10 Best 12AX7 Tubes: Guide and Reviews for 2023

If you own a tube-based guitar, bass, or even a Hi-fi audio amplifier, chances are you will find a 12AX7 being used in them. Maybe even a few of them.

The 12AX7 is the first choice for tube amplifiers. This is because of its high gain and relatively low noise characteristics. But which are the best 12AX7 tubes, and what should you pick?

And even though it’s as popular as it is, most people know very little about them. Even changing one can be a nerve-racking experience. So we are going to change all that with this ultimate guide! We suggest you bookmark this article, so you can return to it when you need to know about the 12AX7!

Best 12AX7 Tubes

Each manufacturer produces a 12AX7 that is its own, and each one has strengths and weaknesses. Some are darker sounding while others are bright. Some are noisy while others are not. So we have created a comparison chart below with some reviews on what we feel these tube brands bring to the table.

We chose these versions because we feel they are some of the best 12AX7/ECC83 tubes on the market. They are still affordable and easy to get. We have provided recommendations for both instrument amplifiers and HIFI applications.

The 3 main things we chose to rate are microphonics, noise, and frequency response.

These are what we feel are some main things you would want out of a 12AX7. So we have given each tube a rating for each of its strengths and weaknesses. The higher the number, the better the tube is in this area.

Our tests were also conducted using many amplifiers. Each capable of different music types:

  • Revv Generator Mk2 – High Gain and clean Tones
  • Vox AC30 – Crunch Tones
  • Marshall JCM 800 – Vintage Crunch and clean sounds
  • Mesa Boogie Prodigy – Bass Amp
  • BoyuuRange Reisong A12- HIFI Amplifier


JJ 12AX7 Tube

Our Ratings

  • Microphonic: 3/5
  • Noise: 2/5
  • Response: 3/5
  • Affordability: 5/5


The JJ ECC83 is a very popular 12AX7 among guitar players and musicians. This tube is well-balanced and is relatively low in noise. JJ has become a very popular and well-known brand over the last few decades. As they make durable tubes with good longevity. They are capable of taking a beating, standing up to aggressive touring and gigging.

This model is warmer sounding than other 12AX7 and is great if you are looking for a darker tone. If you have a harsh or bright sound, this version will tame that harshness. The low microphonics of this tube and gain structure make this a great choice. Especially for guitar amps in the more aggressive realms.

The JJ 12AX7/ECC83 tube is recommended for high-gain amplifiers. Those that are focused on warmer rhythm tones and aggressive sounds. Music like:

  • Metal
  • Hard rock
  • Rock
  • Bass Amps

But they are also capable of delivering superb clean sounds. They can also work for blues, jazz, and classic rock tones. For bass amps, this is also a great choice as they pack a punch.

This JJ ECC83S will work better in instrument amplifiers. It’s not recommended for HIFI applications.


JJ-ECC803s Tube

Our Ratings

  • Microphonic: 2/5
  • Noise: 2/5
  • Response: 4/5
  • Affordability: 3/5


The JJ ECC803/12AX7 is a long plate tube based loosely around the ECC83S. We wanted to include this model in our list because it’s quite different from the 83S. Especially in the high-end response, which had a bit to do with the gold pins. The low-end and mid-range are also different. It’s very full and almost sounds like a blanket was removed from a speaker.

As we played it more, over time it seemed to continue to get sweeter. It’s a great tube and is well-balanced and musical. Any amplifier can benefit from this one, and it will fit many forms of music. Clean tones were exceptional and vibrant. Being as full as it was, we also found the bass amp to respond well to this tube as well.

One thing with long plates is they are known to be a bit noisier, but we didn’t experience that with this model. It was quiet and did not present any microphonic issues.

Unlike the 83S, we found this to be a better candidate for HIFI audio as well and would complement a great system.

This JJ ECC803S will work great in all types of instrument amplifiers. Plus HIFI applications.

Tung-Sol 12AX7

Tungsol 12AX7 Tube

Our Ratings

  • Microphonic: 4/5
  • Noise: 3/5
  • Response: 4/5
  • Affordability: 3/5


The Tung-Sol version is another popular model. This tube is very musical and rich in harmonics. The highs are smooth rather than harsh yet pronounced. Tung-sol is now owned by Electro-Harmonix. They are well-received in the amp world. This is because of the durable and very musical products they make. These tubes are trusted and relied on by many musicians, from hobby to pro.

This model has the ability to tame high-end harshness, but isn’t dark or muddy. Good sounding with great drive. Its bright and sparkly sound is perfect for not only clean tones, but is good for searing leads. The low microphonics and robust build make them an amazing choice for many types of music. They work great in any position in your amp because of their low noise.

The Tung-Sol 12AX7 is a well-rounded tube, and we recommend it for:

  • High gain Rhythm
  • Leads
  • Clean tones
  • Bass Amps

They will fit any form of music very well because of their clarity and well rounded sounds.

While we would recommend the Tung-sol more for instrument amplifiers. They do a decent job in HIFI applications as well.

Genalex 12AX7

Genalex 12AX7 Tube

Our Ratings

  • Microphonic: 5/5
  • Noise: 4/5
  • Response: 4/5
  • Affordability: 2/5


The Genalex Gold Lion 12AX7 is smooth and is an incredible tube. It will increase the performance and definition of your amplifier. This tube has a very broad mid-range that is pleasing to the ear, but isn’t boxy or flat. The detail in the note response is rich, tight, and articulate. Which is everything you could need or want.

The highs and lows are well-balanced, giving this tube a very full dynamic sound. This is considered the best 12AX7 in production and the change is noticeable! And thanks to the great build quality, the noise is super low and there was no microphonic feedback. This model can be used in any position or stage of your amplifier.

The triodes inside this envelope are also balanced to within 15% of each other. This means they also make a great phase inverter or buffer tube. Effect loops will also benefit from this one.

The Genelex Gold Lion is the perfect tube for:

  • Rhythm
  • Leads
  • Clean tones
  • Bass Amps
  • HiFi Amplifiers

We recommend the Genalex Gold Lion for both instrument amplifiers as well as HIFI applications.

Mullard 12AX7

Mullard 12AX7 Tube

Our Ratings

  • Microphonic: 5/5
  • Noise: 4/5
  • Response: 4/5
  • Affordability: 2/5


The Mullard 12AX7 has a long history and has earned a reputation in the NOS hall of fame. Today, the reissue is just as good and a perfect tube for clean or vintage sounds. Because it has a more gritty sound to it when driven into saturation, it serves a better role in the crunch tones. Depending on your amplifier, it may serve well for high gain. But we found it favored classic stuff more.

It has a very warm tone and crisp top end, perfect for low gain feel and leads. When you dig in, the response is everything you could ask for. Good build quality helps keep noise and microphonics very low. This makes it a nice tube for any position in your amp.

Bass amplifiers will make great use of this tube, as it provides a well-balanced sound with a deep low end. And because it’s so well-rounded, it also works like a champ in HI-FI applications as well.

It will serve very well in genres like:

  • Blues
  • Jazz
  • Classic Rock
  • Vintage sounds
  • Bass amps
  • Hifi

We recommend the Mullard 12AX7 for low gain tones, bass amplifiers, and HIFI applications.

Electro-Harmonix 12AX7

Electro Harmonix 12AX7 Tube

Our Ratings

  • Microphonic: 3/5
  • Noise: 4/5
  • Response: 3/5
  • Affordability: 3/5


The Electro-Harmonix 12AX7EH is another great choice. It’s one that doesn’t get the recognition it deserves. This tube is one that you will find comes in a lot of amplifiers right from the factory. This is because of its great build quality and full-bodied sound. Not only that, but you can also find them in a lot of guitar pedals, as they work so well in many applications.

The lack of noise and microphonics was appreciated. Especially when upgrading from lower-quality tubes. The articulation in this model was frequency wide. It kept itself together really well. The bass was rounded but not mushy, and the top-end response was right on point. It was neither sharp nor dull and was pleasing to the ear.

This is a great tube for:

  • Metal
  • Rock
  • Classic
  • Blues
  • Jazz
  • Bass amps
  • HiFi

The Electro Harmonix 12AX7 is great in both instrument amplifiers and HIFI applications.

Sovtek 12AX7

sovtek 12AX7LPS Tube

Our Ratings

  • Microphonic: 4/5
  • Noise: 3/5
  • Response: 4/5
  • Affordability: 3/5

Another awesome tube made to breathe life back into the dullest of amplifiers! The Sovtek 12AX7LPS is a great-sounding tube with low noise and microphonics. Its break-up character is very pleasing. The chewy crunch tones were rich with articulate harmonics.

High gain tones were quite good with well-balanced sound and response. They lean towards the warmer side of the spectrum, but the highs were still present and clear. Being a long plate, I sort of expected more noise from the tube, but was pleasantly surprised at how quiet it was.

For HIFI, this was a great fit, very smooth and full, with no odd noises or funny responses. Bass amplifiers will benefit from this model because of its warmer mid-range punch.

The type of music i would suggest for this tube type:

  • Rock
  • Classic
  • Jazz
  • Country
  • Bass amps

The Sovtek 12AX7LPS is good choice for both instrument amplifiers and HIFI applications.

Svetlana 12AX7

svetlana 12ax7 Tube

Our Ratings

  • Microphonic: 3/5
  • Noise: 3/5
  • Response: 4/5
  • Affordability: 2/5


The Svetlana 12AX7 is a tube designed after a New Old Stock favorite. This model is well received by those who like the old RCA’s because of its smoother frequency output. It has a great bass response, being quite full in the lows but not overbearing. The mid-range is smooth and very present, which was perfect for lower gain crunch tones.

The top end was open without being too bright. This tube is not harsh and doesn’t have the same gain output as some of our more metal-friendly selections. But this makes it perfect for lower gain tones and bass amps. Upon saturation, the structure was not overly gritty or grainy. It was a very articulate and musical experience.

For HI-FI applications, this tube is a real gem as well. It’s well-balanced, refined, and less bright than some other models. This makes it great for this application. It is well worth a try and very affordable.

We suggest this tube type for:

  • Rock
  • Classic rock
  • Country
  • Jazz
  • Blues
  • Bass Amps
  • HiFi Amplifiers

The Svetlana 12AX7 is great choice for instrument amplifiers and HIFI applications.

Groove Tube ECCC83

GT12AX7C Tube

Our Ratings

  • Microphonic: 2/5
  • Noise: 3/5
  • Response: 3/5
  • Affordability: 3/5


The Groove Tube 12AX7 is a Fender-branded model, and it sings. This one has a stronger output, putting more bite into your high-gain tones. Its ability to add beef to a saturated tone is over the top. This is the type that opens up your sound by providing a great presence across all frequencies.

Clean sounds were very rich, and the chime provided a nice experience overall. The crunch tones were full of life and very detailed. Compared to other tubes, this one felt a bit more aggressive. The build quality is great! But because of the added aggression, there was a bit more noise compared to other tubes. A couple of the ones we tried had a slight ring to them when saturated, but nothing crazy.

This tube has that Marshall bite yet has a full-bodied mid-range and solid low end. Perfect for both rhythm and leads. Because of the full spectrum of sounds, bass amps will come to life with this model as well.

This is great 12AX7 for :

  • Metal
  • Hard Rock
  • Grunge
  • Medium gain
  • Clean tones

We recommend the Groove Tube 12AX7C for instrument amplifiers. There are better choices for HIFI.



Our Ratings

  • Microphonic: 5/5
  • Noise: 5/5
  • Response: 5/5
  • Affordability: 1/5


The PSVANE 12AX7-T is an amazing tube for musical instruments and HIFI Applications. This version has a full body, deep bass, and pristine highs. Compared to others, it has a noticeable high-end performance. The Psvane performed better and is richer, thicker, and more complex.

For musical instrument amplifiers, this tube was very well-balanced. The low end is present, but not overly muddy. When saturated, it was thick and fast enough to fill the room in a pleasing way. The top end was not overly aggressive, but rounded and musical.

Running any type of HI-FI equipment that is medium-grade quality or higher? Then you will enjoy these tubes. The experience in both music and movies is well worth the money. They are also very quiet.

We recommend the PSVANE 12AX7-S for all applications.

How to Choose the Right One

Because the 12AX7 is so popular, you are bound to find one or a few in your amplifier. They are used in the guitar, bass, and HIFI amplifiers. You will even find them in pedals that use them for their great tone. But how do you go about finding the right sound for you and your rig?

With all the different types we listed with their strengths and weaknesses, it can be tough to decide.

We suggest you read our reviews carefully and then find the ones that best match your music style. If your amplifier is a high-gain model, then you might even care to mix and match a few in different positions.

Some tubes are better in circuits designed for crunch sounds. So you may want to lean towards some of those models that do it well.

As long as you match the tube to the sounds you are going for, you really cannot go wrong. We chose to review and list these models because they are some of the best you can get today. A lot of them are very affordable, it’s easy to try a bunch out as you discover their great sounds for yourself.

Best 12AX7 Tube For Metal

If you are a metal player, you will need some different high-gain tones that are pretty specific. There are some tubes that are better for metal music than others. If your sound is dark, the wrong tube can completely change your desired tone.

The best current production 12AX7 tubes for metal are:

  • JJ ECC83S: If you like a darker rhythm sound, this tube can be great for that. They are more warm than bright and pretty aggressive.
  • JJ ECC803S: This version that JJ has released is a more balanced sound. It retains the great low end but adds a bit more sparkle to your sound. They are aggressive and can pretty much cover all metal genres.
  • Genalex 12AX7: This is an all-around great preamp tube for metal. Very balanced sound with a mid-range punch and growl. This is a perfect high-gain tone and works in all guitar amps wonderfully!
  • Electro-Harmonix 12AX7: The EH version of this tube is quite balanced, but not as bright. I wouldn’t say it’s as dark as the JJ stuff, but pretty neutral in the top end. This can be a great sound for most metal players.
  • Groove Tube ECCC83: This is a pretty aggressive tube and is very articulate. The reason for this is because of its brightness. It has a good low-end response and will be great for searing lead tones.

So depending on what kind of sound you need, there are plenty of options. To get an even more in-depth description of these tubes, see our comments at the beginning of this article. We go through them all and what they have to offer.

Best 12AX7 Tube

Best 12AX7 Tube for Bass Preamps

Bass and guitar players have different needs when it comes to sounds. Yet the tube options available can serve both. Most tubes can give you a great bass sound, but there are a few that are a bit better for the job.

The JJ ECC83S is a great tube because of its dark nature. For a bass sound, it’s a great option and a very affordable one too. The Sovtek 12AX7 is another tube that should be considered. It’s one of the brands that most manufacturers put into their bass gear because of how well it performs.

The Mullard 12AX7 is also a great, well-rounded bass amp tube that can add some definition to your sound. These options all depend on what kind of bass tone you desire, so some experimentation can help you.

12AX7 In Rock History

When you think of some of the amplifiers that powered the music scene of yesterday. You probably think of brands like Marshall or Fender.

These are iconic amplifiers for sure, but what about the mighty tube that made it all happen? That’s right, the 12AX7 has been used by amplifier manufacturers since the early 1950s!

These little tubes were the driving force of the rock and roll sound from pretty well the beginning. Yet there is little to no mention of it even though it is one of the cornerstones of guitar sounds!

Even today, manufacturers use the 12AX7 because it continues to be the sound in a player’s head. It’s time we give them some well-deserved recognition!

12AX7 Tube Pair

What Is A 12AX7?

The 12AX7 is a 9-pin dual triode, meaning it has 2 sides or amplifiers in one glass envelope or tube. It’s a small signal high-gain amplifier. It can take a small input signal and amplify it a great deal.

This is especially handy in instrument amplifiers. The signal from instruments is very low. Normally in the millivolt range. Each triode or amplifier inside the tube has 3 pins. They control the amplifier and a shared heater element.

This heater element stimulates electrons inside. It’s seen by a faint orange-like glow. The 12AX7 is a part of a large family of twin triode vacuum tubes, each with its own characteristics.

They span a wide range of gain, ruggedness, microphonics, stability, and even lifespan. But the 12AX7 is the most commonly used type of them all, with over 2 million being produced annually.

12AX7 Technical Information

12AX7 Specification And Max Ratings

The label 12AX7 is a series of designates that describe what the tube is capable of and how it is to be used. It’s not simply just a model number. For example, the 12 indicates that the heater will require 12 volts. “A” indicates it’s an amplifying device.

The X indicates its electrical characteristics. While the 7 indicates the number of active pins.

  • Filament Voltage: 6.3-12 V
  • Filament Current: 300-150 mA
  • Plate Voltage (max): 330 V
  • Plate Current (max)‎: ‎6 mA
  • Max Plate Dissipation: 1.1W

12AX7 Pin Out

12AX7 Pin Out
  1. Plate 2
  2. Grid 2
  3. Cathode 2
  4. Filament 2
  5. Filament 1
  6. Plate 1
  7. Grid 1
  8. Cathode 1
  9. Shared Filament

12AX7 Datasheets

For those that are looking for the datasheet on the 12AX7, we have linked to a few pages that may come in handy.

  • Click Here for datasheets to many different tubes including 12AX7.
  • Click here for the JJ ECC83 (12AX7) Datasheet.
  • Click here for the Tungsol 12AX7 datasheet.
12AX7 Vacuum Tube

Different 12AX7 Names And Labels

12AX7 Vs The ECC83

If you have ever opened up your amplifier expecting to find a 12AX7 but found some ECC83s instead, fear not! There is actually no difference between them. Except for the name and place of manufacture. The 12AX7 label is what was used when this type was manufactured in North America.

Today, there are no factories in North America making them anymore. But by request, manufacturers will label them as such. After all, the design is the same. The ECC83 is the label that was applied to this type by European manufacturers, yet it’s the same tube.

So if you ever find an ECC83, you can replace it with a 12AX7 and vice versa. They are the same tube type with just a different nomenclature, so go ahead and use that ECC83 in place of a 12AX7!

7025 Preamp Tube

The 7025 is a name that was given to an upgraded version of the 12AX7 in the 1960s. The upgraded version was quieter and more robust than the standard version of that time.

They were less microphonic and just an all-around better product. A few years later, manufacturers of the 12AX7 began to make their versions in the same manner as the 7025. The new design became standard, and the model was a better production tube.

Today, some manufacturers still claim to make a version of the 7025. But with better metals for a more robust product. They are a bit more expensive, but are quieter than the standard 12AX7. These quieter versions are only beneficial when used as the first stage in a preamp.

The noise floor is very low at the input tube and so the quieter, the better

5751 Preamp Tube

The 5751 version of the 12AX7 was created as a military spec. This tube was given extra support internally and had matched triode sections.

The amount of gain produced by a 5751 is also lower than the 12AX7. Your standard model has a gain factor of 100 whereas the 5751 is 70.

Some people refer to the 5751 as being a 12AT7 because it too has a gain factor of 70. But this simply is not the case, as the plate resistance of a 5751 is the same as a 12AX7. You can use a 5751 in its place, but keep in mind it will produce lower gain.

So if you want to tame an amplifier with too much gain, this is the tube you want to use in select spots of a preamp.

You can also use this tube in the position of the phase inverter to produce less power from an amplifier.

12AX7 “A” and “B”

The 12AX7-A and B are two tubes that are identical in nearly every way. You may have come across these two labels in your hunt and were curious about the differences. They are made in the same batches and are pretty much the same tube, but some of them come out producing high gain.

The 12AX7-A is a higher-gain version of its counterpart. For all intent and purpose, the “B” version is simply a screened tube selected for its high gain and low noise. The ones that had higher gain and were noisier may have simply been named 12AX7-A.

Mesa Boogie and Peavey use 12AX7-A labeled versions. This is because of the higher gain, but this comes at a price of a noisier output sometimes. But if you want a gain monster for an amplifier and are not worried about noise, the 12AX7-A is your animal.

If you want high gain and a quieter, even softer tube sound, the “B” version is your best bet.

Microphonics And Noise

Checking a 12AX7 For Microphonics

One of the common terms used among tube amp owners is microphonic. This is a go-to term used when issues with an amp arise. But what does it really mean? When manufactured, they are tested for a number of different things to verify they are good tubes.

Noises are one of those tests. To find out if the tube is microphonic. A microphonic tube is susceptible to external noise and amplifies it. In most cases, it will ring like a bell if tapped on.

Now, most will make noise when they are used in the input position. So it’s important to note that it will make a sound when tapped on because of the noise floor. It’s that a rugged tube with low microphonics will normally make a thud-type sound. But the flip side of that is it will ring and produce a very high-frequency noise.

A word of caution, when you tap on a tube to check it, don’t tap too hard. It is an electronic, mechanical device that can be damaged if it’s hit too hard.

Are Microphonic Tubes A Problem?

It’s a fact that tubes produced today are not what they used to be. In some cases, there are little to no tests done by some manufacturers. Most tests are done by amplifier builders to weed out any poor ones.

Sometimes batches of microphonic tubes will make their way to an amplifier manufacturer. But this does not mean that they are all unacceptable. In fact, some microphonic tubes have the potential to outlast those that are not. And all are to some degree, so it’s impossible to have a perfect version.

The trick with these microphonic tubes is making sure to not use them in certain positions. Especially those with a low-noise floor. For example, you do not want to use one that is noisy at the input position of a pre-amp or a tube-driven effects loop.

The noise floor at these positions is very low, and the ring sound of a tube will be very noticeable here. It’s always better to use a microphonic tube in a position where the signal levels are larger.

Some are more so than others, however, so it’s important to keep that in mind. If the tube is so poor that it is unstable, it’s best not to use it at all. If it’s got a slight ring to it but is somewhat stable, it will probably be okay.

Tube Dampers For Microphonics

There are products on the market that can help with This. Tube dampers can be slipped over the outside. In order to prevent the ring of a microphonic individual.

Dampers can also help with mechanical noises that might be heard from noisier units. Aramox makes a great damper. They can be reused with any tube you install to prevent any noise and are extremely affordable.

Have noises you want to get rid of? Try their dampers and see if it solves your issues.

Understanding 12AX7 Tube Noise

So now that we have touched on microphonics, it’s important to talk about tube noise. A noisy unit will make noises, hum, and even pop occasionally. This is not desired! Especially in an amplifier designed for high-gain guitar or a Hi-fi stereo system! 

But all types have a noise floor, this is not avoidable. Typically, a tube will produce a soft hiss or white noise, as it’s often referred to. This is normal and will be different between tubes, as some produce more than others.

You are more likely to notice white noise in a guitar amplifier built for high gain. Amplifiers like this have many triode stages connected in series. Each stage will amplify the white noise of the input stage, making it more noticeable.

And so using the quietest tube you can find in the input or first stage will always be your best bet. Some amplifier companies like Mesa Boogie take the time to find the quietest tubes.

They then sell them for the first stage or input stage of high-gain amplifiers. So if you play with high levels of gain, you are more likely to have a better experience with these quieter tubes. They will produce less white noise and are perfect for the first stage in all amplifiers!

Tube Crackles And Pops

So what kind of noise does a tube have to make before it should be replaced? If your 12AX7 begins to make any pops or crackles, it’s probably time to replace it. If they are brand new, and you put them in, they may crackle.

Don’t worry, in most cases, this is just the tube burning in and cleaning impurities off of its internal parts. We recommend that you leave the amp on for a few hours to let them settle in. If after a few days it continues to make these sounds, it’s more than likely an inferior tube.

But if you have had yours in an amp for years, and it starts making noises, it’s time for a replacement.

12AX7 Lit Up

Vacuum Tube Pin Straightener

From time to time preamp tube pins can get bent. This can do damage if it’s not straightened properly. If you have paid a lot of money for tubes, the last thing you want to have happened is a crack due to bent pins!

Bent pins or even slightly bent pins will also make it harder to insert tubes into their sockets. This as well can do damage and wear sockets.

Riverstone Audio makes a great stainless steel straightening tool for 12AX7s. Every tube owner should own one. They are super affordable and are a much better alternative to needle nose pliers.


Which 12AX7 Sounds Best?

This depends on the sound you are going for. Looking to open up your sound? Want to give it blossom and a very dynamic sound? Then the Genalex Gold Lions will get you there. They are an incredible tube and will work in most circumstances. If you are looking for a darker sound, the JJECC83 is pretty dark to the point of being almost muddy in some amps.

If that isn’t quite right for you, then the Tung-Sol would be next in line. It isn’t quite as dark, but is a pretty balanced tube with great projection. Less congested than the JJ. For those looking for a tube with a great high-gain bite that is less expensive. Then you may want to consider one of the Shuguang versions.

Overall, the Tung-Sol would probably be the best bet for bang for your buck in most cases. But if the price is not an issue, you will want to try the Gold Lions.

How Long Do 12AX7 Tubes Last?

A 12AX7 is generally designed to provide 10,000 hours of service. At least before you should consider changing it. Yet, tubes are like light bulbs and can just stop working one day out of the blue. Even under the 10,000-hour mark.

A 12AX7 is an electromechanical device that also contains a heater element. Shock to the tube could displace the elements inside, causing issues. Even the heater element could just burn out. Nothing is guaranteed! One tube may give you the full 10,000 hours, while another only gives you 4.

This is the way it goes with tubes. Yet, most manufacturers provide great warranties to make sure you get good products. So always buy from a good vendor. This is why we recommend Amazon.

My 12AX7 Flashes At Start-Up

A flash from a 12AX7 is normal at start-up and is nothing to worry about. Over the course of time, this may even go away. New tubes will often do this for the first few start-ups. There may be some gasses that remain from manufacturing. But we have found that it stops flashing after a few uses.

If you see your power tubes flash at start-up, this is not normal! If this happens, turn your amp off and get it serviced. Flashing is bad and could cause damage to the amp.

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Don East

My name is Don East, I'm the editor for Killer Rig. I've been playing guitar for over 20 years and have designed and manufactured products like guitar amps, effects pedals, and more. Over the years I have played in many bands and have a deep love for quality gear. I am an electrical engineer and have a passion for music gear, and now want to share what I know with the community!

1 thought on “10 Best 12AX7 Tubes: Guide and Reviews for 2023”

  1. Very clear and comprehensive explanation of 12AX7 tubes. Really appreciate such a resource. The guitar world needs you. BTW put Gold Lions in a Marshall TSL60 and it became a beautiful blues amp. Worth the $.

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