Best 15-18W EL84 power transformer?

[Rick]

I may need to build a custom amp for someone and this has to have the very best of transformers, components, etc. What do you consider to be the best 15-18 W power transformer, also, what is considered to be the best output transformer? The amp I'm building is not a typical 15 or 18 watt design, but all existing prototypes work very well with the Weber W025130, which is a 275-0-275 PT with 5V, 6VCT, so something in that ballpark is required but I need absolute, rock solid reliability.

I've had a few of the 025130 units fail over the years and I'm not sure why, so I did a few things to the power supply design like adding anode load resistors or a cathode resistor to the rectifier, replacing the "hot switch" standby switches with a bypassed, direct to reservoir cap feed, soft switching standby, but I still want a rock solid, highest quality available power supply as the last thing in the world I want is this PT to fail because of poor quality construction.

So what is the BEST 18 watt PT? I want to stay around 275-0-275 HT winding so that the circuit design doesn't need any changes, if at all possible. Thanks for any serious contributions,
Rick

[Stevem]

Are we taking class A PP and will it be cathode , or fixed bias?

Does the future owner want real good dynamic range and large peak power, or us a amp a bit on the soft side more towards his / her needs?

If the amp will use just two or three preamp tubes than the Hammond 270fx with its 173 ma of current will have a good amount of that current left in reserve and allow fixed bias and class A if you want with real good dynamics.

[Phil_S]

A Stevem seems to suggest, the question is rather subjective at best. More information on the design and desired tone is bound to elicit better replies. If I just tell you a Stancor A-3804 is the best, that doesn't make it so, even though it is a much sought after transformer.

[Rick]

Are we taking class A PP and will it be cathode , or fixed bias?

Does the future owner want real good dynamic range and large peak power, or us a amp a bit on the soft side more towards his / her needs?

If the amp will use just two or three preamp tubes than the Hammond 270fx with its 173 ma of current will have a good amount of that current left in reserve and allow fixed bias and class A if you want with real good dynamics.

Yes it will be PP Class A or AB1(?) with a cathode bias in typical EL84 15-18 watt fashion. It will be running four preamp/PI tubes though, 3 as preamp and of course the phase inverter, so it will need ample current for 2-EL84s, 4 preamp tube sets of cathodes, and 5V and a minimum 2A for the rectifier filament, preferably 3A and the usual 2A or so for the preamp heaters. I think I may have found what I'm looking for in either the AC30 replacement by Hammond or else the Mercury 18W PT. The AC30 PT should be able to handle all the requirements with ease and plenty of capacity left over.

[RJ Guitars]

I had Edcor custom wind a set for me that I use for two hole EL84 Trainwreck builds. They sound great and are reasonable affordable. I generally sell everything to the TAG regulars at a pretty good discount... see what you think http://rjguitars.net/15_Watt_LP.html There is more info on the trannies on my web site and several build threads featuring these trannies over on the Trainwreck Discussion page here at the TAG forum.