Zero grid dissipation is no problem.
No grid current, no dissipation.
The Chinese 3CX1500A7 seem to be very reliable.
A company nearby uses 200 of them for about two years and so far no tube
failure.
Application is voltage regulator for a magnetron, where they replaced
QB4/1100 (4-400A) since the last factory (Amperex) stopped building those.
They pay 400US$ the tube in quantity
73
Peter
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Roger (K8RI)
Sent: Mittwoch, 21. Mai 2008 00:03
To: Amps
Subject: Re: [Amps] New Amps at Dayton
Bob Maser wrote:
> The new Alpha amp that runs a pair of 4CX1000A's is the 8410. This
> amp uses a 3.6KVA plate transformer.
>
The same 4CX-1000A used in the 30-S1? The one with zero grid dissipation?
That's the tube I've always said I'd never use in anything because it's so
fragile or have I missed something?
> Also at Dayton Emtron introduced their new DX2B which also uses the
> 4CX1000A. They are in the process of introducing the DX3B which will
> run a pair of the same tube. Looks like all the manufacturers of amps
> are scrambling to replace the Russian tubes. The 4CX1000A can be
> replaced by the 4CX1500B, which has higher plate dissipation(remember
> the 30S-1 mod with the high screen voltage?).
>
Isn't that quite a project? IIRC the 4CX-1000 uses a bayonet socket while
the 4CX-1500 uses a more conventional socket.
If the Chinese are building lots of tubes are't they building the 3CX and
4CX 800's?
Maybe I should consider rebuilding my 2002A, but it doesn't have a heavy
enough PS for the 4CX1500 let alone the screen supply. <:-))
73
Roger (K8RI)
> Bob W6TR
> ----- Original Message -----
> From: "Dennis W0JX" <w0jx@yahoo.com>
> To: "Amplifiers" <amps@contesting.com>
> Sent: Tuesday, May 20, 2008 9:42 AM
> Subject: Re: [Amps] New Amps at Dayton
>
>
>
>> The only thing that I saw at Dayton worth noting is a change in the
>> current Alpha 8100.
>>
>> The finals have been replaced with TWO 4CX1000A's instead of the
>> 4CX800A7's and the amp has been relabeled either an Alpha 8200 0r
>> 8400 (sorry I tossed the literature and can't remember the exact number).
>>
>> Anyway, this should be considered a warning to any amp owner who has
>> an Alpha 91, 99 or 8100, QRO 2500, or ACOM 1000 and 2000A. Alpha said
>> the supply of GU-74B's is drying up quickly and they made the switch
>> to ensure availability.
>>
>> Incidentally, the 4CX1000A's used are NOT Eimac but made by Penta in
>> China.
>>
>> 73, Dennis W0JX/8
>>
>>
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>>
>
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