[Amps] Considering an Alpha 76PA

jeremy-ca km1h at jeremy.mv.com
Wed Oct 31 17:08:52 EST 2007


I dont know of any low drive mod for the 76CA/PA Gary. You may be thinking 
of the MLA-2500 and that mod was guaranteed to fry tubes.
I dont remember any factory QSK option either, just an open frame relay 
similar to Heath, Dentron, etc.

That Johnson TR switch is a TVI generator, it generates all sorts of 
switching harmonics. Do you want to sell it? I could use it on my Viking I - 
HQ129X combo which will be living on 160-40M.

Carl
KM1H


----- Original Message ----- 
From: "Gary Smith" <Gary at doctorgary.net>
To: <amps at contesting.com>
Sent: Wednesday, October 31, 2007 5:08 PM
Subject: Re: [Amps] Considering an Alpha 76PA


> Carl,
>
> Is that the low drive mod I've read about?
>
> I'm perfectly happy with 1200 watts out, especially if I don't need
> much drive to get that. Pushing to get the max out just doesn't make
> it worth the wear & tear to me.
>
> Is the three hole 76 QSK or does it have a standard relay?
>
> Years ago I made a QSK for my old heath 220 using Rich Measures
> circuit. It worked very well but I no longer have any of those vacum
> & reed relays nor optoisolators.
>
> I do have my dad's old Johnson t/r switch but don't see how I can use
> that with a corsair & amp for qsk. I need to think about that a
> bit...
>
> Gary
> ka1j
>
>> No, it has 10 470 Ohm 2W carbons in parallel.
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message ----- 
>> From: "Mike, K6BR" <noddy1211 at sbcglobal.net>
>> To: <amps at contesting.com>
>> Sent: Wednesday, October 31, 2007 3:00 PM
>> Subject: Re: [Amps] Considering an Alpha 76PA
>>
>>
>> > Does it have a tuned input?
>> >
>> > Mike
>> >
>> > -----Original Message-----
>> >
>> >
>> > The nice thing about the 3 holer is that 100W of drive is split 3
>> > ways and doesnt overdrive. Keep that grid current down, limit output
>> > to 1200-1300W and they will have a long happy life. Problems start
>> > when owners try and get
>> >
>> > 1800W out.
>> >
>> > Carl
>> > KM1H
>> >
>> >
>> > ----- Original Message ----- 
>> > From: "Roger" <sub1 at rogerhalstead.com>
>> > To: <Gary at doctorgary.net>; <amps at contesting.com>
>> > Sent: Wednesday, October 31, 2007 2:28 PM
>> > Subject: Re: [Amps] Considering an Alpha 76PA
>> >
>> >
>> >>
>> >>
>> >>
>> >>>I own(ed) an Alpha 77SX serial 2931 & it went to ETO for
>> >>> repair after an internal arc-over. They lost track of it when they
>> >>> relocated & I'm still out an amp or compensation. Someone,
>> >>> somewhere has my 77SX that ETO/Alpha should have returned to me
>> >>> but never was.
>> >>>
>> >>> I need another amp and am considering an Alpha 76PA as I remember
>> >>> using one at field day and it seemed like a fairly straight
>> >>> forward amplifier. I'll be using it with a corsair II.
>> >>>
>> >>> I have no idea what ta 76pa is selling for but I know the tubes
>> >>> are hugely overpriced to replace. Anyone know of one of these amps
>> >>> in decent condition?
>> >>
>> >> The 76A is a nice amp. The only real considerations are watching
>> >> the grid current on tune up and of  course the price of the tubes.
>> >> There are two versions with the difference being 2 or 3 tubes.
>> >> There's a pair of 8874s on e-bay at present with the current
>> >> bidding over $700 for the pai.   I've seen very nice ones go for
>> >> $750 USD and some scruffy ones that needed the panel replaced (bad
>> >> paint) for over $1500.  Typically the prices do vary over the range
>> >> listed with nice ones covering the whole range, but I'd say the
>> >> nice two tube tend toward $1000 to $1200 with the three tube units
>> >> going for a bit more.
>> >>
>> >> I've been using the two tube version for some years now and it's a
>> >> great conventional amp that has very little cooling noise. Others
>> >> may have a different opinion.
>> >>
>> >> BTW, it's warm enough my BIG cat likes to sleep on it so I have to
>> >> look to see where he is before firing up.
>> >>
>> >> 73
>> >>
>> >> Roger (K8RI)
>> >>>
>> >>> Any caveats with this amp I should consider?
>> >>>
>> >>> Thanks
>> >>>
>> >>> 73,
>> >>>
>> >>> Gary
>> >>> ka1j
>> >>>
>> >>> offlist is fine if you know of one that's available.
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