If you go to the Alpha website you can learn about the mods for the greater
output on the 76 models or they used to do it for a price. Most of the 76's
were modified for higher output power years ago although there probably are
a few still around as the amp was designed and marketed before the FCC
changed the rules on power but perfectly capable of putting out past the
legal limit at todays standards with a somewhat minor change to the input
circuitry.
Van, K7VS
I have two 76CA's that work well, look well and put out in excess of 1500
watts DC on CW and of course over 1500 watts PEP output (into a dummy load
of course) and I use them in "contest mode" running full legal limit on all
modes with no problems from CW thru RTTY.
----- Original Message -----
From: "jeremy-ca" <km1h@jeremy.mv.com>
To: <Gary@doctorgary.net>; <amps@contesting.com>
Sent: Wednesday, October 31, 2007 3:08 PM
Subject: Re: [Amps] Considering an Alpha 76PA
>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@doctorgary.net>
> To: <amps@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@sbcglobal.net>
>>> To: <amps@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@rogerhalstead.com>
>>> > To: <Gary@doctorgary.net>; <amps@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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>>> >>> Amps@contesting.com
>>> >>> http://lists.contesting.com/mailman/listinfo/amps
>>> >>
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>>> >>
>>> >
>>> > _______________________________________________
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>>> >
>>>
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>>
>>
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