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Re: [Amps] Triode Amps

To: AJ <>, <>
Subject: Re: [Amps] Triode Amps
From: gudguyham--- via Amps <>
Reply-to: "" <>
Date: Thu, 2 Dec 2021 22:44:57 +0000 (UTC)
List-post: <>
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?  

Sent from the all new AOL app for iOS

On Thursday, December 2, 2021, 5:08 PM, AJ <> 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" <> 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 [] On Behalf Of Peter
> Voelpel Sent: Thursday, December 2, 2021 4:16 PM
> To: 'Kim Elmore';
> 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 [] 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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