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| Reviews Summary for CHINESE 572B TUBES |
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Reviews: 6
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Average rating: 3.7/5
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MSRP: $varies in price.
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Description: High-mu power triode for use in Class AB2, Class B, Class C RF, and audio amplifiers. The chinese 572B is virtually an exact copy of the original 572B/T160L tube and normally rebranded.
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More info: http://www.tomstubes.com/572b.htm
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write your own review of the CHINESE 572B TUBES.
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VE3FDT
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Rating: 1/5
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Oct 31, 2009 19:33
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QC sucks!
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Time owned: months
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I have bought a matched quad (4 tubes) from an eBay seller in Hong Kong. The price was more than reasonable, the delivery cost and time was good. The quality sucked big time.
Out of 4 tubes all had very nice gold metallic stickers on them saying "QC Passed", beyond that one had a direct grid short causing my amplifier to blow a fuse on applying HV (this required replacing blown grid resistors) and another tube had a loose pin (while this is not an outright failure it causes a plate current spike on applying HV / closing the relay and makes me wonder how much longer this tube is going to survive).
The Chinese vendor agreed to replace the shorted tube, but the one with loose pin is apparently OK for him / her. Only that it has been almost a month now and the replacement tube has not been shipped yet. The concept of QC and standing behind the product you sell seems to be entirely foreign to those guys.
In my personal experience the Chinese 572Bs are about 60% of the price of the other such tubes readily available, the problem is that their failure rate is 50% which makes them more expensive in real terms than other 572Bs offered for sale nowadays. Nobody behind the product either.
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W7EKB
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Rating: 4/5
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Jul 9, 2009 22:05
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OK Tubes
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Time owned: 0 to 3 months
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I bought a pair of Shuguang 572B tubes for my SB-200 from a seller on Ebay at least a year ago, and put them away as spares, since I had several good used Cetrons.
In the last several months the power output has been dropping until maximum power output was only about 350 watts.
So I tested all the remaining tubes I had, including at least 6 Cetrons, 1 Penta Labs, and the 2 new Shuguang tubes.
4 of the Cetrons were practically useless, and the Shuguang tubes showed the best output (naturally). I installed the fairly decent pair of Cetrons, and within only a few minutes, there was a flash in one of them, and the filament got considerably dimmer. Power output dropped by at least 100 watts.
So, I uninstalled those, and installed my "new" Shuguang tubes.
Within an hour after installing them, one of THOSE flashed and exhibited a solid grid-to-filament short.
Examining the tube closely, it looked as though the filament "press" was slightly off-center, putting the filament closer to the grid on one side than on the other.
I had recently bought another SB-200 which had a pair of Shuguangs in it. This particular amp had been abused by a CBer, as the plate coil had been charred nearest the tube on that side, the 10 meter tap had been moved so it would "work better" on 11 meters, the plate tuning capacitor had been "arced" badly, and the 10 meter grid coil had been rewound.
Nonetheless, when I substituted one of the Shuguang tubes out of the CB-ed amp for the shorted one, the SB-200 showed full power output, over 700 watts on 80 meters, and has been working fine ever since.
The way I see it, since an NOS 572B from AES costs $152.00 EACH, I can buy 4 of the Chinese tubes for that amount and lose two and still make out.
However, I DO wish QC in the Chinese tubes was better...
There is a fellow on eBay who sells Svetlana 572Bs for a fair price. He says that the Chinese tubes have a 35% failure rate.
So far, since I have 4, and one has failed, I have experienced a 25% failure rate.
Now, I will see how long these good ones last, and will report back in a few months.
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KX5JT
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Rating: 5/5
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Mar 31, 2009 05:49
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Strange!
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Time owned: 0 to 3 months
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So I put that matched pair back into the SB-200 after a while and the plates DO NOT turn very red at all now. I have NO IDEA what happened. Same settings on the amp, same loading.... maybe the getters weren't complete and the red plates finished them? At anyrate, they are working FB now! Mysterious but I'm happy!
KX5JT
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KX5JT
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Rating: 2/5
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Mar 11, 2009 01:34
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Stay away from Shuguang 572Bs!!!
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Time owned: 0 to 3 months
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Hello everyone. This is a warning to stay away from Shuguang 572B tubes as direct replacements for amps designed for 572B's. I own a Heathkit SB-200 and decided to try a matched pair. After ordering direct from Hong Kong from that JCCsomething fella on Ebay, they arrived at my home well packed and timely. No problems there. The problem is when you put 2400 volts of plate voltage on them as the original 572Bs are specified for and as many of the amps that use 572Bs utilize. The plates will glow a BRIGHT CHERRY RED in less than a minute of talking with ssb. RTTY will have them glowing RED HOT in less than half a minute. Graphite anodes should just barely blush a deep red not a bright red hot cherry red. I found out the reason too. See here....
http://www.analogmetric.com/forum/viewthread.php?tid=223
Check the specs on those Shuguang 572Bs... they are only rated for 1250volts on the plates. THAT IS less than HALF of the voltage rating of original 572Bs... .unless you are designing your own amplifier/transmitter with this low plate voltage, this is useless for replacing 572Bs. Real 572B's should be able to take 2750 volts on the plate in intermittent amateur service. My Sylvania Made in the USA 572B's barely blush when I run AM continuous carrier or heavy duty RTTY or SSTV. You have been forwarned! Svetlana 572B's from the 1990s maybe a better choice. I understand the newer Svetlana 572B's were designed with audio in mind and they may not be a good choice. Anyway, I am in the process of putting a matched pair of NOS Svetlana 572B's through a burn in and will report on my findings with them in the near future. *Sigh*
Caveat Emptor
John KX5JT
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N3OQD
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Rating: 5/5
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May 12, 2008 20:52
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brief overview
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Time owned: 6 to 12 months
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I put a set in my Ameritron AL-811. In this application they serve me quite well. With the larger graphite anode of the 572B in the stead of the 811a's tin steel type, these are more forgiving and more durable. Even Ameritron recommends this upgrade with no hesitation. 40w drive gives me about 400w out SSB consistantly. Have a set in the wings but I may never need them. $75 plus shipping for the three from China on e-bay
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K4SPS
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Rating: 5/5
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Jun 27, 2007 21:05
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Have had great luck with these. Thank God for the Chinese, Ha!
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Time owned: 0 to 3 months
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I ordered, directly from China, a matched set of four 572B's for my 'new' Collins 30L amplifier. They arrived in perfect shape and tuned up with no problems. They run cool and efficiently in this classic amp. Will probably buy a spare set to have a lifetime supply of valves. I highly recommend them; hopefully, you will have similarly good luck! K4SPS
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