Electro-Harmonix 12AX7 Preamp Vacuum Tube
From our review of the Electro-Harmonix 12AX7 vacuum tube: "The EH-12AX7 preamp 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 tubes
12AX7 TypesAdditional Information and Downloads
Reviews:
12AX7 Tube Review
Tube Matching Information:
Matched Sections Service
Downloads:
Electro-Harmonix 12AX7-EH Datasheet (PDF)
Download Adobe Acrobat PDF reader
Warranty Information and Return Policy
Warranty Period: 3 monthsAll 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
treble sensitivity
by Roy C
I have used a bunch of these eh 12ax7 tubes from time to time and recently tried them in a 65 twin reverb reissue. I realized that they can be a bit harsh in the treble on these already treble oriented amps. In my jcm900 dual reverb 100watt they sound amazing and is what they recommend as a premium upgrade for the preamp section. All in all they are an excellent and affordable replacement preamp tube but I would steer away from using them in bright fender-like amps, especially if you want to warm up the tone slightly.
Perfect For My Fender Super Champ!
by Mike W.
I used this in my Fender Super Champ as a replacement for the original Groove Tubes 12AX7, and I'm delighted with the sound. I'm using it along with a matched pair of JJ 6V6S amplifier tubes, and the sound is much warmer and full-bodied. Much better lows. I like it so much, I just ordered a spare :-)
We have a winner!
by Tony
I was looking to replace the original Groove Tubes 12AX7 R3 in my Carvin BX500 head and was having no luck with about 3 other tubes I tried. Finally I put one of these Electro-Harmonix tubes in and wow! Powerful, punchy bass again!
Neil
by Neil
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.
My two cents
by someone that is not a cuckservative
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.