Newbie PS questions

[Hilly-wa]

A few PS questions from a newbie, apologizing in advance if these have already been covered in past posts. These questions relate to a 6c45 spud. (I figure I'd start my learning process with something simple.)

I have a power transformer with a single heater winding. Can I parallel the heaters of the rectifier (6CA4 or 6X4) and the two 6C45s from the single winding? Or do I need to keep the rectifier heater separate?

If I need a separate filament transformer, should it be used for the triodes or the rectifier heaters?

Or does it make sense to go with a SS rectifier scheme and use the 6.3vac on the power transformer for the spuds?

Also, is it preferable for each tube have its own L-C filter fed from a common C, or does a single C-L-C or C-L-C-L-C filter feeding both tubes make more sense?


Thanks in advance,

Ed

[kevinkr]

You can safely use the 6CA4 (I didn't check the 6X4) with the 6C45 on the same filament winding providing the following conditions are met:

• The sum of all the filament currents is less than or equal to the rating of the 6.3V filament winding on the transformer. (AC filament operation only - derate ~30% for dc filament operation, not really needed in this application.)

• Voltage on the cathode is less than the filament to cathode breakdown rating which is 500V.

If the filament winding is center tapped you can either ground it or elevated it 40 - 50V above ground to reduce noise coupling between the filaments and cathodes of your 6C45s. Otherwise use a pair of 100 ohm resistors connected in series across the filament winding - use the center connection between the two as a pseudo center tap for this purpose.