Mullard CV4004 / 12AX7

11 Reviews
SKU: MU-CV4004-12AX7

Availability: Usually ships within 24 hours.

USD $‎17.95
The new Mullard CV4004 / 12AX7 vacuum tube has a short plate construction making it more stable and better able to handle the vibration inside guitar combo amps.

From our review: "The smaller plates reduce noise. They are dead quiet both electrically and mechanically. Nice thick bottles and well aligned internals also help. If you currently like the Tung-Sol 12AX7 you will love this tube. The gain is similar but overall it is quieter and a bit warmer to my ears."

From the manufacturer: "The CV4004/12AX7 is a high gain, low noise valve with a short plate structure for reduced microphonics. Excellent for use in high gain Marshall pre-amplifier circuits where noise and microphonics can be a problem. Best for guitar amps."

The Mullard name and trademark have been acquired by the New Sensor Corporation. This new production Mullard CV4004 tube is manufactured at their Xpo-Pul factory (also known as Reflektor) in Saratov, Russia. New Sensor is an American corporation and since taking ownership of this factory has been steadily improving the quality of current production tubes.

Other Mullard tubes12AX7 Types

Additional Information and Downloads

Tube Matching Information:
Matched Sections Service

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

11 reviews

  • 3 stars
  • 0 reviews
  • 2 stars
  • 0 reviews
  • 1 star
  • 0 reviews

Great Tube!


I recent did a switch in my 1979 Marshall 2203 JMP amp which was a US model one with 6550s and had it modded to take el34s which I just bought the JJ E34L tubes here as well and I am happy with there sound as well. I play a lot of AC/DC so hence why I switched to El34s. I ordered one Mullard CV4004 12ax7 along with the power tubes to try something new. I currently have the mullard in V1 and it sounds great. I know a lot of sites say this tube is the highest gain 12ax7 you can get right now but that is far from true. This tube is an average gain tube which I think most people want but the thing I loved about it compared to a few others I tried in V1 was the tube is clear and warm with a bit of that fat cream to it. It didn't sound as brittle or harsh compared to a few other GT and JJs I have tried in V1 and it still packs a great punch. I would buy this tube again for sure!

Nice Valve


Used this as a replacement for a AVT 275. A whole lot less noise. Made for even nicer clean ranging from tweedy to voxy. A hair less gain on OD1&2= cutting down on the muddy OD 2. Which made for some sweet ZZ-tone with the treble cut out.

Excellent in Orange Rockerverb MKIII


Wow! Absolutely perfect tubes for this amp (clean and both dirty channel positions) and they sound fantastic! I'll be using these from now on. They are exactly the sound I have been looking for - smoother and much more full sounding than Tung-Sol's in these positions, without question.

Marshall + Mullard = Melodious

by -

I purchased a matched pair of these along with a matched and balanced quad set of Mullard CV4004/12AX7 tubes for my Marshall JCM602 combo, and after slightly adjusting the bias back to the referenced -42V I am very pleased. The clean channel sounds much better, i.e. the bass response is punchy and tight while the mids are well balanced, and the highs are sharp and crisp. In relation to the stock Svetlana tubes, the overdrive channel does lose just a tad of that trademark Marshall tone to my ears, but overall I consider the tradeoff to be well worth it.

The Goldilocks Zone for a VOX NT15H Finally Achieved

by -

I've gone down the rabbit hole with a Vox NT15H (v1), checking out just about every tube, every speaker that's easily accessible, and I finally feel as though I have this amp dialed in. (Contrary to what many might say, no matter what tubes or speaker used, it is very much like an AC15; and in its bright mode, it does wonderfully Voxish clean chime and top-boost crunch. In its thick mode, it also does a pretty good crunchy tweed-like thing -- with the wrong speaker, wrong tubes, it only gets about 75-85% of the way there, though -- with the wrong stuff, you can also achieve ice-pick highs and honky, cocked-wah-like mids, so I understand the mixed views on this amp). But with these CV4004s, Mullard's EL84s and an Alnico Blue or Weber Bluedog, I've finally found this amp's right stuff. She's finally in the proper Goldilocks zone. (For those curious, JJ's EL84s and 803S large-plate preamp valves were very close, coming in second place for me.)