Transformer Sources

[Alex/Tubewonder]

Torroidal power trannys would be great, but from my understanding torroidal output trannys don't work very well with DC magnetization (high DC offset on a push pull output or the idle DC on a SE amp). Someone correct me if I'm wrong here?

For SE you need an air gap in the core - rather difficult to impelement in bagel shaped coil of iron tape, easy to do in EI core.
The DC imbalance becomes an issue when net DC current causes high enough magnetic flux to get the core near saturation ( I would imagine). I think any low level magnetization caused by imbalance in PP idle currents (these usually are in the range of few mA) will be neutralized as soon as AC signal is applied. I have not experienced any such problems with my OT bagels yet. I think the "dangerous" setup would be toroid OT in cathode biased PP with common cathode resistor to both output tubes.

[defaced]

I have seen toroidal OTs with slits cut in them to provide an air gap. I have also seen amps with servo controlled bias to minimize DC through the primary of the toroidal OT. I think if you have to jump through that many hoops, it's not worth screwing with. But that's the engineer in me.

[TheTinMan]

I built 2 Blackface Princeton Reverbs, 1 with Mercury Magnetics iron and the other with transformers from Hoffman Amps. I don't think that there's any significant difference in tone. The MM PT put out slightly higher than vintage voltage, looked prettier, and cost more.

My only experience with Allen Amps is an OT in a Tweed Princeton (5F2-A) circuit. HUGE increase in frequency response, especially bass. Unfortunately, I actually liked the tone of the cheap little OT that was in there originally better - small cab, 10" speaker & no bass control.

2CW

Chip

[Wombaticus]

I built 2 Blackface Princeton Reverbs, 1 with Mercury Magnetics iron and the other with transformers from Hoffman Amps. I don't think that there's any significant difference in tone. The MM PT put out slightly higher than vintage voltage, looked prettier, and cost more.

My only experience with Allen Amps is an OT in a Tweed Princeton (5F2-A) circuit. HUGE increase in frequency response, especially bass. Unfortunately, I actually liked the tone of the cheap little OT that was in there originally better - small cab, 10" speaker & no bass control.

2CW

Chip

The Allen Amps TO-22 works very nicely indeed in a 5E3 circuit. It's wound for him by Heyboer.

[Wombaticus]

Chip/Tinman --- Richmond, UK, Richmond, BC, or Richmond, VA?

[TheTinMan]

Wombaticus - Richmond, Old Dominion a.k.a. the Commonwealth of Virginia. I've been to Richmond, England but didn't know there was another in British Columbia. There's also a Richmond, California.

[daz]

seriously think about trying one of the ones bruce mentioned....magnetic components. they are probably the cheapest of the bunch but no less quality than any of the others. I replaced a hammond with a heyboer, then finally replaced that with a mag comp and i believe the mag comp is the best of the 3 to my ears. But it's close....they're all good. So why pay more?

[Ronsonic]

I haven't tried these myself. So I'm just reporting impressions instead of experience, but the next time I need trannies I'm going to try Magnetic Components. The test impressed, and I like the prices. Paper-Vs.-Plastic