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Reviews Categories | Electron Tubes | CHINESE 572B TUBES Help


Reviews Summary for CHINESE 572B TUBES
CHINESE 572B TUBES Reviews: 11 Average rating: 3.8/5 MSRP: $varies in price.
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.

Product is in production.
More info: http://www.tomstubes.com/572b.htm
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N4QCV Rating: 4/5 Jan 7, 2014 18:29 Send this review to a friend
572 B TUBES  Time owned: 0 to 3 months
IVE FOUND SOME PENTA 572 B TUBES AT AMERICAN MILSPEC LLC FOR 39.95 EACH I DONT HAVE A AMERITRON 811H AMP YET BUT AM LOOKING FOR A GOOD PAIR FOR EXTRAS WHEN I GET THE AMP NEXT YEAR. HERE IS THE LISTING IN THE AMERICAN MILSPEC PAGE......


RF power tube Penta 572B / T160L NOS


RF power tube Penta 572B / T160L NOS,

SKU: tube7-2231
Dimensions: 2x2x3
Weight: 1.00
Price: $39.00
 
W7EKB Rating: 1/5 Dec 26, 2013 10:35 Send this review to a friend
2nd Follow-up.  Time owned: more than 12 months
This is another follow-up on my previous reviews of these tubes.

I installed a brand-new pair of the Shuguang 572Bs in my restored and properly-operating SB-200 on April 23 (my birthday), 2013.

By December of 2013, max grid current began slowly dropping, while power output was also slowly dropping, now at about 400 watts for the pair. I am now unable to get grid current for the pair to increase above 50 mA/pair, no matter the level of drive. This activity follows my previous experience with these tubes: in no case has a pair of them lasted longer than 12 months at the best.

During the approximately 7.5 months of near-daily use, I very carefully kept maximum grid current for the pair of tubes to less than 70 mA, or 35 mA per tube. I always tune for maximum GRID current, keeping the grid current below 70 mA by reducing the drive level. Plate current was ignored, and seldom allowed to rise above about 400 Ma. Power output was purposely kept to 500 watts or less. Drive power for 500 watts output was always less than 50 watts from the exciter.

For this pair of tubes, I purposely chose a different seller than those I have used previously. This seller insisted that his tubes were carefully tested for QC, and I found his claims to be true. The tubes installed and ran immediately with no "issues".

Despite this, this pair lasted no longer than those I have used before.

Today, 12/26/2013, I have installed another pair which I bought from a Chinese seller on eBay. Although the tubes work as well as any previous properly-tested pair has when first installed, the grid current and power output of this pair "flickers" a bit. We'll see if this issue "goes away" as they are used, or if it results finally in a grid-to-filament short as others have.

Unfortunately, despite the poor quality of these tubes, they are all that are now available for the many 2 X 572B amplifiers that are being used these days. I suppose the cost of buying a new pair of tubes every 6 to 8 months is the price we are going to have to pay to keep our equipment in operation. Unless...

I see that RF Parts has recently announced that they are no longer selling any 572Bs until those they are having manufactured are available sometime after January 2014. RF Parts' quality has always been superb. Thus, I am hoping that they are having 572Bs made to much higher quality standards than those available up to now. I am awaiting any such news with extreme anticipation.
 
VK4VDX Rating: 5/5 Sep 14, 2011 21:29 Send this review to a friend
beyond your control  Time owned: more than 12 months
Shipping damage is the only problem you will have with this Tube, they are always boxed well and still there is a big chance of them arriving damaged. Having lived in China and experienced EMS (freight company) first hand.
If you want to send a parcel, EMS is great, they will pick up your parcel with a bicycle from your home or office and take it to the next depot, surprising how much they can fit on that bike and than you got customs if they check the parcels on the way out of the country not knowing what is really in the parcel. the same can happen on the way into your country. So my suggestion is, if you need 2 tubes, buy 4, because if 1 tube breaks you will be asked to send that tube back to china, that's if they offer to replace the tube but most of the time you will get told if the tubes get damaged during shipping the tubes will not get replaced free of charge.
That's why my Tubes have come in my mother in laws hand luggage the last time she arrived from China for a visit.
I have had some excellent reports of a technician who has really put the tubes to the test and he told me on more than one occasion how surprised he is about the quality of these tubes. That's why I will give these tubes a "5"
 
SV9OFO Rating: 5/5 Dec 29, 2010 00:08 Send this review to a friend
I ACTUALLY BOUGHT THEM FOR BREAKING THEM!!!  Time owned: 0 to 3 months
No problems at all. Have bought them after installing major PSU safety upgrades (all amps should carry those, as a 300 mA per tube fuse at HV and a 22 ohm R in series) and during the refurbishment of my FL-2100Z, for not breaking my pair of new Cetron's.

Drop-in replacements for Cetron, they had undergone enormous stress during the testing phase. Key down 600W carrier for minutes boiling my dummy load's oil - no failure. Some graphite glow but no harm.

My chinese friends busted through a TI pileup yesterday morning (I reside in southern Europe).

Did that AFTER the punishment.
My Cetrons are still in the box, and probably will remain there for long as I see it.

Will definately buy again.

73
 
N1CKX Rating: 5/5 Sep 28, 2010 17:56 Send this review to a friend
Working Fine  Time owned: 0 to 3 months
Ordered 4 Shuguang 572b tubes from E-bay/China to back up the tubes in my MFJ/Ameritron AL-572 amp, as I had a bad one in the Amp from the factory (another story).

Arrived in a week, well packaged. Gave them a careful inspection under high magnification for bent/distorted elements, and then checked them for shorts.

Installed them in the amp and have been running them for over a month with no issues.

Carefully measured the output with a calibrated dummy load and a 200mHz scope and output is around 1380 watts PEP. Pretty darn close to legal limit. Not bad for less than $150.00 for four tubes.

My original tubes are (a month later) still at MFJ/Ameritron. Way to go MFJ/Ameritron.
I would have an $1800.00 paperweight if I had not purchased backups.

I suspect the tubes that short are going into old Heathkit Amps that mount the tubes horizontally.
These tubes are rated for vertical mounting. Elements can sag when horizontal and short out.

The original tubes in those amps were special construction for Horizontal mounting.

Iím holding my breath, but will give them a 5/5 for now.
 
PA1ZP Rating: 4/5 Aug 11, 2010 00:28 Send this review to a friend
Service OK  Time owned: months
Hi All

I bought 18 572 tubes at factory in China.
Delivery was perfect packaging perfect, price perfect.

Only one tube was not 100%, it rattled loose anode in glass envelope.

17 tubes were OK.
In use now fer 6 month, no problem at all.

You can complain abt the one defective tube , but with my Ameritron on delivery came a tube with the same defect.

It was only after arrival of 18 the chinese tubes that I found out what was the problem with the original set of tubes.
One was defective from day one (not causing serious touble but just strange noises from vibrating anode against glass envelope)
Noises are gone with new set of tubes installed

Original Chinese set of Ameritron was in service for 3 yrs and completely warn.
(they had a hard life with 1KW key down in CW and I tend to TX for more then 20 minutes at a time without pause), they had to work full pull 70% of my QSO's, 100 watt in and 1KW(+) out fer 1 hour or more every day.

I couldn't get over 800 watts key down anymore and SWR at input was becoming higher.
Anode current would not pass 575 mA no more, even with 100W input.
But after 3 yrs Anode top resistor and coils 100% and grid resitors 100% like new.

New set was Ok from day one.
No more strange noises.

I know that the 572B and the AL572B amp are not the best in town but 4 tubes cost me 120 Euro's now, if they last another 3 yrs I am quite happy.
You have to be realistic AMP is cheap tubes are cheap don't compare the 572B with a 3CX1500 or 8877m, though our chinese friends at High Hope International deliver up to 3CX50000.
3-500 3cx1500 3cx800 etc. all produced by them in China.
 
VE3FDT Rating: 1/5 Oct 31, 2009 19:33 Send this review to a friend
QC sucks!  Time owned: 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.
 
KX5JT Rating: 5/5 Mar 31, 2009 05:49 Send this review to a friend
Strange!  Time owned: 0 to 3 months
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
 
KX5JT Rating: 2/5 Mar 11, 2009 01:34 Send this review to a friend
Stay away from Shuguang 572Bs!!!  Time owned: 0 to 3 months
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
 
N3OQD Rating: 5/5 May 12, 2008 20:52 Send this review to a friend
brief overview  Time owned: 6 to 12 months
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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