[Amps] Triode Amps

[gudguyham at aol.com]

The Palstar version of Commander was always   Don Kessler.  There was about one full run of the line sold and I don’t believe the second run ever went into production.  I have two of the Palstar 2500’s and I had an issue and got no satisfaction.  WE are pretty much alone and are going to have to fend for ourselves.  I haven’t checked the schematic but you can sure use a generic transformer for the filaments.  There are tons of 12.6v transformers out there that with a little to no tweaking of the primary voltage you can land 13.2volts on the three filaments total.  If you use a 12.6. 4 amp rated transformer on 1 tube, the filament voltage will be spot on.  For 3 tubes you’ll need a 12amp 12.6v transformer.  If it’s a tad higher you can tweak the input voltage with a high wattage chassis mount resistor.   The other option is to see if an old 2500e transformer is kicking around.  I assume you have throughly tested that transformer before you condemned it?  

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On Thursday, December 2, 2021, 5:08 PM, AJ <iamfromcanadaalso at gmail.com> wrote:



My current issue is with a Palstar 2500E which is a totally different
beast compared to the previous Commander versions. Only a handful of
them made according to Paul.

It has three 3CPX800A7's in it. The plate transformer is twice the size
of the early Commander 2500E.

So make a long story short. . .

Filament trans primary open.
Filter caps bulged.
Diodes shorted
Tube filaments open
Step start contacts welded.

I have yet to test the plate transformer, I do not have any specs on
it. There is no part number on it. I have contacted Paul at Palstar he
has no info as that product line was sold.

I have sent and e-mail to the owner (not positive if I have the correct
persons info) of the Palstar design; nothing back as of this time.

If anyone on here knows how to contact the current owner of the Palstar
design please let me know off list.

Thanks AJ___ VE3HJ


On Thu, 2 Dec 2021 16:19:09 -0500
"Tim Duffy" <k3lr at k3lr.com> wrote:

> My favorite triode for 1500 watts all day is a single 8877. 4KV and
> 30 watts drive.
> 
> Used 8877s exist and are more than capable for long lives. Some of
> the 8877s at K3LR have date codes from the 70s... still going strong
> 
> 73
> Tim K3LR
> 
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Peter
> Voelpel Sent: Thursday, December 2, 2021 4:16 PM
> To: 'Kim Elmore'; amps at contesting.com
> Subject: Re: [Amps] Triode Amps
> 
> Eimac specifies 890W for a single tube at 3.5KV plate voltage and
> 740W at 3kV.
> 
> 73
> Peter, DJ7WW
> 
> -----Original Message-----
> From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Kim
> Elmore
> 
> 
> The 3-500Z is an excellent tube, but 1500 W isn't reasonably
> available out of a pair, even at increased plate voltage
> 
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> 

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