Sonic difference of an over-rated Transformer.

[marcoloco961]

What I am wanting to know is, if I have a Transformer for a particular build that was spot on as far as voltages, but had a higher mA rating then specified tranny for that build. Is there any real noticeable sonic differences in the amps sound. Like if I had a tranny that was 300-0-300 @ 450mA I wanted to use in an express build, would that be feasible, and still sound like a wreck?

[daydreamer]

Would it affect the ' voltage sag'? I would have thought so. From what I understand so far, bass frequencies draw more current so it would affect those first. I stand to be corrected though

Andy

[JamesHealey]

I built my liverpool using 250ma then changed to a 200ma the later sounded much better. No explanation

[Structo]

It depends on the amp.
Take the Fender Deluxe amp and sag when turned way up.
It's known for it's sweet overdrive tone and I'm sure a lot of that is from the power transformer.

A lot of the grail amps from yesteryear were not designed to turn up past distortion levels.
Most of those amps did not have a very robust power transformer for some reason. Cost was probably the biggest reason.

I think it bothered Leo Fender to no end when guitarists started turning his amps up to where the power tubes distorted.

He wanted a clean sound for guitar and steel guitars.

[Gaz]

Overrating a PT seems like a very archaic way of regulating the power supply, in that the B+ will sag less when you're slamming away with chords. This should yield less compression, and perhaps a punchier tone. If that sounds good to you, go for it!

The only potential downside could be that if you are operating a given set of power tubes at or slightly above their threshold. This is especially true with screens grids of EL34s, EL84s, 6V6s, and others. If the circuit is already putting the screens above their max voltage, and your overrated PT is not allowing the voltage to sag, then it's very very likely that your screens will over disspate and, well...melt!

Personally, I would not use such a transformer for a non-master volume amp, especially an Express, which tortures power tubes, despite its relatively conservative voltages. This is all exacerbated by today's less robust power tubes - especially EL34s. But hey, if you've got some Mullards, disregard everything I just said!

It seems to me that a over-rated PT would work well in a high-gain amp that is not 'square-waving' the power tubes into oblivion, and needs a tight punchy tone.

It also seems great for a non-master amp that does not drive the power tubes so hard, or would be operated more cleanly. I dunno, just thinking out loud here, but maybe you could do a KT88 express, those tubes wouldn't mind at those voltages. Good luck!

[marcoloco961]

Thanks for the input. I thought that some amp designs needed the sag more than others. But was not sure if the excess mA's would be a tone killer. No sense in building an amp with a certain sound in mind, and then find out after it's done that it sounds terrible.