Choke Load PS

[leadtower]

Has anyone used a Choke loaded PS for the GSG? I have a PST wound by Heybeor with 400-325-250-0-250-325-400; 5v 3amp and 6.3 3amp secondaries; 100 ma. I used it on a DIY pre-amp with a Hammond 193c 20hy 100 ma choke. The cap after the choke is a 100 uf oiler. I used a 6ca4 full-wave rec.
Any possiblities this would be workable does anyone know?
Thanks guys.

[SDS-PAGE]

I thought the GSG PS already had a choke (1.5H) in it. Was your question whether or not your choke would work with the amp? Also, I believe you need two 6.3 vac windings for the circuit.

[leadtower]

Yes but the PS is C-L-C. I was wondering if an L-C filter would work. Also if my PT would be useable with the existing windings. I have two filament trannies from Hammond if I need them. I like the idea of a choke loaded supply. And might as well try to use what I got here.

[EWBrown]

The other term for this is "choke input" for L-C PSUs.

The PSU's ultimate output voltage depends on teh choke's inductance as well as DC resistance, and the total DC current demand.

It can be "fine tuned" by using a smaller value cap (like 630VDC Solen Fast Caps), if the voltage needs a small amount of teaking upwards.
Should work fine.

Note that some chokes used as the input element may ehibit some mechanical hum or buzzing, and they are more likely to throw a 120Hz magnetic fleld. THis should not be as much an issue with the enclosed type chokes in the 193 series, as it would be with open frame chokes in the 156 series.

/ed B in NH

[leadtower]

Thanks Ed; I am trying to model this on Duncans site. I'm only doing it for giggles and to use the stuff i have. I have no idea if it will be a better or different sound. I know it worked well on the pre-amp.

[TerrySmith]

I tried a choke input psu with a new C-354, it sounded like a seat belt buzz-zz-zzer on a '73 Chevy. :o Yellow_Light_Colorz_PDT_43 :parp:

[leadtower]

Terry; thats the problem; the '73 Chevy was known for that.

Why should it buzz if you use a quality choke? people always told me that the ST 70 PT buzzed. The problem went away after installing the DIY board and the SDS PS. I don't know which part was responsible for eliminating the buzz.
But it's gone.

[EWBrown]

The open frame chokes are more prone to buzzing, and for throwing a 120 Hz magnetic field into any other nearby transformers and even inducing EMF "nasties" into nearby tubes :o
THey're not really suitable for choke-input PSUs

The enclosed (and better yet, potted / vacuum impregnated) chokes are less prone to suffering from "the nasties"....

/ed B in NH

[hembrook]

I have a noticeable hum in my GSG, which uses a 156 series open frame Hammond.