Re: [Amps] [Bulk] Re: 572B - News?

["Carl" <km1h@jeremy.qozzy.com>]

I disagree about the Svetlana 572B and repeated underated problems led to 
its being discontinued. Perhaps they rated it at some imaginary IVS 160W 
instead of  ICAS commercial use. All used a ceramic base AFIK.
Svetlana also fraudently changed the GU-74B from a 600W PD to 800W when they 
scrubbed and relabled it as the 4CX800A.
Of course any 572B will be loafing in a 30L1 as it is still running as a 
811A. Its a good swap in the Ameritron AL-811's as Amertron did themselves 
as the AL-811HD.
Ive had a pair of Svetlanas in an AM modulator running fine at 1600V for 
over 20 years as 811A's; and another pair really loafing at 900V in a Clegg 
Zeus.
A single 813 1954 QST cover TX will be getting another pair once I finish 
the restoration. I have maybe 8 remaining from a bulk buy near the end.
The T-160L was a Taylor designation that was never produced in any quantity 
and intended as an AM modulator and sold as a 572A by UE and 572B by Cetron 
with the T-160L marking also included for several years.
UE then built the 572B for Cetron who couldnt keep up with orders; UE = 
round top, Cetron = shouldered top. The reverse was also true.  All other US 
branded 572B's were made by the two actual manufacturers.
The 160W was always an ICAS rating.

Carl
KM1H



----- Original Message ----- 
From: "Dave" <d.gow@frontier.com>
To: "'Al Kozakiewicz'" <akozak@hourglass.com>; <amps@contesting.com>
Sent: Friday, November 07, 2014 2:24 PM
Subject: Re: [Amps] [Bulk] Re: 572B - News?


> The service bulletin was in the bias system for the FL-2100B.   Improper
> bias triggered instability.  There were not RF related changes.The FL-200Z
> has a different bias system but I don't remember if it fixed the problem.
> The problem does not exist in the 30L1 or the SB-200 .All the details are 
> on
> the Web.  I Svetlana's plate dissipation rating is 160 watts, just like 
> the
> 572B.  Yes, the plates are smaller but they are also thicker and are made 
> of
> graphite like the original T160 (original nomenclature for what became the
> 572B.  I have a set of original ceramic base 572B in my 30L1 and they have
> worked perfectly for over 5 years of daily use and the amplifier is stable
> on all bands.  I wish I had bought a spare set back when they were current
> production.
>
> Dave
> W7VM
>
>
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Al 
> Kozakiewicz
> Sent: Friday, November 07, 2014 10:56 AM
> To: amps@contesting.com
> Subject: [Bulk] Re: [Amps] 572B - News?
>
> Plus, if I recall, there was a service bulletin on the 2100 (not sure it 
> it
> applied to the Z variant) regarding the use of the Svetlana tubes.  The 
> amp
> needed a modification (probably to the parasitic suppression?) to use that
> tube.
>
> Al
> AB2ZY
> ________________________________________
> From: Amps <amps-bounces@contesting.com> on behalf of Carl
> <km1h@jeremy.qozzy.com>
> Sent: Friday, November 7, 2014 1:03 PM
> To: David Harmon; 'Marcelo Cabral'; amps@contesting.com
> Subject: Re: [Amps] 572B - News?
>
> The Svetlana works OK but has a smaller anode and less dissipation. They
> havent been made in several years now.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "David Harmon" <k6xyz@sbcglobal.net>
> To: "'Marcelo Cabral'" <py1kr.marcelo@gmail.com>; <amps@contesting.com>
> Sent: Friday, November 07, 2014 12:25 PM
> Subject: Re: [Amps] 572B - News?
>
>
> > Marcelo.....
> > Try to find some 572-B made by Svetlana.......they are much better
> > quality.
> > I have had several sets of them and I prefer them over the Chinese
> > mfgd tubes.
> >
> >
> > 73
> >
> > David Harmon
> > K6XYZ
> > Sperry, OK
> >
> > -----Original Message-----
> > From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Marcelo
> > Cabral
> > Sent: Friday, November 7, 2014 11:18 AM
> > To: amps@contesting.com
> > Subject: Re: [Amps] 572B - News?
> >
> > Hi, Carl!
> >
> > Good news at the end!
> > Sincerely, I will try a MP pair of these new tubes after January, but
> > I haven't big expectations about their reliability.
> > But, if them survive at least one year, I must be finished the others
> > projects and be able for start this mod for GI7B. For today, I'll buy
> > some GI7B's from UR4LL, must be useful in a near future.
> > Thanks everyone, hope to meet everybody in CQWW CW soon.
> >
> > Marcelo - PY1KR
> >
> > -----Original Message-----
> > From: Carl [mailto:km1h@jeremy.qozzy.com]
> > Sent: sexta-feira, 7 de novembro de 2014 14:52
> > To: Marcelo Cabral; amps@contesting.com
> > Subject: Re: [Amps] 572B - News?
> >
> > RF Parts will be taking new 572B orders in Jan 2015, Id rather wait
> > than hack up a perfectly good amp for an inferior tube.
> > http://www.rfparts.com/tubes/tubes-572b.html
> >
> > Carl
> > KM1H
> >
> >
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