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High Power Tubes [message #8192]

Tue, 25 May 2004 02:25

Wayne Parham
Messages: 18676
Registered: January 2001

Illuminati (33rd Degree)

Ever seen one of these transmitter tubes?

I found this link to Econco in one of the Google ads. Pretty interesting. Look at this military tube:

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Re: High Power Tubes [message #8195 is a reply to message #8192]

Wed, 26 May 2004 00:07

metasonix
Messages: 103
Registered: May 2009

Viscount

The upper photo is a TH347.
Often seen in VHF-TV transmitters I believe.
Lower looks like a water-cooled type for
industrial RF heating use, not military.

Econco's sales engineer is George Badger, who used
to be president of Svetlana USA. I have contact
info if you want to ask him questions about transmitting
tubes. He worked at EIMAC for 40 years, making him one of
the world's leading experts.

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Re: High Power Tubes [message #8197 is a reply to message #8195]

Wed, 26 May 2004 05:03

Wayne Parham
Messages: 18676
Registered: January 2001

Illuminati (33rd Degree)

Wow, small world! It was just interesting to me, without particular purpose. I saw the link on one of the Google ads at the bottom of a post, so I clicked on it and looked around. I remember seeing some people using transmitter tubes to build audio amps. High power SET amps, as I recall. Think of the transformers needed for that, huh?!!

Aside from financial concerns, what are some of the trade-offs you'd expect from using such a tube for high-power audio amps?

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Re: High Power Tubes [message #8202 is a reply to message #8197]

Thu, 27 May 2004 21:01

metasonix
Messages: 103
Registered: May 2009

Viscount

1. Most of them are medium-mu or high-mu triodes, or else
tetrodes with very high transconductance. This tends to
result in poor linearity. Tetrodes are usually ok if operated
push-pull.

2. We are talking about power supplies of 5-20 kV at
1 amp or more. Filaments need scores or hundreds of amps.
The power transformers end up weighing 200 lbs or more...

3. The output transformer will be huge, and VERY costly to make.

4. Large blowers for forced-air cooling, or else water connections
for water cooling (and big water bills), are mandatory.

Other than that, they make great audio tubes.

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