Vacuum Tube - 12AX7 / ECC83, Electro-Harmonix

Vacuum Tube - 12AX7 / ECC83, Electro-Harmonix

Electro-Harmonix
Pictured: Regular
Pictured: Regular
Pictured: Regular
Pictured: Regular
Pictured: Regular
Pictured: Regular
Pictured: Gold
Pictured: Gold
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Starting at: $27.95
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This Russian tube is full bodied and bright with a more straightforward presentation. It packs a lot of bite with its higher-than-normal gain. In overdrive, it offers a lot of crunchy fizz. High gain preamplifier tube with ultra low noise and detailed, musical tone. Unique spiral filament eliminates filament to cathode induced hum common on amplifiers that use AC on the filaments.

Superior high gain short plate format Twin Triode, with ultra-low noise and detailed, musical tone.

  • Ultra-low noise thanks to unique spiral filament which eliminates cathode-to-filament induced hum on certain amps
  • ECC83/7025 equivalent

For more information about our 12AX7 tubes, see our tech corner article on 12AX7s.

SKU:
T-12AX7EH
Item ID:
004458
Brand:
Electro-Harmonix
Part Numbers
Pin TypeOur Part NumberUPC/EAN
RegularT-12AX7EH683274020099
GoldT-12AX7-GOLD-EH841358101762
Product Measurements by Type
Amplification Factor78 min, 92 nominal
Capacitance, Cathode to Heater5.0 nF
Capacitance, Grid to Cathode1.6 pF
Capacitance, Grid to Heater1.6 pF
Capacitance, Plate to Cathode0.44 pF / 0.36 pF
Capacitance, Plate to Heater0.44 pF / 0.36 pF
Capacitance, Plate to Plate520 pF
Capacitance, grid to plate1.6 pF
Grid Circuit Resistance (Rg), Fixed Bias1 MΩ
Grid Circuit Resistance (Rg), Self Bias2.2 MΩ
Grid Reverse Current0.2 μA
Heater Voltage6.0 - 6.6 V / 12.0 - 13.2 V
Heater to Cathode Voltage, Negative200 V
Heater to Cathode Voltage, Positive100 V
Plate Current (Ia)9 mA
Plate Dissipation, per triode (Wa)1.0 W
Plate Resistance (Ra)54.1 kΩ
Plate Voltage (Ua)300 V
Transconductance (S)≥ 1.4 mA/V, 1.7 mA/V nominal
Packaging Information
Packaging DimensionsGold versionT-12AX7-GOLD-EH2.75 in. × 1 in. × 1 in.
Regular versionT-12AX7EH1.1 in. × 1.1 in. × 3.1 in.
Weight (Packaging)Gold versionT-12AX7-GOLD-EH0.035 lbs.
Regular versionT-12AX7EH0.038 lbs.
Product Measurements by Item
T-12AX7-GOLD-EH - Gold versionAmplification Factor78 min, 92 nominal
Capacitance, Cathode to Heater5.0 nF
Capacitance, Grid to Cathode1.6 pF
Capacitance, Grid to Heater1.6 pF
Capacitance, Plate to Cathode0.44 pF / 0.36 pF
Capacitance, Plate to Heater0.44 pF / 0.36 pF
Capacitance, Plate to Plate520 pF
Capacitance, grid to plate1.6 pF
Grid Circuit Resistance (Rg), Fixed Bias1 MΩ
Grid Circuit Resistance (Rg), Self Bias2.2 MΩ
Grid Reverse Current0.2 μA
Heater Voltage6.0 - 6.6 V / 12.0 - 13.2 V
Heater to Cathode Voltage, Negative200 V
Heater to Cathode Voltage, Positive100 V
Plate Current (Ia)9 mA
Plate Dissipation, per triode (Wa)1.0 W
Plate Resistance (Ra)54.1 kΩ
Plate Voltage (Ua)300 V
Transconductance (S)≥ 1.4 mA/V, 1.7 mA/V nominal
T-12AX7EH - Regular versionAmplification Factor78 min, 92 nominal
Capacitance, Cathode to Heater5.0 nF
Capacitance, Grid to Cathode1.6 pF
Capacitance, Grid to Heater1.6 pF
Capacitance, Plate to Cathode0.44 pF / 0.36 pF
Capacitance, Plate to Heater0.44 pF / 0.36 pF
Capacitance, Plate to Plate520 pF
Capacitance, grid to plate1.6 pF
Grid Circuit Resistance (Rg), Fixed Bias1 MΩ
Grid Circuit Resistance (Rg), Self Bias2.2 MΩ
Grid Reverse Current0.2 μA
Heater Voltage6.0 - 6.6 V / 12.0 - 13.2 V
Heater to Cathode Voltage, Negative200 V
Heater to Cathode Voltage, Positive100 V
Plate Current (Ia)9 mA
Plate Dissipation, per triode (Wa)1.0 W
Plate Resistance (Ra)54.1 kΩ
Plate Voltage (Ua)300 V
Transconductance (S)≥ 1.4 mA/V, 1.7 mA/V nominal

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Specifications, Files, and Documents

PDF: Specification Sheet Specification Sheet779.58 KB

Questions and Answers

Click each question to see its answers.
Asked by Anonymous on June 20th, 2017.
Matt H.
June 20th, 2017
Staff Member
It looks like your amp takes one 12AX7 and two 12AU7's. This Electro-harmonix 12AX7 will work and you can find the 12AU7 on our site.

Product Reviews

4.50 out of 5 based on 20 reviews
tom colopy - September 13th, 2022
5 out of 5

perfect!

clint - January 16th, 2022
4 out of 5

4.5 star

Anonymous - July 18th, 2021
5 out of 5

These are great sounding, reasonable tubes!

Paul L. - January 27th, 2021
5 out of 5

Excellent service and products!

John Bradford - June 25th, 2020
5 out of 5

Used in V1 in my Reeves 225, sounds excellent & can be recommended.

Kelly L. - May 20th, 2020
5 out of 5

Great price on a great product! Have always liked the Electro-Harmonix tubes and these sound exactly as described.

Mark O Matic - November 21st, 2019
5 out of 5

Replaced a standard 12AX7 with this tube to add a bit more gain in this 5 watt amp. Not a huge difference, but enough to notice.

Paul McIntire - October 26th, 2018
5 out of 5

Good Solid Tubes
Nice Tone

Mike P - September 8th, 2018
1 out of 5

For a Fender Deluxe Reverb, Out of a full set of Electro Harmonix tubes, just pulled out the last bad one. Out of 5 tubes, 2 12AT7's and 3 12AX7's, every single one was bad. The first shot, 2 extremely microphonic 12AX7's, since they were in the return period, AES sent replacements. The 12AT7 reverb driver blew out last week (probably less than 25 hours runtime), replaced that, then this week one side of the phase inverter dropped gain suddenly. Since they are now out of warranty, I had to replace 3 bad tubes out of pocket. Until Electro Harmonix fixes their quality problems, I would not recommend their 12AX7's or 12AT7's.

daryl stillman - August 12th, 2018
5 out of 5

best bang for the buck these little baby's work great in all applications, put them in high gain builds and they are awesome.

Substitute Products

The following items can be substituted for this product. While not necessarily exactly the same, they will function as replacement items in your project.