[Amps] [ham_amplifiers] The quality of Chinese 811A and 572B

[Carl]

Which brand names does that manufacturer build the tubes for?

There are many complaints about quality and performance of 572B's in 
that they do not work well or reliably in amps that were designed to use 
the USA built Cetron tubes.

The main problem appears to be with parasitics. Ask your engineers if 
they have tested this and designed an appropriate parasitic suppressor 
compatible with their 572B design which is not the same as a 1970's 
Cetron.

If they can modify their tube design to be an exact equivalent to the 
Cetron that will solve most of the problems. The remaining one is 
quality control before the tube leaves the factory.

Carl
KM1H
----- Original Message ----- 
From: "Hsu" <hsu4qro at gmail.com>
To: <amps at contesting.com>
Cc: <ham_amplifiers at yahoogroups.com>
Sent: Thursday, November 13, 2008 10:20 PM
Subject: [ham_amplifiers] The quality of Chinese 811A and 572B


> Hello ,Guys!
>   When I became a ham operator in 1992, I often heard some  complaint 
> about the quality of Chinese 811A and 572B.Yeasterday, My friend  and 
> I  call the manufactorer  and talk with the engineer about this, they 
> are very surprise.As a engineer, they seodom to  communicate with the 
> user,due to the handicap of language and culture etc.Some standard was 
> different with the West.For example, Chinese 811A's Plate dissapation 
> only have 40W and with thin plate.If it run 60W Plate dissaption,the 
> life will be very short.
> Well, They decide to increase the tube  quality in next year. They ask 
> me to send this information here, and want to hear all the complaint 
> especialy  come from the tube amplifier's  manufacturer  about the 
> 811A and 572B,They want to make good winning like Chinese 3-500Z.
>  Thanks in advance!
>             73!Hsu
>
>