|
Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
|
|
|
Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
|
In Reply to: Re: Ultrasonic AC for DHT Filament posted by Retsel on March 6, 2003 at 10:56:06:
the voltage drop should be DC current * DCR... do be aware you need to use the working temperature DCR and not the room temp DCR.also i suppose the choke should be sized to provide a multiple of the hot filament resistance at say 20hz....
so for a 2a3, we have a 1 ohm hot resistance so say we want 5 ohms at 20 hz... which is 40mhy @ 2.5A... thats a pretty big choke. i suspect you can go smaller than that, since what i think we are trying to avoid is the high frequency current travelling through the filter cap...
a more reasonable guess is 60hz and a multiple of three which gives us around 7mhy.... probably close to what you have.
as it stands with the average 10,000 mic cap across the filament, we get nearly 50% of the current travelling through that cap... and increase in impedance should help.
dave
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: Ultrasonic AC for DHT Filament - dave slagle 03/6/0311:49:59 03/6/03 (2)
- Re: Ultrasonic AC for DHT Filament - Retsel 12:36:07 03/6/03 (1)
- Re: Ultrasonic AC for DHT Filament - dave slagle 18:20:36 03/6/03 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2026, Audio Asylum, all rights reserved ]
