Electro-Harmonix 12AX7

18 Reviews

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USD $‎29.95 USD $‎26.96
1 +USD $‎29.95
1 – 99USD $‎26.96
From our review of this tube: "The EH-12AX7 tube has a nice balanced sound, a very low noise floor and excellent performance in terms of microphonics. The lack of microphonics may be due in part to the return of a shorter plate structure or better materials. I've had some samples that were tried in various amp stages. Pre-amps, tone stacks and phase inverters, a winner in every location...I have used the EH to successfully tame amps that defied all other attempts to kill microphonics and unwanted feedback. This tube is a winner, buy 'em and try 'em, they may be just the piece you've been looking for."

One other note about the construction of these Electro Harmonix 12AX7 tubes is they have filaments that are almost completely encased in the plate structure. They often don't "light up" when working properly. This is not a problem, it's normal for the 12AX7-EH.

Other Electro-Harmonix tubes12AX7 Types

Additional Information and Downloads

12AX7 Tube Review

Tube Matching Information:
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Electro-Harmonix 12AX7-EH Datasheet (PDF)

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Warranty Information and Return Policy

Warranty Period: 3 months

All our tubes are guaranteed for 3 months from the date of purchase. (Any exceptions will be noted on that tube's Warranty tab)

If you receive a tube that does not perform to the manufacturer's specifications, please do the following:

- contact us to get a return authorization
- return it via regular mail within 90 days from when we shipped it, and we will provide an exchange or refund of the full purchase price of the tube.

Returns not related to warranty or defect will be considered at our discretion, and are subject to a 15% restocking fee.

We can not accept returns that don't have an authorization, are past 3 month, or are returned improperly.

These guidelines may be updated without notice.

Ratings & Reviews

18 reviews

My surprise favorite


Experimenting with the sovteks, chinese, TAD, and whatever Boogie and Groove Tubes ship, these are my favorite. At this great price, they are my favorite by far! (Though I do not know the high end $50+ stuff in this segment).

At first I was wary of the New Sensor branding (was it going to just be a Sovtek?) but after A/Bing, this is almost all I use now. No noise issues, and a good, fairly well balanced tone that can produce plenty of gain without drastic effects on headroom.

A survey of my active amps shows that I have nine of these in use now . . . and only two of anything else (soon to be replaced by either something I've never tried before, or these). Whether the amp has 5 12ax7s or just one I have had success with these.

Crisp Modern Sound


These are my 2nd favourite new production russian 12ax7 (1st being the TungSol). They're quite detailed, maybe a hair less than the Tung Sols, but unlike the Tung Sols, are much more crisp sounding, and have more of a tight crunch to them with some gain. Low microphonics, and seemingly good build quality. I use one in the EQ/Loop stage of my amp. Good for brightening up darker amps.

worth changing


Put these in a Marshall DSL 15 in V1 & V2
much more musical and harmonically rich than the JJ ECC83S tubes. Research and warmth ratings said JJ's were the rite choice for this bright mid-rangey amp
but these made a great improvement. Tried JJs in 2 spots then all 4 spots and just got to noisy and lost character
now running 2x EH's and 2 stock Shuguang and it's great. Amps now capable of classic vintage rock and hi-gain metal and lets the guitar choice shine through more.

Great !


I like these better than Telefunken smooth plates. Less high order harmonics, nice clean sound in a 6V6 push pull amp I tried them in.

Well balance tubes..


I put these in my Tubemeister 18 head and all I can say is Wow...these tubes are very well balance...way more detailed and musically rich...better than these Tungsol tubes...