Some of the best hf amplifiers were built by Viewstar. They had 3
different models with the small one PT-1000 using a single 3-500Z, then
the PT-2500 which had a pair of 3-500Z and the very rare one model
PT-3000A (only 5 of those produced) using a single 8877 tube with
factory QSK option installed with vacuum relays. The line was later on
sold to B&W but unfortunately it did not last very long there.
All 3 models of those amps were very well built and very reliable.
I have owned all 3 different models but now only have the PT-3000A which
is a very nice high power desk top amp. The only problem with it is
that I had to replace a padder ceramic cap used across the main tuning
cap on 160 and 80 meters and to replace the ceramic loading cap used on
160 meters with a mica type to prevent drifting of the loading when
operating rtty or am.
I certainly would not derated any hf amplifier when the problem is
with inferior poor quality tubes which was quite a common thing going
back a few years ago when the import tubes from say China were coming
in. We should blame ourselves for not wanting to pay the high prices for
better quality north american or European brands of tubes which were
available all along.
Just my 2 cents worth. Cheers from Fern VE7GZ
----- Original Message -----
From: "Tom W8JI" <w8ji@w8ji.com>
To: <Gudguyham@aol.com>
Cc: <amps@contesting.com>
Sent: Sunday, July 30, 2006 9:18 AM
Subject: Re: [Amps] Ameritron Amps
>> Tom, I am not aware of what amp you might be referring to
>> here, can you lwt
>> me know...PLEASE! Thanks 73 Lou
>
> When the Chinese were making 3-500Z tubes with regular glass
> and holes were sucking in the sides, Rich concluded it was a
> VHF parasitic that couldn't be seen or measured. This VHF
> oscillation supposedly caused dielectric heating of glass at
> VHF.
>
> Paul Hrivnak of Viewstar, Palstar, Vectronics fame was
> building a single 3-500 amp using that particular Chinese
> tube. He changed to nichrome suppressors and tubes kept
> right on failing.
>
> 73 Tom
>
>
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