Filament voltage .. AC/DC?

[GnG8d]

Is there an advantage of one over the other for the heater voltage?

 

[office888]

AC can produce filament hum.

 

[GnG8d]

Is a simple choke sufficient for filtering after rectifying? Regulation?

 

[Kamikaze]

AC filaments if directly heated use a centertap on the transformer to complete the cathode circuit. They have extremely tiny amounts of hum.

I've heard DC will wear out a filament quicker due to more emission on one side of the filament. Not sure though.

Standard practice on most tubes is to use AC and sleep at night like a baby.

 

[GnG8d]

How about indirectly heated? Stiil AC centertapped?

 

[Kamikaze]

How about indirectly heated? Stiil AC centertapped?

Some like the 12AX7 are but it does not complete the cathode to ground circuit as in directly heated tubes.

 

[GnG8d]

So a YC156 for example could use a center tapped xformer, center tap to ground, a pair (or single) bifilar choke, and delta fed Rf through the caps.

 

[BJ radionut]

WV7U YC156 Amp

359
You may have already looked at this...
If not this Gent builds some real killers.
All the Best
BJ

http://www.directivesystems.com/YC156.htm

This link may be a little closer to your needs...still looks like an interesting build...but the control circuits and warm-up controls seem a little tedious to my liking.

 

[GnG8d]

Good links. I saw another guy who was using 2 bifilars in parallel and it had me confused for a second, but it just dawned on me that he was increasing the amperage capacity.