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How to tune a tube amp.

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  #31  
Old 09-13-2009, 05:01 PM
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Default Am I tuning The Amp Wrong?


I key 5 watts from the exciter and tune the antenna with a tuner and get 1.1.
Then I key the exciter to 100 watts and check the swr again and it is 1.1. (exciter)
I tune the amp in cw with 50 watts on the cw position.
If I want to talk on 75 meters, I'll put the amp knob on 75 meters.
Then I key up the exciter and amp and watch the external/power meter.
I will first tune the plate knob until I see the highest signal on the meter.
Then I tune the load knob which is right under the plate load until the power is at the highest.

Now I'll look back at the amp and I am always under .4 on the plate amperes meter. The wattage on the amp meter is equal to the wattage on my external meter. I thought that if we get the highest wattage on the watt meter coming out of the amp by moving the knobs a little this way and a little the other way that the amp is tuned perfect. I have a 1500 watt amp and the external meter is reading this going out on the air. Am I turning it right? I can tune the amp real fast by keeping an eye on the watt meter.
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  #32  
Old 09-13-2009, 07:34 PM
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If you take care not to exceed the grid and plate currents (ought to be in the amplifier's manual), then "tuning for smoke" is basically the same as any other way of tuning. I think it's done that way, more often than other ways, by most amplifier users. The biggies are those limits!
Depending on the tube and particular amplifier design, they -might- be 'pushed' just a 'smiggin', but be very, very careful when you do. Almost 100% of the time it is NOT worth it. Those limits are there for a good reason. Change them at your own ri$k.
- 'Doc

PS - SWR doesn't change with the power level unless you exceed something's power handling ability. Then it changes very quickly .
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Old 09-13-2009, 10:44 PM
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Thanks for the infomation. If I do a quick glance, the limits are ok. I guess if I exceeded the amp specifications, then I would have trouble getting the highest peak on the external meter.
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Old 09-13-2009, 10:53 PM
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I don't think I'd worry about not getting a peak on a meter. I would worry about that peak not lasting very long because of the tube/amplifier quitting. As in letting the magic smoke out of it.
- 'Doc
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Old 10-03-2009, 10:20 PM
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Default never mind

...

Last edited by Slam Dunk; 10-07-2009 at 12:33 PM. Reason: .
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