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Reviews Categories | Electron Tubes | 572B Tubes- China Manu. Help


Reviews Summary for 572B Tubes- China Manu.
572B Tubes- China Manu. Reviews: 30 Average rating: 3.3/5 MSRP: $$35
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K4FLH Rating: 5/5 Nov 12, 2010 11:25 Send this review to a friend
Pretty Damn Good  Time owned: more than 12 months
I've bought and used Chinese tubes both generic and some branded,such as Taylor. I've used them in my amps,Yaesu and Heatkit, and have got them for friends. Out of the dozen or so I've purchased I have had only one go bad in an unacceptable time,two days after I installed it. I contacted the vendor about it and two days later I received a new tube, no hassel. I didn't even have to return the bad one.
I ALWAYS let the new tubes idle for a few hours before pouring the juice to them. Then when I tune the amp I key down at 40-50 watts input and only for the max of 10-15 seconds then let them cool for the same time. Maybe that's why I haven't any of the problem others here have had.
I will continue to buy Chinese 572B's as long as I keep getting the service I've been getting from them.
 
VE3FDT Rating: 1/5 Oct 31, 2009 19:35 Send this review to a friend
QC sucks!  Time owned: 0 to 3 months
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.
 
NZ0T Rating: 3/5 May 29, 2009 07:41 Send this review to a friend
Update  Time owned: more than 12 months
An update to my review below of the Shuguang 572B tubes I got from Chen. My Al-811 started acting up with low power and grid current. Upon investigation I found one tube with a very loose cap that was inop and another with a somewhat loose cap and the 3rd was fine. I put my old 811As back in and the amp is fine now. These tubes were cheap and I got about 2 years of use out of them but I'm wondering if they are any better than good 811As now.
 
N3OQD Rating: 4/5 Mar 23, 2009 20:14 Send this review to a friend
30 second glowing plates?  Time owned: more than 12 months
I have been running these tubes in my AL-811 for over a year with no problems. One thing that is puzzling about the previous post of the plates glowing in 30 seconds and this is supposedly the fault of the tube. The plate glowing is due to the amount of electrons ALLOWED to flow from the filament to the plate. It is the potential on the grid that controls this flow. The more negative the grid the more restricted the electrons are and the tube conducts less. The more positive the grid, the less restrictive it becomes thereby allowing heavier eletron flow to the plate. If the grid is exessivly positive than too much electrons flows. The thorium is then stripped from the filament (killing emission in short order) and the plate glows (overheats) quickly.
 
W8VVG Rating: 0/5 Jan 8, 2009 18:23 Send this review to a friend
Nothing but problems  Time owned: 6 to 12 months
I also purchased a set of 4 572b tubes from jc368 and a back up set (8) tubes. The first set went soft in less than 3 weeks. I returned them and was told by Chen that I was over driving them (80watts) and would not honor the warranty. The second set is on the way out after 15 hours of use. I will make every attempt not to buy Chinese tubes again. Apparently my Dentron Clipperton L does not like them. The plates start to glow after about 30 seconds. I am running the Clipperton L in the low power position and about 600ma current. The original Centron tubes lasted 25 years with the same rig. I also found the tubes to be different lenghts
 
K1FU Rating: 5/5 May 1, 2008 01:40 Send this review to a friend
Shuguan 572B Quad  Time owned: 0 to 3 months
Ordered from jcc368 on e-bay. First of all, these are not generic no name tubes. The visual inspection showed me a heavy duty anode and all internal components were top quality. Shipping and packing were first rate and you cant beat the price, $135 USD. 16 days from order to delivery. One problem, two of the tubes were slightly longer than the others. Chen told me if this were an issue he would resolve it, it was not. 1 year warranty will tell...
 
N2EYE Rating: 5/5 Jan 27, 2008 09:37 Send this review to a friend
Penta's great value  Time owned: more than 12 months
I bought four matched Penta 572b tubes for a homebrew (my first). These tubes took some abuse in the fine tuning that was required to get amp (80-10) running. I run plate at 2600vdc under load and out put is great. I did have to return the tubes after delivery as my heaters are in-series and the resistance of one tube affected the voltaage districution untowardly. THat was no problem. I purchased directly from Penta got a good price and amp still goibng striong after 3 years. Also have an SB-201 with original Cetrons in it but what can you say when tuibesd are that old.?? neil ka2tus NYC
 
4Z5NU Rating: 5/5 Dec 18, 2007 11:54 Send this review to a friend
No problems in 10 Months  Time owned: 6 to 12 months
Ordered a matched quad set of 572B (Feb 2k7) on eBay (the seller - jcc368 ,directly from China, Hong Kong). Fast shipped (same day I ordered) and arrived in 12 days in perfect condition (very well packed- 7 layers). Graphite anode more thicker, unlike the thin metal of previous 811A.
The tubes have same power as the 811A at the same drive.
Total price: 120$ for all 4 include postage to Israel and they work in my homebrew PA, with grounded grid, until today (3 times knock on the wood ...).
Resume: no problems in 10 Months!
http://www.qrz.com/4z5nu
Greetings, 73 and good DX!
 
M0HDX Rating: 3/5 Nov 25, 2006 02:57 Send this review to a friend
rebranded tubes.  Time owned: 0 to 3 months
Tube factories in china.

shuguang factory produce many valves which are frequently REBRANDED BY IMPORTERS AND OEM,s,such transmitting types are often branded with old American/European brands and sold without notification that they are chinese made as are the audio types.

liuzhou factory make many types of valves which are marketed abroad.pm components,a british firm,has golden dragon.

sino factory...there are other tube factories in china,most keep a very low profile.some of these lesser known factories specialize in transmitting tubes such as the 811A,812A,813,3-500Z,4-400,100TH,833 and others.

chances are the tubes in your amp branded with RF parts for example or whatever name they have on them are from the same chinese manufacturer as your friends who have the same tubes in there amp but a different brand name.

I use chinese 811A,s (no brand name)in my ameritron al811 and up to now no problems,good pwr output but i would feel alot better if the tube had been branded cetron,penta labs,rf parts,taylor or amperex,I might of even got a few extra watts with a brand name stamped on the tube.


TAKE A TOUR OF THE SHUGUANG FACTORY IN CHINA.
makes you realize how important tweezers really are.
http://www.ks-hifi.com/artical/shuguang/shuguang.htm

jim,M0HDX

 
KG7TR Rating: 4/5 Sep 10, 2006 11:05 Send this review to a friend
One of two shorted  Time owned: 0 to 3 months
I bought a matched pair of 572B's for my Heath SB-201 from a vendor in Florida. Price was $80. They arrived in less than a week, and were from the Shunguang factory in China. I powered up the amp on a variac with the plate caps off and everything seemed OK. When I put the plate caps on, I noticed the amp would draw idling plate current without the antenna relay line grounded. In fact, the relay was already closed. Some simple troubleshooting revealed one of the tubes was shorted from filament to grid. When I removed the tube and powered it up with just filament power from a bench supply, this was even more obvious. I could actually jumper the grid to one of the filament pins and the filament would glow brightly at the point of the short (only works on the filament pin closest to the short; the other pin had little effect). I called the vendor and they said send in the bad tube and they would replace it. They kept their word - and within a week I had a good tube. So I donít have any problem with the vendor in this case. So far the tubes tune up fine; I will attempt to put them on the air today and see what happens. I believe one of the problems with these tubes is that there is very little spacing from the filament to the grid, so any defects in manufacturing or shocks during shipment could cause a short. As a suggestion, vendors that sell these tubes ought to consider screening them first by putting them into an amp to make sure there are no shorts. That would possibly save some time, frustration and postage for everybody.
 
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