[Amps] New Amps at Dayton

Tue May 20 19:39:27 EDT 2008

No, I don't think so. I homebrewed one about 30 yars ago.Back then free 
pulls were easy to come by from one of the other local high VHF channels.(we 
were low VHF and didn't use them) Was a great amp/tube, but it needed lots 
of protection to keep it safe and about 1500 to 1600 watts was all you dared 
squeeze out of it. I soon decided the the warm up time and complexity wasn't 
worth it, so I tore it down. I spent lots of hours building it up, but it 
didn't take long to rip it apart. My only regret was I didn't take any 
pictures of it before demolition.. Done right the bias and screen supplies 
need to be regulated and the screen supply interlocked to the HV..There 
certainly were then and are now better ways to go. I can't see why anybody 
would go that way now. The sockets and bypass rings weren't cheap then, can 
only imagine about now.
Chuck
W6RD
----- Original Message ----- 
From: "Bob Maser" <bmaser at tampabay.rr.com>
To: "Roger (K8RI)" <sub1 at rogerhalstead.com>; "Amps" <amps at contesting.com>
Sent: Tuesday, May 20, 2008 4:13 PM
Subject: Re: [Amps] New Amps at Dayton


> The same socket is used for the 4CX1000A and the 4CX1500B(p/n SK800B). 
> The
> 4CX1500A uses a different socket(SK831). Increasing the screen voltage 
> does
> wonders for output.  That is how owners of the 30S1 were able to improve
> performance.
>
> Bob
> ----- Original Message ----- 
> From: "Roger (K8RI)" <sub1 at rogerhalstead.com>
> To: "Amps" <amps at contesting.com>
> Sent: Tuesday, May 20, 2008 6:03 PM
> 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 at yahoo.com>
>>> To: "Amplifiers" <amps at 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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