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Sylvania 12AX7 / JHS 12AX7 - long black plates, preamp grade

Sylvania JHS 12AX7 - long black plates
Price: $79.00
2 in stock
Item Number: 954BP
Manufacturer: Sylvania

This 1955 military spec Sylvania 12AX7 tube has long black plates with copper grid posts and a horseshoe getter. The green print on the glass reads "JHS 12AX7" (may be partial) and 12AX7 is etched in the glass.

This tube tests as new. It has been screened for gas, heater-cathode leakage, shorts, and excessive noise and microphonics on each triode section. It was tested at typical operating voltages on a laboratory grade Amplitrex AT1000 (manual setting, fixed bias mode). Learn more about our testing process here.

Noise and microphonics

This tube tests as “preamp grade”
on our custom noise testing equipment. It is an excellent choice for sensitive applications such as preamps.


This ships in a new white box with test results for current draw (mA) and transconductance (Gm) for each triode section.

TC Tubes specializes in precision testing and matching of vintage and new production vacuum tubes for guitar & bass players, audiophiles, and DIY tube audio enthusiasts. Our website features secure payment options and fast, convenient shipping around the world.

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