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RE: Did I miss any of the 12AX7 replacements?

12BZ7 doesn't have higher gain - it has higher transconductance but gain (mu or amplification factor) is 100, same as 12AX7. They are reputed to be quite microphonic, watch out for that. Heater current is twice that of a 12AX7, so it can't be used in a series circuit (as in a Fisher amp or receiver, DC preamp heaters in series). Conversely, the 7058, with no heater tap, can't run at 6.3V but will work fine in a series circuit. (some 7058s DO have the tap connection, though it's not on the data sheet.)


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  • RE: Did I miss any of the 12AX7 replacements? - Tom Bavis 12:14:56 09/02/14 (0)

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