Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Leevi on October 09, 2011, 12:57:00 am

Title: PT without 5V secondary
Post by: Leevi on October 09, 2011, 12:57:00 am

I should add a tube rectifier (GZ34) to an amp where is not a 5V secondary.
Is it OK to drive use it with 6.3V? An alternative solution is to use 2 x EZ81?
/Leevi

Title: Re: PT without 5V secondary
Post by: DummyLoad on October 09, 2011, 01:29:48 am

use 2 x EZ81. try to stay within your PTs 6.3V winding current rating. alternatively you could add a 2A 5V transformer.

--DL

Title: Re: PT without 5V secondary
Post by: phsyconoodler on October 11, 2011, 10:23:38 am

If you need to dump some voltage it's better to use one of the many voltage lowering circuits rather than pop in two power sucking rectifier tubes.
  Zeners,mosfets,resistors on the center tap.All take up less room than a couple of tube rectifiers.

Title: Re: PT without 5V secondary
Post by: Colas LeGrippa on October 11, 2011, 10:50:40 am

this is very interesting........ any circuit diagram with a mosfet available  ? and what method is considered the safest ? resistor, mosfet or zener ?

Thanxxx

Colas