Tetrode amp: Power Supply Rebuild finished

[Naysayer]

Amp seems happier with the FW bridge (instead of doubler) and new tranny (Heathkit 54-30 1800vac @ 400mA). Amp still on worktable and I must close it up & move it to operating location for more testing. Noticeably lighter without the 16A filament winding despite having 6 separate transformers. Welcome to Tetrodes.

Summer in the City means Con Edison decreases everyone's Electric to 105vac . Had me running in circles for a bit. When everyone puts their AC's away, maybe 110v will come back. Still, the PO I'm seeing is an improvement despite the low voltage.

there will be more to come,

neil, n2eye
New York City

 

[Naysayer]

Cannot escape Amps x Volts = Watts
Need more Iron.
Good lesson learned.

 

[nomadradio]

Need more Iron.

And/or a big Variac.

73

 

[Naysayer]

4cx300a amp w/ Tetrode boards:
Awaiting delivery on new caps for HVPS. Going from 180uF to 330uF @ 450v

Also scrapped the entire Tank circuit / band switch for a small La Pointe roller plus the separate Eldico 10M coil on the Tune side. The switch to FWB and new plate transformer increased my max Plate current so now I'm swapping caps.
These rollers have a spring-loaded pin on each end of coil. I used the Tune side contact to short the brush contacts when using the 10M coil. Is there any use for the remaining spring-loaded contact on the Load side of the roller coil?

I read online that roller coils turn black from the unused section being unconnected but no info on how to terminate the far end of coil.

Global warming makes Summer in the city dangerous. .

neil, NYC
n2eye

 

[Naysayer]

Kinda like a journal entry at this point but here goes another.

Upon HVPS rebuild I found my plate current metering was faulty.
I did not need a meter shunt. Stupid mistake # 173. Affects all prior plate current readings by making them too low, by a lot. Better late than never .

The low plate current fake did however, prompt me to move from Doubler to FWB and replace the filter caps so it worked out eventually. Data sheet on 4cx300a say 250mA per tube max plate current for ssb and 150mA carrier with anywhere from 1kv to 2.5kv on plates so I can almost power these tubes to their max. I can call that circuit protection, lol.

I'm seeing steady ssb peaks over 410mA and the plate voltage a lot stiffer from 330uF caps which are 1/3 larger in size from the 6x 180uF's I had before. Caps received were not Asisi. Seller sent Nippon Chem Con instead. Used 110k 4w bleeders. Need to figure out a better Load cap but the roller fits much better than the clunker of a band switch. Smaller footprint too. It's working good a few more tweaks and I'm done. Time to disappear for a few years again.

But I'll post Pics first. So hot in NYC. 24/7 AC feels like confinement.

73's
neil, n2eye