Pat,
Congratulations on acquiring the 76A, she will serve you well !
The grid overcurrent protection is a good idea. I am considering this for my
amp. Normally I keep
a close eye on the grid current but in the heat of battle during a contest
sometimes we lose our grip, hihi.
One thing you might consider if you haven't already is replacing the power
supply HV filter caps. They are more than ready
to be replaced if they are the originals.
73,
Bob
K6UJ
On Sep 12, 2011, at 12:00 PM, Patrick Barthelow wrote:
>
> 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 no
t
> heed a shack heater, or a fire to cook marshmallows.
>
> Best Regards,
> Pat Barthelow AA6EG
>
>
>
>> Date: Mon, 12 Sep 2011 13:31:22 -0500
>> From: mikea@mikea.ath.cx
>> To: amps@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@mikea.ath.cx
>> Tired old sysadmin
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>
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