[Amps] Alpha 76a
km1h at jeremy.mv.com
Mon Sep 12 17:00:53 PDT 2011
----- Original Message -----
From: "Patrick Barthelow" <apolloeme at live.com>
To: <mikea at mikea.ath.cx>; <amps at contesting.com>
Sent: Monday, September 12, 2011 3:00 PM
Subject: Re: [Amps] Alpha 76a
> I received a 76A about 6 months ago, as a gift from a OOM who I helped a
> lot when he was active. A 3 holer, that had been stored for some time, I
> "gettered" it, slowly, bringing it back to life, without incident. On ALL
> amps I have run, I am hyper aware and observant of grid current, in the
> interest of long life, and note that Bob Wolbert has published a grid
> overcurrent trip circuit for the Alpha, that might be wise to install.
> While getting used to normal tuning dynamics of my New/old stock Alpha, I
> was startled somewhat at the grid current dynamics. At how quickly the
> Ig goes from very low values to very high values with small adjustments of
> input power, and tune and load controls, even with a good amount of
> loading. Perhaps this is "normal" for a 3 holer '76A but maybe it is
> saying something about one or more tubes. Other than that Ig
> sensitivity, the Alpha is the "AC Cobra 427 " of amps, IMHO. and with
> winter coming up, if I operate QRO with it, I will not
> heed a shack heater, or a fire to cook marshmallows.
> Best Regards,
> Pat Barthelow AA6EG
Well thats a good analogy but like any fast revving high winder when they
come apart it aint purty. I wouldnt put it anywhere near the 427 Cobra but
more like a finely tuned Boss 302 or Camaro first generation Z/28; a lot of
fire in a small package.
Now if you want a 427 performance get an LK-800A or C with the 3CPX800A7's
and the 3000V PS upgrade.
That amp can do nasty things to a 5KW slug with 120-150W of drive.
>> Date: Mon, 12 Sep 2011 13:31:22 -0500
>> From: mikea at mikea.ath.cx
>> To: amps at contesting.com
>> Subject: Re: [Amps] Alpha 76a
>> On Mon, Sep 12, 2011 at 11:20:33AM -0700, ROBERT HARMON wrote:
>> > Charles,
>> > I agree 100%. The Alpha 76PAC is one of the best amps ever made, a real
>> > workhorse. Like a Timex watch, "takes a licking and keeps on ticking" ,
>> > with one caveat, as you indicated, watch the grid current.
>> > I run mine hard all the time (and keep a watchful eye on the grid
>> > current)
>> > Remember the "brick on the key" advertisements for these amps ? My
>> > favorite is the ad used in 1981 which shows the usual heading of " Key
>> > Down, How Long ?" and instead of the normally used brick on the key
>> > there
>> > is a skeleton sitting there with his hand on the key. Now thats a good
>> > amp ! hihihi
>> Erm ... As long as he's not wearing a nametag that reads "Ross Hull".
>> Mike Andrews, W5EGO
>> mikea at mikea.ath.cx
>> Tired old sysadmin
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