Select power transformer for guitar rack preamp

[Rod]

Hello!

How do i select a power transformer for a rack preamp project?

Im thinking about using 6 to 8 preamp 12ax7 preamp tubes, it also has about 3 or 4 relays.

what is the normal voltage used by relays?

I think that 12ax7 heaters work it 6.3 VAC, right?

[The Dude]

This might help.

http://www.audiomatica.com/tubes/12ax7.htm

Typically, 12AX* tubes are wired parallel filaments and operate at 6.3V and 300mA per tube. That doesn't mean you can't run series filaments if you like. There are all sorts of relays out there with different voltage and current specs. Best thing to do is look up the datasheet for the relay you intend to use.

[loudthud]

When you say 6 to 8 12AX7 tubes, do you mean 12 to 16 triodes, or just 6 to 8 triodes ?