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Author Topic: 572B testing  (Read 9476 times)
K0ZN
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Posts: 1553




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« Reply #15 on: October 07, 2012, 09:42:44 PM »


  It is all of those tubes...   I went through six new 811A's to find three that have lasted in service.  Two of the new tubes were gaseous from
the get go and on lasted a couple of weeks before the vacuum failed.  So far, the "good ones" have run trouble free for over a year.......
I ended up building a test/burn-in device for 811A's, figuring that tube replacement was going to be a common event and I wanted a
shot at knowing how good/bad a new tube was before putting it in service in the amplifier.    "Are we having fun yet??...."

 From what I read and hear, the 3-500Z's are generally better/more trouble free than the 811A's and 572B's.

73,  K0ZN

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W8JI
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« Reply #16 on: October 08, 2012, 12:23:56 AM »

I don't have hard statistics on 3-500Z tubes, but my gut feeling is they are better out of the box than other tubes. 3-500's still are far from what they were when Eimac was making them, however. The dominant failure seems to be short emission life.
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AH6RR
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« Reply #17 on: October 08, 2012, 12:19:13 PM »

It would be nice if Eimac went back to making the 3-500Z even if they cost $250-300 each at least we would know they were made right and of proper materials and in the USA. I have a pair in my SB-220 that have a date code of 7916 16th week of 79 and still have full output.
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W8JI
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« Reply #18 on: October 08, 2012, 05:25:53 PM »

It would be nice if Eimac went back to making the 3-500Z even if they cost $250-300 each at least we would know they were made right and of proper materials and in the USA. I have a pair in my SB-220 that have a date code of 7916 16th week of 79 and still have full output.

Such moves never wind up being a bargain long term to USA consumers, do they?

Eimac will never get back in the business of glass power grid tubes. They sold the tooling and fixtures to Triton in Pennsylavania, and they went bust. The last batch of 50-100 Eimac 3-500Z tubes Ameritron bought , just before the move, were 100% bad.
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KE5JPP
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« Reply #19 on: October 09, 2012, 03:01:43 AM »

It would be nice if Eimac went back to making the 3-500Z even if they cost $250-300 each at least we would know they were made right and of proper materials and in the USA. I have a pair in my SB-220 that have a date code of 7916 16th week of 79 and still have full output.

If some USA company manufactured the 3-500z like the Eimac 3-500z which lasted 30+ years (manufactured in '79) and the demand is only a couple hundred tubes per year, how the heck would they stay in business?

Gene
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PA1ZP
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« Reply #20 on: October 11, 2012, 04:51:50 PM »

Hi to all

I do have a AL572BCXE

10 mtrs doesn't work due to RF choke having trouble and overheating.
572B's tubes wich came with the amp are Chinese and are not very good quality.
One of the 572B's had a loose rattling anode .

I bought 18 new 572B's in China.
3 sets for back-up replacement for friends of me wich 2 had an 811 amp one also has an AL572B.
1 set for myself.
I payed 540 Euro,s including taxes and shipping.

One of my ham friends has an AL572B wich came with the Svetlana tubes.
He uses his amp a lot and these tubes do not go soft at all yet.
Though the Sveltlana's have a smaller anode electron emission seems to be longer lasting as with the Chinese tubes 
My Chinese ones wich came with the Ameritron (they look like Shuguans) went soft rather fast with bad electron emmision.
The new Chinese work wonderfull though I do not use the amp very often , it has to be seen how electron emission behaves and gassing in time.
They were of different manufacturer (not Shuguan)  and one of them also had loose rattling anode inside glass envelope .
The tubes I bought had dates written on a ceramic part inside the tubes and were very recent only 1 yr old 
The tubes were beautifully packed each, and very well protected in a box together and shipping was very fast and without troubles

If I had to buy another amp again it would be an AL80B with just one 3-500 .
The extra 300 Watts from the AL572B do not weigh against the trouble you can have with 4 572B tubes

As I am a very "nostaligic man" with great love for technics from the past, I make small retro items for in my shack, I use little 12AT7 for ON/OFF indicators and TX/RX indicators.
Together with the brushed stainless steel cabinets these little things like my noise canceler or balanced tuner or 4-square controller look very pretty and are a pleasure to see.
I am planning to update the cabinet front and top and sides of the AL572B to fit the look of my stainless steel paddles and other homebrew items.

the plan is to wrap my AL572B in new engraved brushed Stainless steel front and upper top and sides.
So it will fit my "Антонов" noise canceler and "союз" tuner and "Енергия" 4-square controller.
Also the perforation on the side will be a bit different and fit with a fine wire mesh so I can see the gloing tubes much better.

I think I will call the AL572B  EA1JC   The royal Amp. hihi
Or it will be called "чернобыль" because it may be also a disater to happen.

73 Jos 
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