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Re: [Amps] Multi-tube vs Single or Dual-tube amps?

To: amps@contesting.com
Subject: Re: [Amps] Multi-tube vs Single or Dual-tube amps?
From: Colin Lamb <k7fm@teleport.com>
Date: Mon, 19 Jan 2015 21:07:31 -0800
List-post: <amps@contesting.com">mailto:amps@contesting.com>

On 1/19/2015 8:25 PM, Fuqua, Bill L wrote:
    My preference is the 4-125A,
The 4-125A is interesting as an inexpensive tube. The data I have using the tube in grounded grid operation is from the $2.50 cost Single Sideband for the Radio Amateur, in the tube data page. Both grids grounded. it lists the following for a single tube:

Plate volts 3,000 (also lists 2,000 and 2,500, but power out is much lower)
Zero plate current 20 ma
Max sig plate current 115 ma
Max sig grid current  55 ma
Max sig screen current 30 ma
Input impedance 340 ohm
Driving power 16 watts
Useful power out 340 watts

The power out sounded a bit low - but then I recall that the 30L-1 uses 4 65 watt dissipation watt tubes which would be equal to about 2 x 4-125A tubes and that amp has about 650 watts out. But 700 watts is nothing to sneeze at.

73,  Colin  K7FM


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