[NJARC] 572B tubes

[manualman]

Not really that scarce since they were used in thousands of Heathkit
SB-200's, SB-201's, Yaesu amps, Dentron amps, and a number of other amps.
I see these tubes pop up at flea markets all the time. Plate dissipation
of the 811's is less then the 572B's.  572B's are drop-in replacements
for 811's but some circuit analysis would have to be done to go from
572B's to 811's. If the tubes are mounted vertically, any variety of
572B's should work fine. Chinese 572B's, or was it Russian 572B's, had a
history of filament sag when mounted horizontally. 

Pete, wa2cwa
 
On Thu, 02 Jul 2009 08:30:29 -0400 pmalvasi at aol.com writes:
> Just remember 
> Reply = Poster
> Reply All = Everyone
> 
> _________________________________________________________
> I agree with Joe re the 572;s - fairly pricey and scare but 811's 
> should work in their place altho I think there is a small 
> modification needed... 
> 
> 
> -----Original Message-----
> From: joseph cro <n3ibx at verizon.net>
> To: Scott Roberts <ng19delta at yahoo.com>; NJARC Radio Club 
> <njarc at mailman.qth.net>
> Sent: Thu, Jul 2, 2009 6:59 am
> Subject: Re: [NJARC] 572B tubes
> 
> 
> 
> Just remember 
> Reply = Poster
> Reply All = Everyone
> 
> _________________________________________________________
> Scott,
>         I have a pair of regular 866A's you're welcome to. They're 
> not the 
> AX variety as manufactured by GE, but they should do the job just 
> the same. 
> Regarding 572B's, they're pretty hard to come by used since they 
> were 
> designed specifically as a "Amateur Radio" type of tube, not used in 
> 
> commercial applications. RF Parts in Ca. sells their Chinese made 
> "Taylor" 
> 572B's for around $50 or so each. I think your best bet would be to 
> contact 
> them if you don't get any responses. You could also try QRZ.com in 
> their 
> wanted column. Ditto with "Eham.net". You may just get lucky and 
> find 
> someone who has a used pair to sell you at a reasonable price.
> 
> Best Regards,
>                     Joe Cro N3IBX