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Re: [Amps] Triode Amps

Subject: Re: [Amps] Triode Amps
From: Alek Petkovic <>
Date: Fri, 3 Dec 2021 10:53:46 +0800
List-post: <>
I'm about to rebuild the power supply in my 2500.

When I do, I'll be cutting a hole in the bottom of the amp wnad then making a cover plate, so the power supply can be more easily accessed in the future.

Also, I'll check to see if the same modification that Phil, VK6GX did to his amp, is necessary. He found that one tube was getting the bulk of the cooloing air. He modified the metalwork a little and know the air flow is equalised.

Hope to be doing that job right after Christmas. Got a couple of jobs on the worbench that should be out by then.

73, Alek, VK6APK.

On 3/12/2021 1:55 am, gudguyham--- via Amps wrote:
Commander amps are high on my list of most popular.  They are built well and everything is at or beyond standard for use.  Heavy duty transformers that don’t go bad. 
 I’ve never seen a bad one.  Major problem with Commander amps is very poor documentation and schematics.  There were several renditions of the 2500 but the model number or 
designation never changed..  Original  units used open frame antenna relays, later units had vacuum relays.  The TF decks are all basically the same.  The tubes are 
expensive if you need them. If you’ve been hoarding 3cx800’s and have a decent supply these amps are a good buy for you.  Reliability is good on these amps.  Most problems 
are minor and end up being on the control board.  The power supply is buried under the RF deck and that requires the RF deck to be removed completely from the chassis.  Getting to the 
power supply is 3 times as difficult and time consuming as the repairs to it.  Most original power supplies are still good today.  I recommend only rebuilding the supply when 
absolutely necessary.

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On Thursday, December 2, 2021, 11:16 AM, Jay Sturtevant <> 

If I remember correctly, you helped me with a spare filter cap. board for my 
Commander HF 2500. Thank you!
What is your opinion of the Command Amps available on the used market today?
Jay, K2ZT

On Thu, Dec 2, 2021, 10:33 AM Steve London <> wrote:

For a jaw-dropping experience, go to

$2499.95 for a 3CX800.

Makes RFParts look like a bargain at $1397.91.

The best deal may be a used Alpha 87A if the tubes are good.

Steve, N2IC

On Thu, Dec 2, 2021 at 7:09 AM gudguyham--- via Amps <>

It seems that all the European amp company’s use Tetrodes.  None use
Triodes.  All the Japanese companies went solid state.  Most US companies
are defunct.  The last man standing in the US that still uses Triodes is
Ameritron.  They make a full line of all Triode based amps.  They support
the following tubes in there line up.  811a, 572b, 3-500zg, 3cx800, 3cx1200
and 3cx1500.   There is something there for everyone.  Now if you want a
used amplifier that opens the door to similar tubes that Ameritron uses by
quite a few amp companies that are long out of business.  There’s some nice
Triode amps out there that are still in good condition if you look around.
The major problem is that “ GOOD” triode tubes are very expensive.

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On Thursday, December 2, 2021, 8:48 AM, AJ <>

Looking for info on manufactures of currently made QRO triode amps.

Is there a list someplace with data on the net?

Does anyone have a compiled list?

I have looked at sparky.

Thanks AJ___ VE3HJ
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