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[AMPS] Re: Amps Digest V1 #321

To: <amps@contesting.com>
Subject: [AMPS] Re: Amps Digest V1 #321
From: c-hawley@uiuc.edu (Chuck (Jack) Hawley)
Date: Wed, 24 Dec 1997 08:34:31 -0600

Amps Digest wrote:

To: <amps@contesting.com>
> Date: Tue, 23 Dec 1997 20:25:11 -0800
> From: Joe Humet <jhumet@mhv.net>
> Subject: [AMPS] Drake L7
>
> I'm looking into buying a Drake L7 amp.
> Can anyone give their input both PRO & CON.
> 73 & Tnx
> Happy Holidays
> Joe  K2DS
>

I have an L7 and I think it is a good amp overall. I had an L4B and heard the
criticisms about the L7 being not made as well. It is made differently but 
doesn't
suffer on account of it. The cooling is the most commented on which is 
different in
that there are no chimneys. The air is drawn from vents in the bottom cover 
under
the tube sockets, into the rf deck and thru the fan and out the back. The fan 
runs
at reduced speed until a mechanical sensor in the air flow shorts out a 
resistor and
applies full voltage to the fan. On my amp, I think this switch point is a 
little
conservative, but at least you don't have to listen to the fan when you don't 
talk
(or cw) much. My L4B got really hot, chimneys or not. The solder fell out of the
tube pins once on the L4B. Eimac would fix them, but I think it wouldn't have
happened if the socket pins were tighter. Probably the same goes for the L7. 
Inside,
the amp is robust, never arc'ed anything over, etc. The bandswitch looks 
somewhat
difficult to get to but it never has needed any attention. I looked at this 
thinking
that I would put 10M on it, but decided that I'd need more incentive than I 
had. I
think there is a screw (stop) that you move and add a couple of caps to the new 
pos
on the input ckt (drawn in the schematic on my copy as 'export'). 160M was more
important to me than 10M anyway. It does about 1300 watts on 80M.
As far as cons go, I miss being able to see the tubes glow........
--
Charles (Jack) Hawley
Chuck....Ham Radio KE9UW
AKA "Jack" BMW Motorcycles, MOA #224 K100RS
Wife rides...Viki, MOA #18120 K100RS
President IBMWR
c-hawley@uiuc.edu
Sr. Research Engineer Emeritus
University of Illinois, Urbana-Champaign



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