the ultimate guide to tube-rolling: 12AX7

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The 12ax7 / ecc83

These are miniature dual triodes with a high voltage gain, commonly used in preamplifiers. They are still in production, made by New Sensor in Russia, Shuguang and Quanzhen in China, and JJ Electronic in Slovakia.

Tung-Sol 12AX7

Low noise and microphonics, but if you have a really high-gain phonostage, or want a more relaxed top end, the Mullard would be a better choice. Gorgeous mids, great dynamics, and a nice 3D soundstage.


Customer reviews 

Customers rate this tube very highly, with reviews praising a “clean” sound with good bass, and a “great top end”. Reviews also point out “3D imaging”, great detail, and overall huge value for money. 


Fun fact

The filaments are almost completely encased, so these won’t glow as brightly as other 12AX7s.

Mullard 12AX7

Very low noise and microphony, so this tube is well suited to touchy preamps and high-gain phonostages. Smooth midrange similar to NOS Mullards, but not quite the same. They are more relaxed on top, so a good choice for bright systems you want to tame. If you want more a more energetic presentation, consider the Tung-Sol 12AX7. 


Customer reviews 

All indications are that these are a worthy alternative to the expensive NOS version of this tube. Reviews talk about smooth mids but with detail and good bass. Customers who found their systems harsh or edgy, loved what these did to the sound. Sweetness, naturalness, quietness, tight bass, good soundstage are words that come up again and again. One caveat is, if your system is laidback, these might make it too dark. 

PrimaLuna 12AX7

PrimaLuna 12AX7
$29.95

One of the stock tubes for PrimaLuna EVO 100, ProLogue Classic, and earlier ProLogue products with a preamplifier stage. Made to a high spec for PrimaLuna by Shuguang in China, this is a quiet, reliable tube that does everything well, and is offered at Platinum grade.

Tung-Sol 12AX7 / ECC803-S Gold Pin

Tung-Sol 12AX7 / ECC803-S Gold Pin
$29.95

Some customers report that the gold pins are smoother, and with a bigger soundstage than the regular version (above), and offer a more refined sound. Otherwise, they are very similar to the original.Low noise and microphonics, but if you have a really high-gain phonostage, or want a more relaxed top end, the Mullard would be a better choice. Gorgeous mids, great dynamics, and a nice 3D soundstage. 


Fun fact

The filaments are almost completely encased, so these won’t glow as brightly as other 12AX7s.

Mullard New Production CV4004 / 12AX7

Mullard New Production CV4004 / 12AX7
$29.95

This 12AX7 is a reissue of the famous Mullard CV4004, hence the double-moniker. It is a short-plate version of New Sensor’s excellent Mullard 12AX7, and is reported to be even quieter, so this is the solution for a touchy preamp or high-gain phonostage. Like the long plate, it has a smooth, warm midrange, and is a little relaxed on top. 


Customer reviews 

This tube is warm, yet crisp and clear, and customers suggest this is a good way to add life to a sterile-sounding system by adding warmth without losing top-end detail. This is a good way for brass instruments to have body and warmth and keep their bite. 

Gold Lion ECC83 / B759 / 12AX7

Gold Lion ECC83 / B759 / 12AX7
$39.95

A full, glorious midrange with great texture and liquid detail, extended yet controlled highs, tight bass. Very quiet and low in microphonics. 

Customer reviews 

Users report an open, slightly laidback, tonally balanced presentation, and love how quiet they are. 


Fun fact

Due to the larger plate structure, if you're the kind of person who likes to thwack tubes with their fingernails... these will likely reward you with a loud "PING!" through the speakers. The solution? Don't thwack them with your fingernails! 

RFT ECC83 / 12AX7 (NOS)

RFT ECC83 / 12AX7 Made in Germany
$65.00

These are an often overlooked NOS 12AX7 that was made in Germany. They are low noise, low microphony, and are great in circuits that may be a little tough on other 12AX7s. Somewhat relaxed on top, but they are typically known for having an edgier sound in the mids and bass, not a liquid midrange like a Mullard.

Tungsram 12AX7 / ECC83 (NOS)

Tungsram 12AX7 / ECC83
$140.00

When Kevin thinks of this tube, he thinks of turning up the color, in much the same way classic Mullards do... smooth, maintains top end, excellent bass. The midrange especially is fabulous.


Customer reviews

Customers think of this tube as one that "shines in the entire frequency spectrum", with notable sparkle on top, and a real sense of magic or specialness. There are reports of more weight and definition, greater richness, and lots of increases in soundstage depth. 

Mazda Chrome Plate 12AX7 (NOS)

Mazda Chrome Plate 12AX7
$159.00

More lively on top than the earlier production grey plate. Very neutral and clean, with excellent extension on top. This is not a warm sounding tube, so if that's what you're looking for, check out the Mullards.


Customer reviews

The feedback matches Kevin's description, that this tube is rich and uncolored. Naturalness and references to the real sound of instruments are common, with mentions of good dynamics, and greater precision.

Mullard CV4004 / 12AX7 British (NOS)

Mullard CV4004 / 12AX7 British New Old Stock
$180.00

The most sought-after 12AX7 we have. Glorious mids, smooth as silk, and on the warm side.


Customer reviews

Known to be the "best of the best", and such a huge improvement over old or stock tubes that even skeptics consider these well worth the price. After words such as "glorious", two instances of "gobsmacked", and many, many "wow"s, it's clear that the world will be a little colder when these tubes are gone. To balance out all the fantastic reviews, one customer found them too syrupy in an already warm system, but loved them in a more neutral setup.

Amperex “Medical” 12AX7 / ECC83 (NOS)

Amperex
$229.00

These tubes were used for critical medical applications, so are really special. The internal balance is so tight, the transconductance so healthy, the noise so low.


Customer reviews

The reviews bear out how balanced these tubes are, and "smooth and most enjoyable to listen to". Words such as detailed, clean, focused, and resolving come up a lot, as well as references to musicality.