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Re: [Amps] Drake amplifier

To: <>, <>,<>
Subject: Re: [Amps] Drake amplifier
From: "jeremy-ca" <>
Date: Mon, 23 Jul 2007 14:55:45 -0400
List-post: <>
1KW input on CW, 2KW PEP on SSB was the FCC reg back then. For that reason 
many amps of that era had a CW/SSB plate voltage switch. Many left it in the 
SSB position irregardless of the mode (;  No sense in throwing away 3dB in a 


----- Original Message ----- 
From: <>
To: <>; <>
Sent: Monday, July 23, 2007 12:33 PM
Subject: Re: [Amps] Drake amplifier

> 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
> exactly.
> 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.
> Thanks
> 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 
> runs
> 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 
> 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 a
> 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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