W9ZSL
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« on: February 10, 2016, 09:14:12 PM » |
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I found a matched pair of 811A Machlett tubes for my mudulator. Any comments on the brand?
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KD6VXI
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Making AM GREAT Again!
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« Reply #1 on: February 10, 2016, 10:46:19 PM » |
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Ever since Eimac got out of glass, Machlette has been an rf parts brand.
Taylor
Machlette
Blah blah blah.....
--Shane
KD6VXI
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W9ZSL
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« Reply #2 on: February 10, 2016, 10:54:02 PM » |
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Is that good or bad?
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W7TFO
WTF-OVER in 7 land Dennis
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IN A TRIODE NO ONE CAN HEAR YOUR SCREEN
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« Reply #3 on: February 11, 2016, 02:06:45 AM » |
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The real Machlett got out of the tube biz a long time ago, maybe 'cept for X-ray stuff.
Now made in China, just like the 'new' Taylor tubes.
A warranty is one thing, crappy emission down the road is another.
I'd search hard for good NOS stuff with a return if bad. Those will last.
They are out there...but not cheap.
73DG
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Just pacing the Farady cage...
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PA0NVD
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Nico and Chappie (Chappie is the dog...)
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« Reply #4 on: February 11, 2016, 07:20:07 AM » |
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I used many Chinese tubes bought from Phamitec. Low cost and no problems. A bad tube was replaced free of charge directly. But that were 6, 10 and 25 kW tubes. But I also bought smaller ones for linear amps for radio hams. Again without problems. They seem quite good to me.
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W9ZSL
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« Reply #5 on: February 11, 2016, 12:57:58 PM » |
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How about Soviet brands?
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W7TFO
WTF-OVER in 7 land Dennis
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IN A TRIODE NO ONE CAN HEAR YOUR SCREEN
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« Reply #6 on: February 11, 2016, 02:05:10 PM » |
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The Russians know how.
So did we:
eBay 182017549679, 262241121591
73DG
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Just pacing the Farady cage...
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W9ZSL
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« Reply #7 on: February 11, 2016, 02:22:30 PM » |
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Will check them out; thanks! I do have one tube already BUT I'm not sure if it is an "A" because the number is on the base and the numbers fade. It has two small numbers to the left,one (59) above the other (42). The label reads JAN-CD7-811 and possibly "A" made in USA; Electronic Enterprises, Inc. which seems to be a distributor not manufacturer. It appears NOS and the plate has no discoloration what-so-ever.
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w1vtp
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« Reply #8 on: February 11, 2016, 05:10:27 PM » |
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In the not too distant future, we are all going to have to suck it in and move on from the 811(&a) and find another tube of like performance. 572B's work in some instances plus the plate dissipation is greater. I'm going to stuff my EFJ Courier with 572B's next time I have to retube. The current 811's are junk in my opinion.
If you are talking NOS, 811's without the fins on the plates are plain-Jane WW2 variety. The ones with the fins that are in good shape should be considered gold-plated. I suggest we just look for a good pair of 572B's when at all feasible.
Al
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W9ZSL
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« Reply #9 on: February 11, 2016, 05:34:42 PM » |
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Right Al. So who makes the best 572B??? The attractive thing about using those is I can go back to a single supply up to 2 KV and neither the 813 or the 572Bs should mind. I found an RCA with fins and am bidding on it. However, planning ahead, next question. I have both conventional 4-pin ceramic sockets and this locking type which I prefer. Will a 572B fit?
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w1vtp
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« Reply #10 on: February 11, 2016, 10:43:09 PM » |
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Right Al. So who makes the best 572B??? The attractive thing about using those is I can go back to a single supply up to 2 KV and neither the 813 or the 572Bs should mind. I found an RCA with fins and am bidding on it. However, planning ahead, next question. I have both conventional 4-pin ceramic sockets and this locking type which I prefer. Will a 572B fit?
I'm not up to the latest on 572's. I recall a discussion on this on forum. And yes you should substitute 811s with 572s. Not sure about using the locking type socket if you don't have the pin on the base |
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W9ZSL
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« Reply #11 on: February 11, 2016, 10:52:49 PM » |
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I managed to score a nice JAN RCA bottle that matches the one I have for $37.00 plus shipping. I'll go with the big sockets. Since only the mod iron, filament iron and the tubes will be mounted on a relatively small chassis with a 300 MA meter on the front panel, reconfiguration should be easy. Got to do it because the project has been on hold long enough. The build should be quick and easy. Will post photos. Thanks!
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