They probebly have to drive them too hard to hard so the IMD is poor.
I had a pair and tried to build an amp with them. I could not get it to put
out 1500 watts and stay within the specifications that I had for the tubes.
I put in a pair of 3CX800s and away I went! You can see the amp @....
http://home.centurytel.net/w7ry/Jims%20Amplifier%20Page.htm
73
Jim W7RY
On Mon, Feb 15, 2010 at 6:13 PM, Michael Tope <W4EF@dellroy.com> wrote:
> Is there a reliable supplier of NOS GU74B/4CX800A's? I have an Alpha 91B
> and was thinking that I should pick-up some spare tubes for it before
> the NOS pool dries up completely. I see that UR4LL is advertising them
> for $100 each. That seems too good to be true. Is he legit?
>
> BTW, I agree that the 4CX800A isn't a terribly clean tube for SSB
> service. All the commercially available amps I've seen with this tube
> (including the Alpha91B) have mediocre IMD specs.
>
> Thanks,
>
> Mike W4EF...................
>
>
> On 2/15/2010 5:20 PM, Carl wrote:
> > ----- Original Message -----
> > From: "Cecil Acuff"<chacuff@cableone.net>
> > To:<gdaught6@stanford.edu>;<amps@contesting.com>
> > Sent: Monday, February 15, 2010 7:57 PM
> > Subject: Re: [Amps] 4cx800a
> >
> >
> >
> >> ----- Original Message -----
> >> From:<gdaught6@stanford.edu>
> >>
> >>
> >>> Since publication, the 4CX1600B is unobtanium. The
> >>> 4CX800A may have the same status. There are a few (fewer and fewer!)
> >>> GU-74B's
> >>> around, and prices are climbing.
> >>>
> >>
> -------------------------------------cut-----------------------------------------------
> >>
> >> Interesting about the 4CX800A...it's potential availability and most of
> >> all
> >> the bad reports of it's performance. (IMD etc.)
> >>
> >> I had considered the purchase of an Acom 1000 a while back. It gets
> >> nothing
> >> but rave reviews as one of the best ever amps and the Acom 2000A DX
> Dream
> >> machine that it out of reach for folks like me.
> >>
> >> Makes one wonder what to believe in...
> >>
> >> Cecil
> >> K5DL
> >>
> > The average amp owner could give a hoot about anyone else on the band. He
> > probably figures IMD is a government agency. As I said earlier the tube
> isnt
> > bad when its boiling water on the cover of the amp.
> >
> > Even 811 MFJ amps get rave reviews from those who dont know any better.
> >
> > Carl
> > KM1H
> >
>
>
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>
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