Of all the ham gear I've owned and operated, the position of the ALC switch
on my L-4B for 'standby / operate' seems the most counter-intuitive function
to me - and one I screw up more times than I care to admit. From just a
human factors perspective, pushing the switch in would logically mean 'on'
or 'in-line', and pulling it out would mean 'off' or 'off-line'....when it
fact it's the other way around.
You can train dogs to do tricks....but I think I'm just too thick to learn
this one!
Thanks for the insight Garey.
73,
Greg Roecker/n4osj
Roswell, GA.
-----Original Message-----
From: Garey Barrell
Sent: Friday, January 13, 2012 10:01 AM
To: m coffey
Cc: drakelist@zerobeat.net
Subject: Re: [Drakelist] L4 vs. L4B
Mike -
Couple of things.
1. The L-4 never was sold with 4-400s. I assume you mean 3-400Zs.
2. Electrically, yes, you can replace the 3-400s with 3-500Zs. The problem
is that the '500s are a
little taller and won't fit in some of the chimneys Drake supplied. There
really isn't any reason
to replace 'good' 3-400s with 3-500s as long as you stay within the original
power specs. This is
about the limit of the power supply anyway. Yes, you can get close to
today's legal limit, if you
really need that one quarter of an S-Unit increase.
The main 'significant' difference between the two is that the "B" moved the
ALC level control from
the rear panel, and made it a 'push-pull' switch control to put the
amplifier in standby. Pushing
the knob "IN" takes the amplifier off line without turning it off. With the
L-4, you have to switch
the AC power off to bypass the amplifier. The 3-400/500Zs are 'instant on'
tubes so not an
operating problem, but you could argue about turning the amp on and off
multiple times.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
m coffey wrote:
Can anyone tell me the difference between the L4 and L4B ? Can one
replace the 4-400s with 3-500s? Mike
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