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Author Topic: China Made 3cx800a7, any good  (Read 2535 times)
KE2TR
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Posts: 155




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« on: August 30, 2014, 07:49:48 PM »

Has any one purchased and used the Chinese made 3xc800a7's for there amp's? I know a few years back the 8877's were not so bad but do remember W8JI saying something about the 800's not being so good coming from China and for a while Ameritron offers the import tubes in there amp's at a very nice savings over the Eimac's plus RF concepts sells them as well for about $400. Anyone out there use these new import tubes yet and maybe care to comment on there results.
Jim
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W3RSW
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Posts: 127




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« Reply #1 on: August 31, 2014, 06:18:03 AM »

I too am interested in the long term reliability of 3cx800's from RF Concepts' supplier. There are some interesting notes about the usefulness of these in Alpha's legacy amplifiers requiring a low grid intercept pair.

http://www.rfconcepts.com/PRODUCTS/tubes/3CX800A7-Tube-FAC-Triode-Low-Grid-Current

Time will tell.

Apparently they are good enough to meet Eimac's original specs. Since RF concepts mentions that they're good for the Alpha 89, etc. running 2250 to 2500 Vdc Ep loaded.
http://www.g8wrb.org/data/Eimac/3CX800A7-Preliminary-March-1983.pdf
« Last Edit: August 31, 2014, 06:24:08 AM by W3RSW » Logged
NM6V
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Posts: 79




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« Reply #2 on: August 31, 2014, 07:59:32 AM »

I don't see it mentioning anything about using them in a Alpha 86 which I have.
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W3RSW
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Posts: 127




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« Reply #3 on: August 31, 2014, 08:07:27 AM »

Your 86 is manually tuned, not subject to the auto-hunting limits of the 87 mentioned in Alpha's note.
Should work ok with the RF Concepts tubes.
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AA4HA
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Posts: 1450




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« Reply #4 on: August 31, 2014, 11:21:52 AM »

It does not matter who the distributor is, they all roll off of the same production line in some factory in China. Things over there get re-branded and swapped from wholesaler to wholesaler, to warehouses and back to resellers and distributors. Figuring out exactly who made the tube and when will be about as easy as verifying the existence of bigfoot.

For a while there were substantial quality issues with some of the tubes. Internal tolerances, trace contaminants and substandard assembly techniques all contribute to a poor track record on some tubes. The problem is that you can never tell if you got a good tube until you can put it under power for a certain amount of time. Even then those trace contaminants begin to leach out as the tube is under power and can poison the internals (conductors or ceramic surface).

Even Eimac had problems at one time but they were a bit better about 'fessing-up to their problems and replacing the bad units. With an overseas manufacturer you are only going to be able to get as far back up the food chain as the retailer who sold the tube to you. Some of the local importer/suppliers consider that a certain percentage of returns are the cost of doing business and may be a bit more accommodating in taking back a bad tube. Do not expect anyone to honor any sort of return policy on a tube that has been out there for more than a few weeks or months.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
N1UK
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Posts: 1456




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« Reply #5 on: August 31, 2014, 04:10:43 PM »

I had a Matchlett 3CX800A7 which failed after 11 months of the 12 month warranty period and the company honoured the warranty and sent me a new replacement tube free of charge, this year.


Mark N1UK
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KD8MJR
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Posts: 2353




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« Reply #6 on: September 01, 2014, 01:35:12 AM »

Wow your lucky! If that had been me it would have died on the 13th month.
I have that kind of luck with warranties Smiley

None the less 11 months is dismal! That would not install a whole lot of confidece in me to buy one.
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KK5DR
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Posts: 71


WWW

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« Reply #7 on: September 06, 2014, 07:37:16 AM »

Nothing made in China is any good! Its all crap!
I deal with industrial parts made in China every day, and it's all cheap, junk, crap!
You get what you pay for.
Pay more, get American made, and it will last and be reliable.
If you buy cheap Chinese made tubes, get a bunch of them, your gonna need them.

Matt KK5DR (All EIMAC, all the time)
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N1UK
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Posts: 1456




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« Reply #8 on: September 06, 2014, 07:34:41 PM »

Unfortunately there is often little choice these days as very little is made in the USA, so all that is available is Chinese junk.

I won't bore you with my horror stories of Chinese junk. I am sure that we all have a bunch of our own horror stories to tell.

I miss the days when I could easily find and buy quality products.


Mark N1UK
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W8JX
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Posts: 5877




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« Reply #9 on: September 07, 2014, 04:58:11 AM »

Unfortunately there is often little choice these days as very little is made in the USA, so all that is available is Chinese junk.

I won't bore you with my horror stories of Chinese junk. I am sure that we all have a bunch of our own horror stories to tell.

I miss the days when I could easily find and buy quality products.


Mark N1UK

I do not doubt that some have had trouble but I have not and to say all chinese is junk is wrong. I have  seen some American junk in my time too.
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W9AC
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Posts: 58




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« Reply #10 on: September 12, 2014, 06:56:36 AM »

I had a Matchlett 3CX800A7 which failed after 11 months of the 12 month warranty period and the company honoured the warranty and sent me a new replacement tube free of charge, this year.

Mark N1UK

Real Machlett tubes were produced in Stamford, CT back in the '50s and '60s.  They manufactured power tubes that even Eimac was too timid to produce like this series:

http://72.52.250.47/images/Machlett-669x.pdf

It's painful to see the Machlett name being stamped on imported Asian product.

Paul, W9AC
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W8JX
Member

Posts: 5877




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« Reply #11 on: September 12, 2014, 09:43:45 AM »

It's painful to see the Machlett name being stamped on imported Asian product.

Would it be more painful to not see tubes at all? I know Chinese tubes can have quality issues but it is a obsolete technology and we need to be glad they still make them at all. Not cost effective to build them here.
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N6PJB
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Posts: 12




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« Reply #12 on: September 12, 2014, 10:57:52 AM »

I have been very pleased with my Matchlett stamped 3-500ZG tubes made in China.  Grin Grin
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W9AC
Member

Posts: 58




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« Reply #13 on: September 12, 2014, 11:30:37 AM »

It's painful to see the Machlett name being stamped on imported Asian product.

Would it be more painful to not see tubes at all? I know Chinese tubes can have quality issues but it is a obsolete technology and we need to be glad they still make them at all. Not cost effective to build them here.

Would you have a problem with a Chinese manufacturer selling 3CX800s under the Eimac brand name without CPII's authorization?  What if Eimac stopped selling them all together and the only place to source a 3CX800 is through China?  Using your logic, that would be acceptable under those conditions.  

Unless there was an intellectual property transfer, the Chinese Machlett company is misrepresenting itself as the original Machlett-USA when the name and logo remains exactly the same -- and even if the original Machlett company is no longer selling here.   

Paul, W9AC
« Last Edit: September 12, 2014, 11:59:49 AM by W9AC » Logged
W8JX
Member

Posts: 5877




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« Reply #14 on: September 12, 2014, 12:52:14 PM »

It's painful to see the Machlett name being stamped on imported Asian product.

Would it be more painful to not see tubes at all? I know Chinese tubes can have quality issues but it is a obsolete technology and we need to be glad they still make them at all. Not cost effective to build them here.

Would you have a problem with a Chinese manufacturer selling 3CX800s under the Eimac brand name without CPII's authorization?  What if Eimac stopped selling them all together and the only place to source a 3CX800 is through China?  Using your logic, that would be acceptable under those conditions.  

Unless there was an intellectual property transfer, the Chinese Machlett company is misrepresenting itself as the original Machlett-USA when the name and logo remains exactly the same -- and even if the original Machlett company is no longer selling here.   

Paul, W9AC

If you own rights to name you can make them anywhere you want. Pretty much everything is made in China these days due to low labor and raw materials costs. Not sure why you are getting all twisted up over tubes that are made there because it does keep prices down. Maybe you would like to pay 800 for a 3-500 or 400 for a new 572. Not me. I have no issues with using even import ceramic tubes.
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