choke ?

[mr.jetski]

hi all,

pt 350-o-350 full wave rectifier 490v max
now, what choke to use if max idle current consumption is 225ma +/-
i would like to choke it before the OT

thanks

[tubeswell]

My guestimate is 250mA (allowing a bit of leeway for output tubes to draw more current)

[daz]

Not to hijack the thread, so please everyone don't answer me. Maybe one answer thanks....what is the benefit if any of putting the choke before the OT and first cap? How does it differ in feel or sound?

[loudthud]

We're talking about two different circuits here.

Rect->choke->cap-OT = Choke input filter

Rect->cap->choke->cap-OT = Pi filter

A choke input filter will really knock down the B+, to about 310V with a 350-0-350 PT. The result is a pretty stiff B+ with high current capability. It takes a pretty big choke and below a certain current, the B+ will rise up to 490V.

A Pi filter can give you really low ripple. So low the amp will sound too clean. Good for Bass amps though. Big caps = big solid bass. Sag is lower than normal.

Duncan's PSU Designer is the tool to use. You don't need a very big choke if you use big caps like 100uF to 200uF.

[mr.jetski]

thanx all,

hi pete, how's it.

daz, its a pi filter super quiet w/ultralinear OT so when the tubes saturate and distort it is a real tight edge sound or so i think

loud, hi. using the pi w/ultralinear EL34 = 40w. trying to do a hotrod brown face 2 channel vibroverb but i need engineering help.
using psud II

HAPPY NEW YEAR