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Old 14th July 2013, 02:25 PM   #11
hpeter is offline hpeter  Europe
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they put S even on rectifiers..
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Old 14th July 2013, 04:54 PM   #12
Gost22 is offline Gost22  Bolivia
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Why?
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Old 14th July 2013, 05:37 PM   #13
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Because the company is run by shady persons. And because they need to keep up sales or they go out of business.

Remember an EL34 would have cost something like 100 modern euros back in the 60s


Anyway watering of type designations is not something new.
For instance Tungsgram produced alot of tubes thay had a T before the name E.G. TAL4

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Old 15th July 2013, 05:05 PM   #14
hpeter is offline hpeter  Europe
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...or run by marketing wizards
sad

i think, one part of success recipe is to make tubes on vintage equipment. they have it.
but that´s not whole story.

they should have the balls to develop advanced tube versions, for example like chinese are doing graphite versions of 300b.
how about revival 100,250TL ???
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Old 15th July 2013, 06:12 PM   #15
kruesi is offline kruesi  United States
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Still, they produce pretty darn good tubes, especially the small-signal types. I've had issues (short life, build quality) with their octal types, but IMHO their 7- and 9-pin types are Things of Beauty. I'm especially fond of their 12AX7 with the spiral heater. Letters and designators notwithstanding, these are great tubes at a good price.
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Old 16th July 2013, 02:31 AM   #16
aliwang is offline aliwang  Hong Kong
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many thanks!
My mean is not going to compare which brand is good or not, I'm just wish to select good tubes from hundreds of tubes. So, my concern is these values ​​must be controlled to what extent?
IP Emission
GM
H-K Leakage
Gas
Noise

Also, I think a good tube requires a good sound quality, also need to have a long life and good price.
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Old 16th July 2013, 07:35 AM   #17
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It all depends on context. How long is a piece of string? It depends on what you want the string to do.
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Old 16th July 2013, 10:00 AM   #18
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Quote:
Originally Posted by aliwang View Post
...I think a good tube requires a good sound quality...
I wonder what could be the reason that the manufacturers have never mentioned anything about this feature in the tube data ??
Could it be so that this does not exist ?
Or if it exist, is it not controllable by the manufacturers ?
Still it seems to be most important for so many diyers.
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Old 17th July 2013, 03:25 AM   #19
aliwang is offline aliwang  Hong Kong
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I found a page to introduce how to select 12ax7, unfortunately, which only mentioned the Ip meas and GM, other items not mentioned.
How to select 12AX7

Last edited by aliwang; 17th July 2013 at 03:51 AM.
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Old 17th July 2013, 09:12 AM   #20
DF96 is online now DF96  England
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That page is about testing for faulty ones (worn out or badly made). It won't tell you about sound, but no ordinary test will tell you about sound. A good circuit will work well with almost any non-faulty valve - with the exception of noise and microphony. A bad circuit may need valves with a particular type of characteristic - perhaps similar to the ones used when the circuit was 'designed'.
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