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
Click to zoom in
Pictured: RegularPictured: RegularPictured: RegularPictured: Gold
Customer Images:
No Images yet! Submit a product image below!
Starting at: $13.95
Product Options
  • Regular (T-12AX7EH)
are currently out of stock and will be placed on backorder. This product has substitutes available! Check them out.
Please log in or register to receive an email when this item is back in stock.

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

My Project Lists

You must be logged in to add items to a project list.

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 18 reviews
- July 18th, 2021
5 out of 5

These are great sounding, reasonable tubes!

- January 27th, 2021
5 out of 5

Excellent service and products!

- June 25th, 2020
5 out of 5

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

- 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.

- 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.

- October 26th, 2018
5 out of 5

Good Solid Tubes
Nice Tone

- 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.

- 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.

- July 22nd, 2018
5 out of 5

I start a copy of an EC3 audio research crossover who needs 12 12AX7. During the testing phase i use some cheap and classical EH. Then I tested with my NOS AN GE of 1960 inherited from an old radar repair and kept in a safe ... No significant difference, except perhaps in the dispersion of the characteristics.
Thanks a lot for the quick service.

- August 26th, 2017
5 out of 5

I have a Marshall TSL602 and had a Mullard reissue 12ax7, cleans up very nicely, go out on V1 so I tried replacing it with what I had in my stock. I tried the EHX 12ax7 and found it to have alot of distortion on tap, very crunchy fizzy. This is good for my lead channel but the crunch channel had to be set to too much preamp to get it to sound natural, too much fizz and not enough crunch and ended up almost as distorted as the lead channel. The clean channel was something else entirely, the just starting to breakup crunch that the Mullard had was fizzy and not natural sounding. I took it out and settled on a Tung Sol 12ax7, better all around tube.