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All ye experienced tube folks, explain me this
morzh
Odobenus rosmarus
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Posts: 16,507
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City: Jackson State, Province, Country: NJ
#1

11-04-2016, 08:47 PM
This week first I tested KT88 on my Hickok 600 and they are fine.
These are Russian made.

Today I decided to check 12AX7 and 12AT7. All tubes marked as Mac, all are Chinese.

Q1. The very first 12AX7 tube I tested first goes very bright for a split sec, then goes normal. Tests good. The rest of the 7 tubes do not do that, they go to normal glow, no flash.
Why?

Q2. All four 12AT7 test 1700-1900 at 4500 table value. Is this normal or...?
Q3. All tubes when tested for gas, exibit large (1 full division) needle movement only when the 1st triode is being tested. The second only moves the needle by 1/4 div. Why?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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All ye experienced tube folks, explain me this - by morzh - 11-04-2016, 08:47 PM



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  1. The PHILCO Phorum
  2. Various and Sundry Categories
  3. Vintage Hi-Fi, Stereo and Audio