Transformer with no bias tap?

[Axtman]

I picked up a NOS power transformer at my local thrift store. It has 440v-0-440v, 6.3v-0--6.3v, and 5v taps but no bias tap. How can I use it in a tube amplifier without a bias tap? BTW the transformer is a Stancor P-6143 and I tested it.

[The Dude]

You could tap off of the B+ winding and knock the voltage down with a cap, resistor, or combination like some of the old Marshalls. Or, you could use cathode bias.

Here's an example of the former:

https://mhuss.com/MyJCM/JCM800_2204.gif

[J M Fahey]

Since it is a center tapped full wave rectifiedn transformer, you *do* have "bias taps", only 440V instead of 50-60V

Use exact same circuit but size resistors up to attenuate higher AC voltage.

[the fatch]

www.valvewizard.co.uk.bias/html

[g1]

www.valvewizard.co.uk.bias/html

That link didn't work as there's a slash instead of a dot. Here it is again: http://www.valvewizard.co.uk/bias.html

[Jazz P Bass]

I made it into a pdf in case the page ever 'disappears'.