[Amps] Alpha SX/DX Conversion

[Charles Harpole]

Friends have the factory stock two tube version and they have SO 239.  I like the bragging rights, but actually the two tube version is for the foul mouthed guys on uper 75m or for a guy feeding a power divider to shoot RF to two sets of yagis pointed two different directions at the same time. Watch out using all older amps on 12 meters, something about overheating the tank or something.  73,

Charles Harpole
k4vud at hotmail.com   
 > From: w9ac at arrl.net
> To: amps at contesting.com
> Date: Tue, 4 Sep 2012 21:20:24 -0400
> Subject: Re: [Amps] Alpha &&DX Conversion
> 
> Larry,
> 
> You've gotta' really want to add the 2nd tube for a good reason.  The 77Dx 
> is already capable of 2500w+ output power.   Apart from bragging rights, I'm 
> just not sure why anyone wants or needs the added power.  Adding the 2nd 
> tube to the 77Dx really requires a change to an outboard transformer, larger 
> fuse holders, and arguably, an upgrade of the SO-239 output connector. 
> The transformer and 25uF filter cap are marginal for one tube.
> 
> I only see problems with the 2nd tube addition that cannot be overcome by 
> any benefit.  Adding the 2nd tube also unnecessarily adds to ongoing cost 
> and more difficulty in troubleshooting.
> 
> My 77Dx will never be converted.  In fact, the spare second filament line 
> (to heat the 2nd 8877), is now used to balance the filament through a choke.
> 
> Paul, W9AC
> 
> ----- Original Message ----- 
> From: "Larry P. Greenberg" <wa9mag at ameritech.net>
> To: <amps at contesting.com>
> Sent: Tuesday, September 04, 2012 9:02 PM
> Subject: [Amps] Alpha &&DX Conversion
> 
> 
> >I have recently picked up an Alpha 77DX and wonder what the general 
> >consensus is about adding a second tube.  According to the N4UQ website, my 
> >amp qualifies.  However, the power transformer seems a little skimpy to 
> >supply current to two tubes.  Also, does this amplifier work on the WARC 
> >bands.  Any pros and cons would be appreciated.
> >
> > Larry, WA9MAG
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