[Amps] Project for 8122 tubes

[jeremy-ca]

Not that Ive ever noticed. I have some used ones with late 60's date codes 
that are fine. I also picked up a distributed amp with 13 NOS 1983 date 
codes recently. They were all fine after a 5 minute warm up when I then used 
the original National test jig to match them. Got nice prices on Ebay.

The Eimac 8122W often has a much higher bias requirement than the RCA and is 
out of range of the bias pot. Its a simple matter to move the range from the 
stock -25 to -45V up to -35 to -55V. The Eimac has a bias range about half 
that of the RCA so they still require matching.

Carl
KM1H



Carl
KM1H


----- Original Message ----- 
From: "Pat Barthelow" <aa6eg at hotmail.com>
To: <amps at contesting.com>
Sent: Tuesday, August 14, 2007 12:42 PM
Subject: Re: [Amps] Project for 8122 tubes


> folks:
> Are 8122 Tubes that have been in storage for possibly Decades without use,
> likely to have internal gas problems?
>
> Sincerely, Pat Barthelow     aa6eg at hotmail.com
> http://www.jamesburgdish.org
> Jamesburg Earth Station  Moon Bounce Team
> http://www.cq-vhf.com
>
>>From: "sulai je" <7z1sj at jeeran.com>
>>Reply-To: 7z1sj at jeeran.com
>>To: <amps at contesting.com>
>>Subject: [Amps] Project for 8122 tubes
>>Date: Tue, 14 Aug 2007 13:03:08 +0300
>>
>>
>>Hello
>>I had some RCA 8122 tubes in my junk box since long time. Thinking to use
>>them in a homebrew project so I start to search for an amplifier project!
>>Either to UHF or VHF . HF Googling the net yields a zero project for those
>>tubes.
>>
>>if any on can help with schematic and more info I will be appreciated in
>>advance .
>>73s de 7z1sj Sulaiman
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