Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on January 05, 2017, 07:41:49 am

Title: G2 alternative PS (one other one) - Is this feasible ?
Post by: kagliostro on January 05, 2017, 07:41:49 am

Some time ago I asked about how to feed G2 if the PT hasn't a dedicated winding but the tube require low G2 voltage respect B+ (tubes like EL504 ... GU50 ... 807 ...)

and the disquisition ended with this circuit (by courtesy of PRR)

(http://el34world.com/Forum/index.php?action=dlattach;topic=20467.0;attach=59871;image)

--

Yesterday night one alternative come to my mind

but I'm not sure it is feasible because of the presence of the virtual ground (220R resistors) and Elevated Heaters

and because I'm not sure this way some noise is injected on G2

the idea is to use a 220V / 15V transformer connected backward and feed it with 12.6V from the 1625 heater winding
(so I have 185V AC that rectified and leveled arrive to 259V DC)

(http://i.imgur.com/3DVHkoa.jpg)

This is the schematic of the amp

(http://i.imgur.com/CCj7jlj.jpg)

Please, which is your opinion ?

Molte Grazie

Franco

Title: Re: G2 alternative PS (one other one) - Is this feasible ?
Post by: sluckey on January 05, 2017, 07:46:05 am

I think it should work just fine.

Title: Re: G2 alternative PS (one other one) - Is this feasible ?
Post by: kagliostro on January 05, 2017, 08:55:29 am

Thanks Steve

Franco