F2J power supply voltage??

[holminator]

I am gathering parts to build a F2J clone and I was wondering if it is ok to use higher voltage without to much modification to the original circuit. I have an big(600va) old transformer with one 30vac secondary winding, collecting dust...

Use regulated supply, to get the voltage down, but how much?

Unwind the transformer?

Or buy a new one?

[Nelson Pass]

The original is 23V DC, achieved with an 18V AC secondary. You can go a bit
higher without issues, but I think 30V AC should probably be dropped down
a bit. You could make a CRC filter in the supply that loses 10V on the
resistor.

[Zen Mod]

that amp is worth some trouble to make it right

either unwind , or buy new one

2 x250VA for dual mono ; 2x18Vac secondaries

or 500VA for both channels , 4x18Vac secondaries

[Lazybutt]

For an F2J, won't 2 secondaries be sufficient ?

2 x 250VA for dual mono ; 1x18Vac secondaries (each)
or 1 x 500VA for both channels , 2x18Vac secondaries

(Edit: or did mean the number of wires ?)

[holminator]

Thank you very much for the quick replies.

But, what would be the disadvantage using only one secondary winding?

Anyone happen to have some spare pcb by the way? Or i will just do p2p...


Kjetil

[Zen Mod]

@Lazy....

mea culpa !

off course that you are right

I meant on another FW amp , which use symm. PSU

in any case - VA numbers are still valid

[Lazybutt]

OK, Thanx Zen !

@Holminator: the disadvantage would be cross talk between left and right channel. I'd guess with a CCS, this is a minor disadvantage though

Now I'm wondering ...- all things being equal: if we have 2 secondaries in total in each case: is there any advantage at using one 250VA with 1 secondary per channel vs 1 x 500VA with 2 secondaries for both channel ? (like due to coupling of windings between each other) ?