Tube DIY Asylum

RE: Transformer/Voltage Doubler/Damper Diode Questions

65.116.131.6

Tom Bavis

In Reply to: RE: Transformer/Voltage Doubler/Damper Diode Questions posted by Eli Duttman on February 08, 2011 at 20:20:29

I did a quick PSUD simulation and found 725 mA in the transformer with 140 mA DC from the doubler.

-BUT-

The 0.7A rating may be conservative - measure the winding resistance.

And you're not using the other secondaries to capacity. So that 176V secondary MIGHT be good for 1A or more.

Follow Ups:

Winding Resistance - How to Interpret? - FlaCharlie 14:36:13 02/09/11 (2)
I measured the primary (117v) and got 1.4 ohms. The 176v secondary was 5.9 ohm and the 97v was 4.4 ohm. Not sure how that relates to the amount of current available . . . ??? I definitely won't be using the full current rating of all the windings.

I was planning on using only one of the filament windings to power all the filaments. Not sure exactly what front end I'll use. Douglas (PakProtector) sent me some info on his PP 6CB5A project which will use 6BQ5s in LTP. I'm also considering 6SN7s and 6GK5s.

I'm not sure if I'll use the 97v winding or not. If I run the 6CB5As in pentode, I could use the 97v winding as a screen supply, which would draw very little current. Or I might use the 97v to power the front end tubes.

Any suggestions are welcome! My knowledge of design is minimal, at best.

I DO want to build something fairly simple - cap coupled, no interstage transformers, no CCS for now. As usual, I'll be trying to use scrounged parts. Output transformers will likely be pulled from a Pilot 654 receiver (PP 7591). They are 5.6k primary and pretty hefty. I also have a Scott 299A around that could also be a OT donor, I suppose. If this power transformer is unsuitable, I could also pull the PT from the Pilot or use one from a Sansui 1000A, which used a doubler circuit. I'd like to be able to make this one work though.

. . . Charlie
- RE: Winding Resistance - How to Interpret? - drlowmu 16:05:42 02/12/11 (1)
  Hi Charlie,
  
  Notice "Augmented Cooling" on the PT. Consider that some.
  
  What are the DCRs of the primary and HV secondaries?
  
  Jeff Medwin
  - Augmented Cooling?? - FlaCharlie 19:29:06 02/13/11 (0)
    Jeff - As stated above:
    
    "I measured the primary (117v) and got 1.4 ohms. The 176v secondary was 5.9 ohm and the 97v was 4.4 ohm. Not sure how that relates to the amount of current available . . . ??? I definitely won't be using the full current rating of all the windings."
    
    So, what does "augmented cooling" mean? I've never seen that term before.
    
    . . . Charlie

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