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Re: [Amps] New 4-1000 Tubes ?

To: "Roger \(K8RI\)" <k8ri@rogerhalstead.com>, <amps@contesting.com>
Subject: Re: [Amps] New 4-1000 Tubes ?
From: "Carl" <km1h@jeremy.mv.com>
Date: Wed, 9 Jan 2013 13:09:07 -0500
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Ive only used them at audio Roger but I suspect that in GG they will have IMD in the mid 30's if not beat on as do the Europeans who sound like CBers. That tube has plenty of reserve emission for clean PEP peaks so use it properly. Make believe it is 4-250/4-400 and put some air on them as heat has always been a life killer even if the glass can take it. Im using a SB-220 fan at reduced speed.

Carl


----- Original Message ----- From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
To: <amps@contesting.com>
Sent: Monday, January 07, 2013 10:25 AM
Subject: Re: [Amps] New 4-1000 Tubes ?


On 1/7/2013 9:32 AM, Hsu wrote:
Why few amp manufacturer use GU-81M,?it is cheap and rugged.


Probably because the manufacturers data sheet de-rates the GU-81 rapidly as you go up in frequency. Few home brewers OTOH run them within their ratings. According to builders in Europe they run 3 KW out of a pair with no forced air cooling. Apparently this is a tube that can really be abused and still hold up. I have no idea as to the IM when used like this, but Carl might.

A pair do make a nice looking amp that is also quiet. I've been playing with the idea of a pair on 160 through 40 or even single band.

73 Roger (K8RI)



Dr Alex Gavva   QRO Parts Site: http://www.ur4ll.net
UR4LL
KO70XG          mailto:ur4ll@ur4ll.net

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