the best transformer rail voltages for gainclone?

[araven]

Hi,

I'm currently building a gainclone using a LM4780, and was wondering what the best transformer spec would be?

I like the look of the THD+N graphs (and other graphs) when using 35v and 8ohm speakers. The problem is, i want the amp to be flexible and i can't gaurantee that I won't use speakers with a lower impedance at some point.

Also, what's a good power rating to use? At a guess i would assume a minimum of about 200VA.

Thanks,
Andy

 

[araven]

Forgot to mention, I currently already have 2 suitable toroids in my spares box to choose from.

1. 22v 225VA (which should deliver about 31v after rectification under load)
2. 25v 300VA ( 34.5v after rectification under load)

Thanks,
Andy

 

[jaycee]

Either would do, really. I'd go with the 25V 300VA unit, just make sure you dont crank it when used with 4 ohms