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Re: [Amps] New Amps at Dayton

To: <amps@contesting.com>
Subject: Re: [Amps] New Amps at Dayton
From: "Peter Voelpel" <df3kv@t-online.de>
Date: Wed, 21 May 2008 01:03:57 +0200
List-post: <amps@contesting.com">mailto:amps@contesting.com>
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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