JJ Electronics Amplifier Tubes VS Fender Groove Amplifier Tubes – Which 12AX7 Preamp Tubes Are Better?

Also known as ECC83, the 12AX7 preamp tube was originally engineered and manufactured by RCA electronics company. Nowadays, a variety of companies produce 12AX7 preamp tubes including JJ Electronics in Slovakia and Shuguang in China, commonly referred to as Groove tubes.

If you own a tube amplifier or considering using one, then you probably already know how crucial a 12AX7 preamp tube can be in your setup. Depending on the amp’s design and the number of gain stages it includes, you can get a wide range of tones from sparkling clean and mellow bluesy all the way to raging metal and everything in between.

In this article, we’ll be comparing two of the most popular 12AX7 preamp tubes: the JJ Electronics amplifier tubes<span style=”font-weight: 400;”> and the Fender Groove amplifier tubes.

What are 12AX7 Preamp Tubes?

Tube amplifiers use vacuum tubes that basically look like light bulbs with a pointed protrusion on the top. Vacuum tubes are made of glass that’s sealed with no air inside. These tubes are present in a couple of different types inside the tube amplifier, such as preamp tubes and power tubes.

Each tube type serves a specific purpose, all of which work together to create the guitar’s final tone. Preamp tubes contour and condition the general properties of the incoming signal (distortion or overdrive), while power tubes control the output of the amplifier.

Almost every tube amplifier out there (Fender, Marshall, Vox, Mesa Boogie, Peavey, and many others) includes at least one and up to five 12AX7 preamp tubes

The first gain stage of a preamp tube is when you hit it with a substantial current (for example, from an active pickup or a pedal) to produce richer harmonics, sustain, and distortion. Some tube amplifiers feature two, three, and up to four gain stages. This is referred to as cascading gain stages.

Breakdown of the JJ and Groove Tubes

On your search for 12AX7 preamp tubes, chances are you’ll come across the JJ amp tubes and the Groove amp tubes. Many will tell you they’re the exact same, others will say that there are differences, so what’s the deal? We’ll let’s take a closer look!


Both 12AX7 preamp tubes are made the same way. Each one is a 9-pin miniature, high-mu, twin triode. Here’s what this means:

The 9-pin miniature part refers to the type of socket where you’ll be plugging the tube. It consists of nine fine pins arranged in the shape of a circle with a diameter of approximately half an inch. To make sure that the tube can be plugged in one way only, there’s a wide gap between pin number 1 and pin number 9.

The high-mu part corresponds to the amplification factor, which is abbreviated by the Greek letter μ (mu – it’s pronounced as ‘myoo’). It refers to the general amplification category of this preamp tube as opposed to other kinds of preamp tubes such as the 12AU7 “medium-mu”.

As for being twin triode, this means that each preamp tube carries two identical triodes inside its structure. A triode consists of three electrodes (plate, grid, and cathode), and it’s the most basic tube configuration for signal amplification.

As you can tell, both the JJ and the Groove 12AX7 tubes are built essentially in the same way.


The JJ 12AX7 preamp tubes do feature a unique plate design from what you can see in most 12AX7 tubes on the market. The compact build of the plates doesn’t dampen the tubes’ sound or dynamic response. They actually seem pretty rugged and suitable for musicians on the road.

The JJ 12AX7/ECC83s preamp tubes deliver a rather well-balanced audio profile. They have a better mid and high range compared to the original JJ ECC83, so it’s quite obvious that the company did its homework. These tubes are also smoother and more natural, especially when you play them clean.

The chime and sparkle are great, the tubes maintain all of their definition at every level of saturation. Even when overdriven, the JJ ECC83 remains lush and thick without compressing as hard as the previous version.

As for Groove Tubes, they offer a very strong output. Some may consider them super close to being microphonic, but make no mistake – they aren’t. They deliver a lot of clarity and punch when it comes to the clean channel.

Groove Tubes have less midrange than JJ’s, yet they’re still bright with a good bottom end crunch. They can be wonderful for heavy distortion such as the case in metal solos, and they work pretty well with low wattage amps.

This specific 12AX7 C version is an improvement of the 12AX7 A and 12AX7 C since it has higher gain and lower noise. So if you already own the A or B variant but you’re having microphonics and noise issues, you can go for the C version to get rid of the background noise without losing the gritty attitude.


The price point can be the deciding factor for you since both tubes will do their basic job rather efficiently. Fender Groove Tubes can end up costing you about twice as much as you’d pay for a JJ’s tube. 

Now, JJ amp tubes aren’t exactly expensive in the first place, but as we all know; tubes don’t last very long. This means that you may want to think about the long-term cost if you’re one to go through tubes quickly.

Wrap Up

The bottom line? Well, as far as construction and overall quality go, we’ll have to settle for a tie. Both the JJ and Groove 12AX7 tubes can give you what you want, depending on what you’re trying to achieve.

JJ tubes sound warmer, they’re natural, smooth, and thick. They clean up too much, so not the best for low-watt amps. Groove Tubes, on the other hand, can be a better match. Also, they do a good job for heavy distortion with higher gain and less noise than ever.

Comparing the two tubes side by side, JJ’s may sound different enough to favor in a rehearsal or a recording. But for playing live, it’s not worth the switch.