Hello Dave!
sorry, but I can't agree in your explanations. There is strawing for sure!
But I would never call it a communistic phenomenon. I use amps with 2x
GS35b. It took a while and a number of tubes to find a matched pair. See:
www.hoeppe.name . It is as difficult as it is with tubes produced in other
countries. I tried Thomson, Eimac, Siemens....all showed strawing!
Concerning the quality, you can be sure that you find the finest materials
inside russian tubes. Regard the heating power for a GS35b. It is hard to
find a 1,5 KW tube emitting with such a small heating power. This is a
result of excellent materials inside! Russia is rich of sources, and they
did not care about the prize when choosing the materials for military
equipment. The best was just good enough! Only some newer (!) tubes are told
to have less quality materials on the cathode. The tube life is also
fantastic.
I think the discussion about the maximum plate voltage does not lead to a
result. Extreme voltage may work in some conditions with some tubes, no
doubt. The question is if this is the way I want to go to get more power. I
published a 144 MHz linear with GS35b in Dubus magazine 1996. It has been
reproduced worldwide, and I got feedback with parameters. Many builders
proudly report of "much better results" by using more voltage. But there are
so much other nice high power tubes on the market, so why kicking a tube far
over the limit? If one normal driven GS35b is not enough, I prefer another
kind of tube....or two! I talked to many russian amp builders in the past,
most of them recommended not more then 3600 volts. So if you think
overdriving a tube is a good way to obtain power, go ahead. If you like "no
matter what" performance, I would go another way...
73s de Tom, DJ5RE in Bavaria
----- Original Message -----
From: "David H Craig" <davidhcraig@verizon.net>
To: <dezrat1242@yahoo.com>; <amps@contesting.com>
Sent: Wednesday, December 16, 2009 8:05 PM
Subject: Re: [Amps] Russian Power Tubes
> Russian (USSR) specs are not the same as Eimac or other hi-quality
> manufacturers. There is, for example, not even a published figure on
> cathode input impedance. That said, stick to your sheet specs and build a
> GS35b with 3kv on it- you won't get the performance you expect. As for
> me,
> I'll stick with 4400v, which is 146% out of rating. BTW, there sure are a
> lot of "out of spec" GS35b amps out there. Must be Communist tube quality
> control.
> 73 Dave N3DB
>
>
>
>> On Tue, 15 Dec 2009 21:22:38 -0500, "David H Craig"
>> <davidhcraig@verizon.net>
>> wrote:
>>
>>> I guess empircal evidence isn't germain to this discussion....
>>> must
>>>be flat-earth "theory." I have some PE friemds that run close to 5KV
>>>on
>>>the plate of a pair of GS35Bs on 50 MHz... again. I assume it irrelevant
>>>to
>>>the "theory" gods.
>>> Dave N3DB
>>
>> REPLY:
>>
>> You are right, it is not relevant and I'll tell you why.
>>
>> Manufacturers often make production runs of a particular part which can
>> and do
>> vary slightly from one run to another. Just because one run of a part
>> will
>> withstand say, 133% overvoltage, does not mean the next run will, even
>> though
>> all parts meet specs. Wise designers know this and stick to the specs.
>>
>> 73, Bill W6WRT
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