[Amps] Alpha &&DX Conversion

[Paul Christensen]

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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