[Amps] Alpha 78 with 8874 Triodes

Carl km1h at jeremy.mv.com
Wed Apr 23 16:55:24 EDT 2014


I have a 3 tube 76PA and when those give up there is plenty room for a pair 
of 3CX800A7's or the 3CPX version, only $400 ea from Alpha and good pulls 
about half that. Add a filament transformer and new red silicone rubber 
cimneys.
Lots of info via Google.

Meanwhile the 8874's will still do 1800W on a quick test with well under 
rated grid current; I run them at 1200W.

Carl
KM1H

----- Original Message ----- 
From: "Chuck Curran" <ccurran at wi.rr.com>
To: <amps at contesting.com>
Sent: Wednesday, April 23, 2014 3:48 PM
Subject: [Amps] Alpha 78 with 8874 Triodes


> Hello the Group:
>
>
>
> I am working on an Alpha 78 with three 8874 triodes, that are still in 
> good
> shape.  This particular amp was one that was built in late 1980, and the
> interior is in like new condition.  However, it was one of those that was
> built with the "SCRATCH PROOF" paint.  The catch is the paint broke down 
> on
> all of the Alpha amps that used it and is sticky like a coating of honey 
> was
> applied to all surfaces.
>
>
>
> I was able to obtain a brand new front panel and I stripped and repainted
> the sheet metal cover.  The cover turned out beautiful, just like the new
> front panel is, using a color coordinated paint my wife picked out, I am
> really bad at selecting complimentary colors!
>
>
>
> So here is the question.  If an owner would want to run the amps for a 
> long
> time, you have to consider tube availability.  The 8874/3CX400A7 is listed
> at $895 each at RF Parts, so I was wonder about re-tubing?
>
>
>
> I searched the archives and found a discussion/argument from February of
> 2002.  There a GI-7B was being discussed, but no results were ever posted.
> Now, 12 years later, have any on the list come across a tube that can be
> considered an available replacement with new sockets, for the three 8874's
> currently in place?
>
>
>
> I would greatly appreciate any advice available,  Thank You
>
>
>
> Chuck  W9KR
>
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