| Author |
Message |
    
67gto
| | Posted on Sunday, September 14, 2003 - 12:25 pm: | 
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Hello Again,
Could someone please tell me what does it mean when someone is selling a matched pair of tubes or pills.
I asked a local on the air and they said it means that they bought them together.
I think it means more then that.
THANKS,
G T O |
Cobra0020
| | Posted on Sunday, September 14, 2003 - 1:18 pm: |
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Gto,
A Matched Pair is when the Tubes are the same Brand And At the Same Percent. Ex.. Rca 80% Then you want a matched pair so you get another Rca 80%. Atleast I Always thought this was what it mint
Cobra0020 |
Crafter
| | Posted on Sunday, September 14, 2003 - 2:13 pm: |
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Displace the same amount of current as the other. Man that sounds SMART huh. LOL. Ya means they put out the same power twins so to speak. |
Kc0gxz
| | Posted on Monday, September 15, 2003 - 1:37 am: |
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67gto
Matching is done when resistance is found to be closely matched between the pair of new solid state devices or vacume tubes.
Matching really doesn't amount to a hill of beans anyways because they are all mass produced and all of them have to fall within a certain tolerance anyways. Selling a pair of matched devices is another way of wringing more money out of you.
Don't think for one minute that these dual final 10 meter radios or even amplifier companys are going to spend the extra time find and put matched" pairs of RF devices in their radios or amplifiers. Their goal is to get these hammered together as quickly as possible and get them to market. As long as tubes and RF power devices are within a specified tolerance, that's all that matters. Besides, you would NEVER know or see the minute difference between a mismatched or matched pair anyways.
Tolerances are not that critical. A person could spend days trying to find a perfectly/exactly matched pair. If there is a resistance difference by as little as a 1/4 Ohm, then in reality, they're not matched.
Usually tubes and solid state devices do not wear or start to break down at the same rate. For example, you could put a brand new "matched" pair of 3-500Zs in an amplifier and after a year of very hard use, you may see when testing them that one of them may be at 70% of its rated power and the other may be at 45%. Oh Oh. Now what do you do?
The above statements are only my personal opinions and experiences with "matched pairs". I have learned over the years not to get very serious when it comes to pairing. I could NEVER see the difference in performance. I'm sure you are going to see other opinions posted here also.
73s
Jeff, kc0gxz. |
frasiercrane
| | Posted on Monday, September 15, 2003 - 1:51 pm: |
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Matched pairs are pairs that are selected to have similar characteristics, such as gain. It's probably more useful in tube audio amps to have them matched so you get lower distortion than it is in RF amps. The main reason for matching them in an RF amp is so that each transistor/tube shares an equal part of the load to keep one from getting over stressed and failing prematurely.
It might not make much difference, but if the price isn't much more it couldn't hurt to go with the matched ones |
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