Loading... Please wait...Mullard CV4024/12AT7 - These are in Royal Air Force boxes, made in Great Britain, and are WONDERFUL. Each tube wrapped with a cardboard inner liner and pin protector. This is the most popular and sought after 12AT7 ever.
Super popular for VTL, Manley, Atma-Sphere, and others. Why? They were made better. Compared to the earlier Mullard with the folded plate these consistently last longer, have a tighter triode balance, and are quieter. Just because they are not crazy expensive at the present moment don't let that fool you. Higher price does not always mean better quality when it comes to new old stock.tubes. It means rarer. And that means maybe they didn't make that many in the first place. This tube was standard issue to NATO forces around the world, and now that the Cold War is over we reap the benefits. But they will go up, just like the Mullard CV4004/12AX7 went up. So party on.
Platinum grade - The best of the best. Lowest noise and microphony with the tightest triode balance we have available. This is typically 10% or tighter, but may be higher depending on available stock.
Gold grade - Low noise and microphonics with a triode balance typically between 15% and 20%, but may be higher depending on available stock.
Driver grade - Lowest noise but not the lowest in microphony. Triode balance will be similar to Gold grade.
This grade is only suitable for use in the driver stage of an amplifier, or the output/buffer stage of a DAC or CD Player.
If you have a preamp or phonostage, you need at least Gold grade
Click here for a more in depth discussion on how we grade tubes.
Posted by Paulie
Sweet in guitar amps. Rocks!
Posted by Paul
Kevin is not into guitar amp guys, but I must say that''s he''s done OK by me. That said, the Mullard CV4024/12AT7 has proven to be extremely tasty in the PI of certain blackface guitar amps. I have found that it is not a shoe-in for all amps, but with certain ones, it makes the difference between good, and damned tasty.
Posted by Roger
I have RCA, Sylvania Gold Brand, RCA, Telefunken, Amperex Holland, and the earlier Mullard that look just like the Amperex Holland (same looking guts inside).
The CV4024 are my clear favorite, being quieter and letting inner detail emerge from a black background on my VTL. I bought another pair as the price is so good and I know at some point they will be as expensive as the CV4004/12AX7.
I don't mind spending the money but if something is a great buy I'm behind that. The military boxes are neat to look at.
Most of you already know that Upscale Audio is the premier destination for expertise and availability of vacuum tubes for high-end audio equipment. So when we offer servies and options, you can be guaranteed that it represents a significant investment of research and capital, and that the end result will greatly enhance your listening experience.
Upscale has contracted with the foremost company involved in this technology, 300 Below, to treat our most popular tubes. Other tubes will be added as time allows, but it is a time consuming proccess. Our intention is to have most stocks Cryogenically treated before we even test them.

Of course, your first question is – and should be – why? In a nutshell, reducing an object’s temperature to -300ºF re-arranges its molecular structure, creating greater uniformity that results in longer life and better performance than when the product was initially designed.With vacuum tubes, this process has a profound impact on a tube’s ability to endure thermal shock. Therefore, tubes can last longer and their sound can been enhanced in ways that are simply exquisite.
After thoughtful and thorough research, Upscale Audio chose 300 Below because of their extensive experience in working with musical instruments as well as auto racing, metal tooling, and high-end sporting goods from rifle barrels to golf clubs. Expect nothing but the best from Upscale Audio.
Our charge for Cryogenically treating tubes is a fraction of what others charge, though we use the premier company. Count on Upscale to do the best job and not price gouge . Also available is cryogenic treatment for cables, along with our well-known Nordost Vidar cable treatment system. Call for details. Pricing is listed on each tube and cable page.
Vacuum tubes are warranted for 90 days against defects, except in cases of abuse, and replaced with like-item only.
Exceptions to our warranty policy are as follows:
Upscale Audio is not liable for any damage or injury caused by the improper use of its tubes or the use of an incorrect/incompatible tube type. If you are unsure of what tube or tubes your equipment uses, consult the manufacturer before making a purchase. Using an incompatible tube type may cause severe damage to your equipment and will void your tube's warranty.
Vacuum tubes are electronic parts and are not refundable under any circumstances.