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Re: 3-500 tubes
Ex was a typo
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On 2024-05-23 10:15, Amp Guy Llc wrote:
Eimac 3-500z tubes usually have zero leakage to 5k ex and beyond, grid to cathode |
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Re: 3-500 tubes
Eimac 3-500z tubes usually have zero leakage to 5k ex and beyond, grid to cathode
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On 2024-05-23 09:03, Jim VE7RF wrote:
Careful with any hi-pot test results. You can easily skew the |
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Re: 3-500 tubes
Careful with any hi-pot test results.? You can easily skew the results, depending on what leakage current you have it dialed up to.?
And ua leakage is not linear? vs applied voltage either.? Typ 5-10ua is the limit for hi-pot tests....and even then,? I would leave it applied for at least 10-20 mins.? ?I have seen some cases, on some items, where the leakage is initially low with XXX? volts applied, then after just 2-3 mins, the leakage current starts to increase....then really ramps up.?? |
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Re: 3-500 tubes
¿ªÔÆÌåÓýJim, ????????? This not only applies to 3-500Zs it applies pretty much to anything coming out of China. For 32 years I worked for the ¡®big teal hourglass¡¯ where we made API¡¯s, (active pharmaceutical ingredients), for some of the best medicines. I won¡¯t go into the ¡®George Merck mantra¡¯ they fed us but the last 15 years we got raw materials from China that were of suspect quality. The expectation was that we were to make a ¡®silk purse from a pig¡¯s ear!¡¯ They hammered away at our output quality but when we challenged corporate on the quality of the raw materials they said, ¡°Well, we can eat the loss for that. Just make a better product!¡± Now they are making the last 2 broad spectrum anti-biotics (beta lactams), in Italy! ????????? Mod-U-Lator, Mike(y)/W3SLK ? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF ? If Tom is seeing 1.5 kv to 5 kv, and typ 2kv..... between grid and cathode, he just finally got a 'good' batch of tubes.? ?What about the next batch ?? ? Hopefully, the chinese factory #1? can find some consistency in their production runs.? ?There should not be the wild fluctuations in test results.? The Eimacs were always 100% consistent. ? When Tom started buying tubes directly from China...the bad tubes got tossed.... and? he was credited on the next batch.? Perhaps the chinese have figured out that since they are only getting paid for tubes that actually pass the tests, it might be in their best interest to build em right the 1st time around.? Like what's the point of building a bad tube, then paying to ship it to NA,? only to have it tested, fail the test, then tossed...then have to credit the buyer on the next batch.? My guess is, with a 15% or less failure rate, they are still making money...and that a 15% or less failure rate was acceptable.?? |
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Re: 3-500 tubes
If Tom is seeing 1.5 kv to 5 kv, and typ 2kv..... between grid and cathode, he just finally got a 'good' batch of tubes.? ?What about the next batch ?? ? Hopefully, the chinese factory #1? can find some consistency in their production runs.? ?There should not be the wild fluctuations in test results.? The Eimacs were always 100% consistent. ? When Tom started buying tubes directly from China...the bad tubes got tossed.... and? he was credited on the next batch.? Perhaps the chinese have figured out that since they are only getting paid for tubes that actually pass the tests, it might be in their best interest to build em right the 1st time around.? Like what's the point of building a bad tube, then paying to ship it to NA,? only to have it tested, fail the test, then tossed...then have to credit the buyer on the next batch.? My guess is, with a 15% or less failure rate, they are still making money...and that a 15% or less failure rate was acceptable.?? |
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Re: 3-500 tubes
You are forgetting the grid to cathode test specs.
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The China tubes usually hi pot to 1kv grid to cathode at best maybe a hair higher. Inter-electrode capacitance is roughly double of the Eimac spec. This screws the input swr up a bit on the higher bands for amps with a tuned input. This goes for all the China white base tubes. When one fails or bad to begin with 99.9 percent of the time it is from a grid to cathode short. I have only seen a couple fail anode to grid but was due to shipping damage. I have handled thousands of white and brown base China 3-500z tubes. Jim can explain the test jig Tom and Ameritron uses to weed out the tubes with a grid issue. Scott On 2024-05-22 10:16, W7WRX wrote:
I dont think you are in his group? He has been selling and testing |
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Re: 3-500 tubes
¿ªÔÆÌåÓý
I dont think you are in his group?? He has been selling and testing these for 4 years now.? ? Since you might not be in there, I can post the Hi pot data here:
"These tubes all tested good, 24 out of 24. The highest high pot anode to grid was 15 kV, the lowest was 11 kV.
The highest grid current for emission saturation at 2800V anode was 190 mA, the lowest 170 mA. The lowest peak output at emission limiting at 2800V was 1050W at 5V filament, the highest was 1200 W.
Grid high pots were 1500-5000V at 10uA leakage, with most around 2000V. The 5kV tubes had ~15 kV anode. They must have a really hard vacuum."
From: [email protected] <[email protected]> on behalf of Jim VE7RF via groups.io <jim.thom@...>
Sent: Wednesday, May 22, 2024 7:17 AM To: [email protected] <[email protected]> Subject: Re: [ham-amplifiers] 3-500 tubes ?
On Tue, May 21, 2024 at 05:54 PM, W7WRX wrote:
##? Test any chinese 3-500Z? with a hi-pot tester.? You won't measure? 5 kv? between grid and cathode....like you see on any Eimac 3-500Z.? ? The best you will measure is 1 kv, if that....and sometimes as low as 600-700v.? ##? You won't measure 16-18KV,? from anode to grid, like on any Eimac 3-500Z.? ##? The measured C? between grid and cathode on the chinese 3-500Z's is far more than an eimac.? ?The chinese tubes have the grid spaced closer to the cathode vs? Eimac.? ?The MU on the chinese tubes is 200.? The MU on the eimac 3-500Z is just 130.? The chinese? 3-500Z's? will work fine.... as long as they have the white base...and are matched correctly, if a 2 x tube amp used.? On eimac 3-500Z's.... grab any random pair of new eimac 3-500Z's.... and they are matched up.... since they were? built to exact specs.?? |
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Re: 3-500 tubes
On Tue, May 21, 2024 at 05:54 PM, W7WRX wrote:
##? Test any chinese 3-500Z? with a hi-pot tester.? You won't measure? 5 kv? between grid and cathode....like you see on any Eimac 3-500Z.? ? The best you will measure is 1 kv, if that....and sometimes as low as 600-700v.? ##? You won't measure 16-18KV,? from anode to grid, like on any Eimac 3-500Z.? ##? The measured C? between grid and cathode on the chinese 3-500Z's is far more than an eimac.? ?The chinese tubes have the grid spaced closer to the cathode vs? Eimac.? ?The MU on the chinese tubes is 200.? The MU on the eimac 3-500Z is just 130.? The chinese? 3-500Z's? will work fine.... as long as they have the white base...and are matched correctly, if a 2 x tube amp used.? On eimac 3-500Z's.... grab any random pair of new eimac 3-500Z's.... and they are matched up.... since they were? built to exact specs.?? |
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Re: 3-500 tubes
Who said anything about Tom and the tubes he sells not having a white base ??
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I was referring to the link on here for Henry radio and the greenstone 3-500c Which has a brown base, according to the picture. On 2024-05-21 09:54, W7WRX wrote:
The tube He sells clearly a white base tube. Check this link. He |
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Re: 3-500 tubes
¿ªÔÆÌåÓý
The tube He sells clearly a white base tube.? Check this link.? He had them change specs on these and had to purchase hundreds of them to test before they finally got a good batch.? These exceed Eimac spec now.
By the way, Someone pointed out that RF parts no longer have 3-500 tubes listed for sale.? They seem to be all gone from the listings.? There are a few multiple tube sets listed and that's all.? Maybe a website issue or a parts issue.? Not sure.? ?I will have
to check back to see if they show up again.
From: [email protected] <[email protected]> on behalf of Jim VE7RF via groups.io <jim.thom@...>
Sent: Monday, May 20, 2024 11:03 PM To: [email protected] <[email protected]> Subject: Re: [ham-amplifiers] 3-500 tubes ?
The tube in the link has the brown base.? That comes from factory #2..... which per JI, has a 70% failure rate.? ( how the hell factory #2 stays in business baffles me).? ? Factory #1 has the white base...and has minimal tube failures.? |
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AL80B - QSK-5PC board problem
I have a AL80B with a factory installed QSK-5 board. (new 2019)
The amp xmit fine.
Receive is down. Typically it's those stupid fuse lamps Lp1, Lp2....
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Open cover, remove Lp1/Lp2 -- install new ones.
Turn on AMP
no problem, receiving fine. Turn STBY /XMT OPR on.. poof, lamps blow out.
Try with nothing connected to amp, no control lines, nothing.
Replace L1/L2, turn on amp, fine.
Flip up XMT OPR , lamps blow out.
?
Amp now has low receive, and plenty of output, receive is down -20 -30db .
.
All bands.
Anyone seen anything like this?l've replaced these lamps 1x in
?5 years, and it was a no brainer.
Something in the receive chain? Pin diodes?
?
ARGH..
Glenn |
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Re: 3-500 tubes
Be careful with greenstone USA.? I have read of several end users (broadcast? FM) that had one helluva time with greenstone USA when it came to warranty issues.? This was with metal triodes / tetrodes.? That was 2 yrs ago.? Henry radio liked the greenstone brand, and was using em as a replacement tube for their 8K ultra...... then in the same breath was on about the grid to cathode short issue with that tube.? But that may have been a bad batch of tubes, dunno.? The tube worked fine for several months, then developed the grid to cathode short.? ?This is yet another reason to step start the fil.? My Svetlana 3CX-3000A7's? came with a? spiral mesh style cathode.? ?I can see issues with grid to cathode shorts on those too, if some form of step start / current limiting is not employed.? ?The henry RF generators used a special type of 50 amp fil xfmr, that was current limited to 100 amps.? It works, but, myself, I would want the max, peak inrush current to be a helluva lot less than that.? ? On buddy's 3x6 amp, ( built 2007-2008)? it used a small variac for the fil xfmr AND also? conventional relay to shunt out the step start resistor. The variac was tweaked, then left alone.? ?The step start was used each time the tube fil turned on.? The other method is variac only....and just bring up the variac (slowly)? to whatever vac you want.? Then the panel fil ammeter just comes up like.....0-1-2-3-4........50 amps.? There is never any surge.? ?When done for the night, variac turned down slowly.... to zero amps....and zero? vac.? Then the toggle kills the power to the variac.? |
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Re: 3-500 tubes
The tube in this link that was posted has a brown base
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It is what I was talking of. 73 Scott On 2024-05-20 10:24, W7WRX wrote:
They sell only the white base tubes. Never the brown. He actually |
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Re: 3-500 tubes
¿ªÔÆÌåÓý
They sell only the white base tubes.? Never the brown.? He actually has an article showing exact difference and performance between them.??
He worked with the factory in china to get the tubes to his specifications and now they exceed Eimac and amprex.? The original tubes did not pass. They are all Hi pot tested and tested with RF before being shipped.
C
From: [email protected] <[email protected]> on behalf of Amp Guy Llc via groups.io <kb1sel@...>
Sent: Sunday, May 19, 2024 9:52 AM To: [email protected] <[email protected]> Subject: Re: [ham-amplifiers] 3-500 tubes ?
The tube in that link is the brown base , it is the less favorable of
the two Chinese factories. Tom W8ji has explained the failure rate between one and the other. I haven¡¯t used the brown base type in years. Are cheaper though. Again I will note that all of the white base ones come from the same factory. 73 Scott MOn 2024-05-19 10:20, Alan - W5ARM wrote: > [Edited Message Follows] _On Sat, May 18, 2024 at 11:52 AM, Joe - > W7RKN wrote:_ > >> _It appears I have a shorted 3-500Z tube in my AL-82 amplifier._ >> >> _It also appears that right now the 3-500Z or ZG tubes are >> unobtainium._ >> >> _..._ >? 3-500's are nowhere near the "unobtanium" status.? Getting expensive > now? Yes... but still quite readily available. While the original > Eimac's are getting harder & harder to find (and those that are > available are quite old), the Chinese ones are fairly plentiful. > > Not sure about the reliability/longevity of the Penta-brand tubes. > They've been around a while, but the company itself is a bit checkered > (their "facilities" in the greater LA area have changed locations many > times in the last few years). The same "company" (location) also sells > the "Machlett" brand (although they are also ChiCom).? I also now see > the "Amperex" brand being sold (eBay), but they too are no longer a > US-made tube... "assembled in China". > > Henry Radio in Los Angeles sells a ChiCom version (a 3-500C) for a > fair price, and it comes with a one-year "guarantee".? I've been > running a pair of these in a couple different amps (swapping them > between a Drake L-4B, and a Henry 2-KD Classic) for a couple of years, > without any issues. > > They can be ordered direct from Henry radio, HERE: > > > I have no affiliation nor interest with them, just a satisfied > customer (I own a few Henry's!) > > Good luck! > > ON EDIT: Sorry for the multiple edits. For some reason the Henry tube > link wasn't working... My appologies. > -- > 73, > ~Alan > > > Links: > ------ > [1] /g/ham-amplifiers/message/40396 > [2] /mt/106173952/8135091 > [3] /g/ham-amplifiers/post > [4] /g/ham-amplifiers/editsub/8135091 > [5] > /g/ham-amplifiers/leave/12941173/8135091/773995006/xyzzy |
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Re: 3-500 tubes
The tube in that link is the brown base , it is the less favorable of the two Chinese factories. Tom W8ji has explained the failure rate between one and the other.
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I haven¡¯t used the brown base type in years. Are cheaper though. Again I will note that all of the white base ones come from the same factory. 73 Scott MOn 2024-05-19 10:20, Alan - W5ARM wrote: [Edited Message Follows] _On Sat, May 18, 2024 at 11:52 AM, Joe - |
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Re: 3-500 tubes
On Sat, May 18, 2024 at 11:52 AM, Joe - W7RKN wrote:
3-500's are nowhere near the "unobtanium" status.? Getting expensive now? Yes... but still quite readily available. While the original Eimac's are getting harder & harder to find (and those that are available are quite old), the Chinese ones are fairly plentiful. Not sure about the reliability/longevity of the Penta-brand tubes. They've been around a while, but the company itself is a bit checkered (their "facilities" in the greater LA area have changed locations many times in the last few years). The same "company" (location) also sells the "Machlett" brand (although they are also ChiCom).? I also now see the "Amperex" brand being sold (eBay), but they too are no longer a US-made tube... "assembled in China". Henry Radio in Los Angeles sells a ChiCom version (a 3-500C) for a fair price, and it comes with a one-year "guarantee".? I've been running a pair of these in a couple different amps (swapping them between a Drake L-4B, and a Henry 2-KD Classic) for a couple of years, without any issues. They can be ordered direct from Henry radio, HERE: I have no affiliation nor interest with them, just a satisfied customer (I own a few Henry's!) Good luck! ON EDIT: Sorry for the multiple edits. For some reason the Henry tube link wasn't working... My appologies. -- 73, ~Alan
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Re: 3-500 tubes
3-500zg orders placed through the Harbach site will almost always ship within one business day.
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And if an issue comes up, penta is quick to replace. As long as within the warranty Period, and the tube has not been abused. On 2024-05-18 16:27, Jim Strohm wrote:
All, |
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Re: 3-500 tubes
All,
I emailed Tom Rauch's company to ask about prices and availability on 3-500Zs and 572Bs. ? As it happens, I have a need for both, and Rauch has a rigorous incoming test procedure, and it's documented on his website. ?His website says that he checks email twice a day, so if he checks on Saturdays I may have an answer late today. ?I'll share what he says about getting tubes. ?? 73 Jim N6OTQ |
Glenn Gianino (W2ADX)
Alan - W5ARM