[Amps] 572Bs

[Mitch Cox]

I have no way of knowing where the Chinese tubes I have experienced have come from. The brands that I have tried would include; Taylor, RF Parts select, Penta (X dealer), Jet Stream and the no name white box variety. I cannot recommend any of these to anyone for any reason. The quality control on the afore mentioned that I have purchased were terrible, never 2 the same length, had alignment problems with the grid and filament structures, lost the anode caps, were not glued to the base correctly and the ones that didn't flash over immediately or did actually light up and work, didn't last 6 months. If you can tell me what brand name they are selling in the US under I would be more than happy to purchase them and gladly give them a try. If in fact they are marketed under a brand I have already mentioned don't bother because myself and thousands of other US hams have had or are experiencing the same problems with these products daily. Ameritron has piles of them that have been returned.
Best Regards,
Mitch 
W4COX
  ----- Original Message ----- 
  From: Alek Petkovic 
  To: amps at contesting.com 
  Sent: Wednesday, January 19, 2011 5:21 PM
  Subject: Re: [Amps] 572Bs


  That's certainly different to my experience Mitch.

  The 200+, Shuguang (Chinese) 572B, that I have bought direct from 
  China and onsold to hams in VK have been absolutely superb.

  I have had just 2 failures "out of the box" and none after that in 
  the 7 years that I have been handling them. I have had zero failures 
  of any kind from a similar number of 811A tubes from the same factory.

  The 2 failed 572B's were replaced without question on my subsequent 
  order from the supplier in China.

  Not only are they superb in that regard, they are plug and play with 
  the Cetron variety and they really produce the grunt when needed and 
  their longevity is excellent when care is taken with filament voltage.

  I can't say anything other than I am really impressed with them.


  73, Alek
  VK6APK

  At 11:27 PM 19/01/2011, Mitch Cox wrote:
  >Paul,
  >I am sure you will receive many answers to your question on this 
  >subject. I will give you an answer that pertains to my experience with 572B's.
  >I have built many amplifiers over the years for people using this 
  >tube, only 3 last year and one so far this year. In my experience 
  >the Russian tube is by far superior to what is available from the 
  >Chinese today regardless of the name or label printed on them. In 
  >the past 10 years I have found that the Chinese tubes have about a 
  >40% failure rate new, out of the box here. So far I have had one 
  >Svetlana tube fail to light out of about 50 that has been through my 
  >shop. The Svetlana tubes last much longer and have much higher stage 
  >gain than any of the Chinese tubes that I have tried. I have had 
  >very good luck purchasing these tubes from Frank Krize, K5SVC at 
  >Krize Electronics. I am pretty sure that my experience is not an 
  >exception but keep in mind that a fellow asked a simple question 
  >about a fuse about 5 weeks ago and that lasted at least 3 weeks on 
  >this forum venturing from a simple fuse question blossoming into 
  >fluid induction breakers. There are a lot of people who don't co
  >  nsider the 572B a worthwhile venture but for $150.00 for 3, they 
  > pretty much equal the performance of a 3-500Z.
  >Best Regards,
  >Mitch
  >W4COX
  >   ----- Original Message -----
  >   From: Paul Manuel
  >   To: amps at contesting.com
  >   Sent: Wednesday, January 19, 2011 8:11 AM
  >   Subject: [Amps] 572Bs
  >
  >
  >
  >   Good morning. I'm a new list member and I've really learned a lot 
  > from the archives. The knowledge is much appreciated.
  >
  >   Now a couple of questions...where do most of you buy quality 
  > 572Bs at a reasonable price? What is the final concensus on Chinese 
  > vs Russian tubes? Thanks!
  >
  >   73, Paul K4PDM
  >
  >
  >
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