two transformers, LP-230-25 and LP-12-450 will fit into a 1U space.  I've used them when they were called Flat Pack by MagneTek and they worked fine.

[DummyLoad]

https://toroid.com/Portals/0/205.5076.pdf


1.4" high x 3.2" dia. should fit. use the washers.


--pete

[nandrewjackson]

Try the power transformer for the standalone fender reverb unit. I've used it for several preamps, I've used it for 4-12ax7's at a time. It may require a 2 space rack unit though.

[Captain chunkulus]

The fender reverb transformer looks like what I'm looking for. Thanks for that.

[Captain chunkulus]

So I bought one of those standing alone fender reverb trannies. It says 306v dc. I'm assuming that's after rectification? I'm using a full wave rectfier for my build.

Try the power transformer for the standalone fender reverb unit. I've used it for several preamps, I've used it for 4-12ax7's at a time. It may require a 2 space rack unit though.

[PRR]

The Hammond item has more traditional specs. 237 V 50mA AC, which is indeed liable to peak-up then sag to something over 300V 27mA DC. Plus 6V 1A AC for heat.
https://www.hammfg.com/files/parts/pdf/290WX.pdf

[Captain chunkulus]

I hear ya, I was just wondering if this other transformers specs are indeed 306vdc after rectification or if it's 306v ac. The data sheet says 306v dc which I'm assuming means after it gets rectified.

[sluckey]

The data sheet is very specific... 306vdc at 27mA dc with a FWB. Says nothing about AC voltage for that winding, but you would need approx 216VAC to produce 306Vdc with a bridge.