| Identical gain & tonality in double-triode tubes (ECC82) [message #94909] |
Mon, 13 December 2021 10:52  |
kasperbergholt
Messages: 44
Registered: August 2021
Location: Copenhagen, Denmark
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Baron |
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Dear tablers,
Inspired by the excellent feedback (e.g. on the E80 CC tube having quite different specs from the ECC82) the I got in this thread:
https://audioroundtable.com/forum/index.php?t=msg&th=23320&goto=94872&
some new questions have shown up in regards to gain levels for a single tube preamplifier like mine.
Which parameters determine the level og gain?
Some measurements are extremely detailed, e.g. this one from an eBay listing:
Sollwert IA [mA] fx 10,5 og 10,5
Messwert IA [mA] fx 10,012 og 9,945
= % vom Sollwer 95 og 95%
S (mA/V] 1,92 og 19,96
bei Deltage UG1 0,6 og 0m6
D Anode [%] 6 og 6,1
Messwer IA [mA] 7,2 og 7,13
bei UA [V] 225,08 og 225,08
Ri [KOhm] 9,1 og 9
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A different listing for a tube in the same price range is a lot more sparse:
ECC82 TELEFUNKEN ( 12AU7 E82CC CV400 ) # <> # NOS
gemessen auf RPM370
12 / 12 mA 100 % = 10,5 mA
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Most list the mA values, few the Anode value.
In addition, is there a formula for calculating if the difference between values will be noticable e.g. in a 1 dB's difference in volume measured from 1 meter from the loudspeaker?
And, lastly, how about differences in tonality / frequency response. Are such inherent in the gains measurement (or other parameters)?
Thanks again,
Kasper
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