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Re: [Amps] Drake amplifier

Subject: Re: [Amps] Drake amplifier
Date: Mon, 23 Jul 2007 12:33:14 EDT
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In a message dated 7/23/2007 12:21:44 P.M. Eastern Daylight Time, writes:

I have a  drake L7 amp.
How much power out do you typically get from a drake L4 or L7  amp? I have 95
watts drive and get just short of 1100 watts on 40  meters.

The amp's wattmeter and a bird wattmeter with a brand new slug  agree almost

This seems a little low or is that about all  that can be expected from the
3-500Z's. They run at 2450 volts on the  plates and 230 ma grid current.

Gary   K4FMX

Hi Gary, Yup, that is about right 110-1200 watts out with around 100 watts  
of drive.  If you have a look at an AL-82, it will do about 1600 watts out  
with 100 watts in.  The difference is in the fact that the Ameritron AL-82  
the anode at about 3600-3700 volts.  The extra plate voltage really  makes the 
3-500Z's play great.  The "HOT" set up for the Drake L4 or L7  would be to 
build up a better HV supply.  The Drake tank circuit can take  4KV no problem.  
But what you are seeing now is right on the money.   You have to remember that 
when the L4/L7 were made, the maximum power  permissible by the FCC was ONE 
KILOWATT DC INPUT.  That being so, the amp  companies did not run a pair of 
3-500's to their full potential so they got by  with wimpy power supplies.  Put 
good power supply on an L4 and it will  perform nicely.  Easy legal limit amp 
plus.  Oddly, the Drake RF deck  makes a great conversion to an 8877 and 
handles the 2KW easily.
73 Lou

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