Balanced Power

[vizion]

Is balanced power (+60/-60 or +120/-120) good for tube amps ? Most desginers critically listen to their creations using regular power.

[Jeb-D.]

If you are inquiring about using symmetrical supply rails, it is rare in tube amps. There aren't N and P channel tubes, only N channel. Also, most are transformer coupled. So it is pretty much pointless to have a symmetrical supply as ground will make a better voltage reference than a negative supply rail. The only time you really see symmetrical supply rails is in OTL's (output transformerless) that are based on a totem pole type topology.

[vizion]

I have a regular tube amplifier that is hooked up to a balanced power transformer near the wall sockets. I'm just not too sure if the sound coming from the amp is what the designer has envisioned.

[leadbelly]

Originally posted by vizion
I have a regular tube amplifier that is hooked up to a balanced power transformer near the wall sockets. I'm just not too sure if the sound coming from the amp is what the designer has envisioned.

I'm not big on "visions". Why don't you listen to the amp with and without the extra transformer and see which one you like more, if you hear a difference.

[Wavebourn]

I use 75V+75V+15V (165V total) in my 300W/channel amps, but they are hybrid, i.e. contain tubes and transistors.

[leadbelly]

Originally posted by Wavebourn
I use 75V+75V+15V (165V total) in my 300W/channel amps, but they are hybrid, i.e. contain tubes and transistors.

He's talking about the use of an isolation transformer.

[Wavebourn]

Originally posted by leadbelly


He's talking about the use of an isolation transformer.

Ah, sorry!

Isolation transformer may be a good thing to eliminate horrible ground loops, but input transformers in power amps would be safer, i.e. Regulations require the green wire (Safety Ground) to be properly connected.

[Majestic]

as far as I was aware, balanced mains just reduced the 'grunge' coming in on the power line. (Does something else happen too?)

By all accounts this generally is reported to sound 'better'. And it's almost certain that the manufacturer would have designed and auditioned their product sans balanced mains input (given the very few households that would have it). But I, as a designer, would want to hear how my product held up in a 'normal' (somewhat sub-optimal) environment anyway (and design accordingly). If it sounded good there, it'd (surely) just sound better with balanced power(?)

[leadbelly]

Originally posted by Majestic
If it sounded good there, it'd (surely) just sound better with balanced power(?)

That's quite a leap. Got a technical explanation?

[Majestic]

Originally posted by leadbelly That's quite a leap. Got a technical explanation?

hmm, I would have thought the theoretical explanations would have been well known. The real question is whether the theory translates into any actual practical or audible advantages.

But a quick google turned up the following:
Tech stuff from Equitech (a Bal-pow manufacturer)
- Origins
- future
and a random review (the first I happened to stumble across) of one balanced power component

I'm sure there's plenty more -- both yay and nay -- out there too.