Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Other Topics => Topic started by: Cree on March 02, 2020, 02:43:48 pm

Title: Transformer Spec's
Post by: Cree on March 02, 2020, 02:43:48 pm

Looking at this transformer, Classic Tone 40-18019 for a (F) Champ type build. IN the specs it says, 650v ct @ 70ma. Does this mean 70ma both sides of the center tap for 140ma total or does that mean 70ma total? If 70ma total hows does this power a Princeton Reverb?   :dontknow:

Title: Re: Transformer Spec's
Post by: sluckey on March 02, 2020, 03:49:53 pm

That means 70ma total, ie red to red can provide 650VAC @ 70mA. Looking at the same PT you see 6.3V CT @ 2.25A. That also means 2.25A total, ie green to green can provide 6.3VAC @ 2.25A.

A PR sucks the voltage down a bit to get all the juice it needs.

Title: Re: Transformer Spec's
Post by: pdf64 on March 07, 2020, 10:23:09 am

With a 2 phase rectifier as used in tube amps, at any instant the current can only flow in half the HT winding.
http://www.valvewizard.co.uk/bridge.html
So it might not even be rated for a continuous 70mA through the whole winding.