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Re: [Amps] sb-220 questions

To: amps <amps@contesting.com>
Subject: Re: [Amps] sb-220 questions
From: Dan Sawyer <dansawyer@earthlink.net>
Date: Sat, 21 Feb 2004 16:23:35 -0800
List-post: <mailto:amps@contesting.com>
All, follow-up;

The 100 ma idle plate current is on low power. It is 140 ma on high power; so the "idle" state seems ok.

However the amp defiantly will not put out full power. Grid current 'hockey sticks" high at about 25 watts drive putting out about 500 watts and with no additional output power.

1. 80 and 40 meters do not seem to tune well. The 'tune' cap is near fully engaged. These bands "hockey stick" grid current at about 400 watts out on 20 watts drive. How can I test to determine is they are properly tuned with the 'tune' control at a maximum??

2. 20 and 15 meters tune up nicely and put out about 600 watts before they hockey stick grid current at about 25 watts drive.

3. 10 meters is weak, it only puts out about 200 watts.

Is this simply really weak tubes or is there something else wrong??

Thanks,
Dan

Steven Grant, W4IIV wrote:

should have 150 ma with no drive...tho 100 is ok i reccon...may be a tad low
steven W4IIV
*/Dan Sawyer <dansawyer@earthlink.net>/* wrote:


All,

I just picked up an sb-220 and it is not behaving 'properly'.

    It draws about 100 ma of plate current with no input, just the relay
    closed. Is this normal??

    It behaves predictably up to about 20 watts of input. It develops
    about
    20 to 1 gain from 1 watt in to about 20 watts in. At about 20 watts
    input there does not appear to be any additional power out and both
    plate and grid current rise sharply. Is this weak tubes or
    something else??

    Thanks,
    Dan



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STEVEN GRANT W4IIV
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