[Amps] 4CX1500B's -- worth using?

[Peter Voelpel]

And the 5CX1500A is used in mine, nice tube as well

73
Peter, DJ7WW 

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of David C. Hallam
Sent: Donnerstag, 21. Juni 2012 00:21
To: amps at contesting.com
Subject: Re: [Amps] 4CX1500B's -- worth using?

That's why my HB linear has a 4CX1500A.

David
KW4DH

On 6/20/2012 5:57 PM, Carl wrote:
> The 4CX1500B is a direct replacement in a Collins 30S1 without any 
> changes OR the increased screen voltage mod can be done for more 
> power. Idle current bias needs a tweak and a heat extractor is a good 
> idea if its used heavy duty. The nominal filament current is 1A more.
>
> A friend had a pair on 2M that would do over 3000W for EME and contests.
>
> Not to be confused with a 4CX1500A which has a real grid and can be 
> well abused without damage.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "David Kirkby" <david.kirkby at onetel.net>
> To: <dhallam at knology.net>
> Cc: "Vic K2VCO" <k2vco.vic at gmail.com>; "Amps reflector"
> <amps at contesting.com>
> Sent: Wednesday, June 20, 2012 3:52 PM
> Subject: Re: [Amps] 4CX1500B's -- worth using?
>
>
> On 20 June 2012 20:37, David C. Hallam <dhallam at knology.net> wrote:
>> That's what I was trying to imply. The writer of the original post on 
>> the matter seemed to have the idea that a 4CX1500B was not as good as 
>> a 4CX1000A.
>>
>> David
>> KW4DH
> I don't think they are direct replacements. IIRC the screen voltage is 
> different, though perhaps not so drastically so that your could not 
> use the same screen voltage. The filament of the 4CX1500B needs more 
> current than that of the 4CX1000A if I recall correctly.  The 4CX1500B 
> will produce a cleaner signal.
>
> I built a twin 4CX1000A amp for 2m, and never did get it working very 
> well. I recall speaking to John G4FRX (now GW4FRX) and he said the 
> 4CX1000A caused more problems for hams than any other tube. I don't 
> think its considered one of Eimacs best tubes. The 4CX1500B is 
> certainly superior.
>
> As I say, there are date sheets on my web site.
>
> dave
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