[Amps] 572b

[Jeff Blaine]

I have used about 8 of the Chinese 572 specifically for torture testing in 
RTTY service and I can say without qualification that the plate dissipation 
limit (IIRC 160w) is not something which will keep the tube in long service. 
But whipping the hell out of these tubes in AM/FM/RTTY service with all the 
guns blazing is not the common application.

I would expect the current breed to give long SSB service as long as tuning 
is done properly and kept to a minimum.  For CW, almost as well.  From 
there, it goes down hill fast.

Comparing them with prior generations makes no sense because there are 
virtually zero NOS old tubes remaining.  You either buy the Chinese (through 
some direct or distribution method) - and that is the only source available 
and take what service life you can get.  Or you can flip to another tube 
type at some considerable amount of work and expense.

73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-----Original Message----- 
From: L L bahr
Sent: Thursday, May 02, 2013 5:00 PM
To: amps at contesting.com
Subject: Re: [Amps] 572b

If quality control is so poor, how do you test for longevity or robustness? 
Just checking the emission when new may have nothing to do with longevity. 
I'd like to know how well a Chinese 572B will hold up compared to a Cetron 
572B.  I wonder what short cuts the manufacturer has taken in production 
when many new ones go out the door with poor emission. What else is wrong 
with them?   Maybe it's time for these amplifiers to be retrofitted with 
other type tubes.

Lee, w0vt

----- Original Message -----
There's no doubt that the manufacturer is the problem, but since they are 
the only one making them  and most Ham's just need a few, a reputable 
distributer is very important in the supply chain.  He tests them before 
selling them to be confident that they worked when they left his facility, 
that is one of the reasons he is considered reputable.  It costs more, but 
he must becompensated for his time.  A reputable dealer is paramount in 
buying a tube you know has a decent chance of being good, andis the one 
thing you can do anything about-choose who you buy from !! Cheers,  Matt 
73AD7XN
_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps at contesting.com
http://lists.contesting.com/mailman/listinfo/amps