Toroidal transformer on tube amp

[nigelwright7557]

I have used toroidal transformers extensively in valve amps.
First transformer drops mains to 6 volts for heaters.
Next transformer steps back up 6vac to 200vac to get valve B+.
Output transformer uses a 12vac mains transformer to output to speaker.
OK not highest of fidelity but sounds good to me.

 

[kodabmx]

I find the fidelity is excellent, especially using series connection of two toroids. Clean sine waves up to over 150kHz, and 20kHz square looks so good I had to check that I wasn't looking at the source! My friend even picked the toroid over the Hammond 1650N in listening tests.

 

[Dinolobe]

Would you mind sharing more information about your amplifier ? I would love to see a complete schematic. What kind of valve do you use ?

Shipping prices is what held me from buying Antek transformers. Sadly, triad doesn’t make suitable power transformer for regular tube use...

 

[Lingwendil]

Toroids work well, and work well even as OPT if chosen properly with some lower impedance tubes-

6N2P/6CW5 design with toroidal outputs

I've used them in a handful of builds, and they work as well or better than audio specific transformers in some applications, so long as you understand their limitations and are willing to work around/within them.

 

[kodabmx]

Would you mind sharing more information about your amplifier ? I would love to see a complete schematic. What kind of valve do you use ?

Shipping prices is what held me from buying Antek transformers. Sadly, triad doesn’t make suitable power transformer for regular tube use...

https://www.diyaudio.com/forums/tubes-valves/331934-6p45s-ppp-monoblocks-5.html#post5822179

The power supply for the output stage is in the fifth post. I use DC boost converters to get -110V for bias supply, and 560V for the VA/PI/driver stages.
The VPT230 series makes 300-320V depending on size and load, 600V with a doubler.
The VPT12 series make great heater transformers as well as outputs.

In my amp, I'm using a VPT18 160VA and full wave with shottky diodes to get ~12VDC for the heaters and DC boost converters and VPT18 250VA as OPTs

 

[egellings]

I repaired a Marantz 8B that had a burnt out power transformer. I asked Toroid Corporation to twist me up a 150VA toroidal transformer with the same windings / voltages as the original EI-cored xfmr had. It barely just fit into the place of the original. Amp sounds fine and is slightly more powerful due to the voltage regulation of the toroid, which is better than that of the EI-cored transformer.

 

[kodabmx]

Toroids work well, and work well even as OPT if chosen properly with some lower impedance tubes-

Check out https://www.diyaudio.com/forums/tubes-valves/331934-6p45s-ppp-monoblocks-5.html#post5822179

I'm getting 112W at 30Hz with the series connections. Sure, you need twice as many transformers, but the sound is excellent, and it's still cheaper than proper tube output transformers!

 

[multi]

I just bought 10 Toroids power transformers $US 14.00 each for 811 A amps from CHina

0nly problem shipping was US250

 

[bullpeters]

I agree with the Chinese torriods. Lots of voltage/current variety and lots of taps. Surprised at the shipping tho. I regularly get Asian air freight, if my wife was here she would know but it fast and cheap, fast and cheap.
Never had need to question the quality

 

[multi]

I had had a lot of trouble with Australian made toriods, most have gone up in smoke, but they do no replace, some even did not last 3 months.
The Chinese one's even have better better voltage regulation
Bull peters;Could you let me know how to find IT
I think some firms must have contracts with DHL

Phil