Electro-Harmonix 12AX7

18 Reviews

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USD $‎29.95
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

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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

Love it!


I am a hobbyist without much experience regarding different tubes so I can only say that I replaced the stock Chinese tube with this EH 12AX7 in my Gretsch G5222 and I immediately noticed a difference. Overall just clearer in both low end and high end and louder but I also replaced the Chinese 6V6 with the TAD 6V6 at the same time! So which tube improved the sound dramatically...well both! The stock speaker is still not great but both these tubes already make my amp sound 70 % better!

Best option for the price!


Have used several different pre-amp tubes, JJ, Tung-Sol, Mullard, Sovtek and in this price range I tend to always fall back on the EHX 12AX7. Never had an issue with noise or microphonics. I've dropped them and still never had a problem. They last and sound great, nice harmonics and crunch without being fizzy or dull. I haven't noticed a difference I can pin-point between the regular and gold pin tubes, but I suppose the gold pins are good if the rest of your amps connections are gold plated.



Swapped out some older JJ tubes in a pre-amp feeding a Parasound power amp. These seem to require a bit more warm up, and seem clearer on the bass than the JJ tubes. That's not a bad thing, as I think the highs are equally crispier through my AR speakers I can echo one of the other reviewers, they just seem louder all around. All in all, I'm impressed for the price. I wish I wouldn't have waited so long to change them out.

My two cents


This preamp tube sounds very clear and nice but it has no low end at all. At least not for me. Stuff this in your amp if you have too much low end and want to balance it out, that is my recommendation.



I agree with the comments posted. I switched them into my 1987x after I dropped the bright cap down to a 400pf. I also coupled them with Mullard EL34's for the output. I use OD's with this amp so I can run it at moderate volume. It is a beautiful, bell like, crisp and punchy well articulated tone machine. I'm a EH12AX7 fan all the way.