| N7XCZ |
Rating:     |
2022-04-22 | |
| no problems so far |
Time Owned: 0 to 3 months. |
PS Vane 572b tubes, shipping arrived early so a plus
also they seem to be working very good I had Shuguangs before these they did not last over two years. I am using them in an Ameritron Al-572 on 120V. After burn in
160 meters key down 1000w 45 watt input
80 meters key down 1000w 45 watt input
40 meters key down 1000w 45 watt input
20 meters key down 1100w 45 watt input
17 meters key down 700w 45 watt input
12 meters key down 700w 45 watt input
10 meters key down 600w 45 watt input
600 watts easy on RTTY and DIGI modes on
160 through 20 but usually run at 500 watts 400 on the higher bands and 1000 Watts on SSB 160 through 20
a little less on the higher bands. I don't run AM
It might do more with 220v and less strain on the Amp which I think I am going to install in the shack soon
Over all pleased so far
Ed Wolf
N7XCZ |
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| K0UA |
Rating:  |
2021-04-01 | |
| Be careful where you buy them |
Time Owned: 0 to 3 months. |
| I bought Chinese 572B's straight from China. In other words I did not go to a reputable tube reseller here in the US. They arced badly in my AL-811H and blew Diode D16 and the fuse. A beautiful purple storm on the inside of the tubes. I returned them, and had a hard time getting my money back. Eventually paypal/e-bay helped get the money. I would suggest if you are going to buy these tubes to buy from a reputable dealer who will actually test them and weed out the defective ones. Quality control sucks on all Chinese tubes, they have to be tested and the bad ones sent back to the same Chinese plant they all come from. Buy with care. |
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| W5ZYX |
Rating:    |
2021-03-31 | |
| Using PSVANES--So far, so good |
Time Owned: 0 to 3 months. |
I recently ordered four PSVANE branded 572B tubes, which are now offered through Amazon. The tubes arrived from China after about two weeks and I installed them in my AL-811H amplifier.
Interestingly, as soon as I turned the amp on, I immediately began seeing plate current readings jumping around between 0 and 170 mA. I quickly switched the amp off, and when I turned it back on in a few minutes, the plate current remained at 0. One does not expect to be seeing a flow of plate current with an amplifier in standby mode.
I began running FT8, limiting grid current to 140 mA and shortly the grid reading began dropping to 90 mA though the power output remained at just under 300 watts. I again switched the amp off and after a cool down of about an hour, switched it back on. From that point on the tubes became stable though as the amp warms up in operation, it requires periodic small increases in drive power to maintain a grid current reading of 120 mA. From a cold start, 15 watts drive produces 120 mA. After about 30 minutes of fairly active FT8 operation, grid current and power output remain constant at about 250-270 watts with 28 watts drive and no ALC reading on the FT-991A that I am using to drive the amp in FT8 operation.
Bottom line, I have now been using the PSVANE tubes for three weeks and operating on FT8 on 20 or 40 from 2-3 hours daily. Keeping my fingers crossed, but they were reasonably priced insofar as 572Bs go and so far, so good.
Considering the initial spurt of plate current readings with no drive applied and the later drop in grid current while in transmit operation, I suspect one of the tubes was likely gassy, but that problem hasn't recurred. Keeping my fingers crossed. |
|
| N8FVJ |
Rating:    |
2019-05-09 | |
| Ok at Best Rating |
Time Owned: more than 12 months. |
A good set of Chinese 572B can last perhaps 5000 hours whereas old Centron are known to last 25000+ hours. Of late (last 2 years?) quality seems to have improved as duds after 50-100 hours use do not seem to be present. But, 5000 hours use makes the Chinese 572B very expensive in the long run.
You would be better off buying $320 a pair of NOS Cetron from RF Parts vs five pairs of Chinese for same life expediency. Interesting that the Chinese 3-500Z lasts over 10 years and still performing well in amplifiers. |
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| AA5KG |
Rating:      |
2018-12-05 | |
| 572's are working well |
Time Owned: 0 to 3 months. |
I bought a set of four Machlett branded 572B tubes about two months ago from a seller in Los Angeles on eBay (about $55 each). These tubes are the same as other 572B's coming out of China, just with a different brand name. After receiving, I carefully inspected them under a large magnifier. All four tubes were practically identical with no visible issues.
I removed the six-month old 811A's from my Ameritron AL-811H amplifier and installed the new 572B's. Following advice found on other web sites, I tied back the plate connectors, put the cover back on the amplifier, and let the filaments operate without using the amplifier for around six or seven hours. Again, no issues were observed, so I opened the amplifier back up and attached the four high voltage plate connections and put the cover back on the amp.
I have now been using the amplifier for around 3 to 4 hours every day for over a month, and the tubes have been performing very well. The AL-811H amp is rated for 800 watts PEP output with either 811A or 572B tubes installed, but I think that number is a little high myself. With the original 811 tubes in the amp, it usually put out around 650 watts. With the 572B tubes, the amp now puts out around 750 watts. No modifications were made to the amp - simply replaced the original tubes with the 572B's.
Considering the negative reviews of these tubes, either the quality coming from the manufacturer has improved, or I just got lucky and obtained a good set. But it seems to me that they have improved their QA process in response to all the negative comments seen in the recent past.
I know it's somewhat early to tell whether these tubes will last, but all indications are good so far. I'll post an update if any problems surface.
All things considered, I am very satisfied with these tubes in my AL-811H amp. The original (perfect condition) 811A's are carefully packed away as spares, but if this set of 572B's continue to perform well, I will order another set and keep them as backup.
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|
| WA8NSS |
Rating:  |
2017-01-30 | |
| Still poor quality! |
Time Owned: 3 to 6 months. |
| I have been through 2 sets (4) tubes in my sb201 in a period of 4 months as both sets went soft prematurely. My 201 has been refurbished with all harbach mods except stepstart and filament voltage is where it should be at 6.3 volts. I reinstalled my old tubes (cetrons) and all is well. Rf parts was good at backing up their warrany for a full refund. However, all 572b tubes are manufactured in one place and that is China, if you purchase these tubes from whomever and they have a warranty make sure you use your amp often, at least until you get 30 hours on them and if your output doesn't drop you probably have a good set. Make sure you can tune your amp up quickly and only drive with 60 to 70 watts for tube longevity.! |
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| N4QCV |
Rating:     |
2014-01-07 | |
| 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 |
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| W7EKB |
Rating:  |
2013-12-26 | |
| 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:      |
2011-09-14 | |
| 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"
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|
| SV9OFO |
Rating:      |
2010-12-29 | |
| 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 |
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