[Amps] Triode Amps

[Alek Petkovic]

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.
>
> Sent from the all new AOL app for iOS
>
>
> On Thursday, December 2, 2021, 11:16 AM, Jay Sturtevant <k2ztdx at gmail.com> wrote:
>
> AJ,
> 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 <n2icarrl at gmail.com> wrote:
>
> For a jaw-dropping experience, go to
> https://mfjenterprises.com/collections/ameritron/products/383-0800-a7-2
>
> $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.
>
> 73,
> Steve, N2IC
>
> On Thu, Dec 2, 2021 at 7:09 AM gudguyham--- via Amps <amps at contesting.com>
> wrote:
>
>> 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.
>>
>>
>> Sent from the all new AOL app for iOS
>>
>>
>> On Thursday, December 2, 2021, 8:48 AM, AJ <iamfromcanadaalso at gmail.com>
>> wrote:
>>
>>
>> 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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