Hello Joel:
From what you describe, it seems that your Centaur may have an internal
problem causing the the same tube to fail. A parasite comes to mind.
What is the Ep with the Centaur. I would estimate 1500 to 1800 VDC, which
811's are very happy with. 572's are at home with 2200 to 2500 VDC (if my
memory serves me right). Just plunking in 572's that will operate at a lower
Ep may cause the tubes to have a bias problem which may cause a lower power
output as compared to the 811's. This problem showed up years ago when guy's
were switching out the 811's for 572's in their 30L1's.
The above is IMHO; & YMMV etc, etc.
Wishing you and yours had a great Christmas.
Later
Bill_Harris
> I don't agree with that, Bill.
>
> I bought my Centaur to use as a portable contest amp.
> At the time I was usually running multi-single class, so we always had
> numerous hams working with the equipment. Often there were inexperienced
> guys learning to contest with us.
>
> I sold the Centaur after two years because the guys kept blowing the 811A's.
> It was always only one tube that blew, but I kept replacing them in matched
> sets. Got to be too expensive for me, so I sold the amp.
>
> Although I haven't tried, I'm sure the amp will be more robust with 572B's
> than it was with 811's. Yes, you spend more money "once" but then you have
> stability.
>
> I've often regretted selling it. I don't work the multi-single anymore and
> the Centaur would be a good portable and backup amp for me (as single
> operator), especially with 572B's.
>
> QUESTION: Has anybody had any negative experience using the 572B's?
>
> 73
> Rick
>
> -----Original Message-----
> From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
> On Behalf Of Bill_Harris
> Sent: Saturday, December 25, 2004 8:35 PM
> To: tentec@contesting.com
> Subject: Re: [TenTec] Centaur
>
> Joel, you better off with the 811's. That's what the rig was designed for.
> Putting in 572"s will not net you enough additional power to be noticed.
> IMD products are reported to be higher as well. Your money ahead staying
> wit the 811's.
>
> carry on
>
> Bill Harris
>
>
> > Ron,
> >
> > Great question, and I will be watching the answers closely too. I fried
> > an 811A in my Centaur the other day and can see the bottom of the
> > spare bin very clearly now!
> >
> > The big question is, when I toss my last spare 811A, should I go with
> > 572Bs or stick with 811As? The 572Bs that everyone liked from Svetlana
> > don't seem to be available any more (source?) and I wonder if the Taylor
> > 572Bs offered by RF Parts will be as good. Anyone have good luck with
> > them in a Centaur?
> >
> > Thanks for everyone's help!
> >
> > 73 & Merry Chistmas,
> > Joel Hallas, W1ZR
> >
> > Ron Feutz wrote:
> >
> > > TT'ers,
> > >
> > > I cooked a tube or tubes in my Centaur while tuning up. Any
> > > suggestions on the best place to get replacements, and the best
> > > replacements to get? For the price I suppose it makes sense to get a
> > > matched trio.
> > >
> > > I see RF parts has quite a selection and the prices look reasonable.
> > >
> > > 73,
> > >
> > > Ron KK9K
> > >
> > >
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> > >
> >
> >
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