Another way to check would be to place them into a known 12AX7 circuit and without touching anything, note if there is any appreciable difference in gain or volume between the two. The 12AU7 in most if not all cases should be a bit lower, being it has a lower amplification factor than the 12AX7.

How do you know if a tube is 12AX7?

Look at the print on the vacuum tube to identify it. A series of numbers and letters is printed on the side of every tube. This code is what you use to figure out where to place the tube in the tester. For example, the lettering on the tube reads something like “12AX7.”

What tubes are compatible with 12AX7?

You can interchange a 12AX7 with 12AT7, 12AU7, 12AY7 or 5751 as they are all the same pin structure, however they will each give you a different result in your amp. Each of these tubes has a different gain factor, which means some will give higher gain and others lower gain.

Are all 12AX7 tubes the same?

All 12AX7 tubes have an amplification factor (μ) of 100 (high-mu). Ideally, every 12AX7 should yield the same gain when placed in the same circuit. However, in reality there are comparative gain differences among 12AX7s.

What is the best sounding 12AX7 tube?

Best 12AX7 Tubes for Hi-Fi Reviewed1 Genalex Gold Lion Best 12AX7 Tube for Hi-Fi. See more reviews. 2 JJ 12AX7 Preamp Vacuum Tubes (ECC83) for Hi-Fi. See more reviews. 3 Tung-Sol 12AX7 Preamp Tube for Hi-Fi. See more reviews.2 Sep 2020

How long does a 12AX7 tube last?

Small signal tubes like a 12AX7 or 6922 will work well on average for about 10,000 hours. If you leave your equipment on 24 hours a day, well you do the math: There are 8,760 hours in a year.

What does a bad preamp tube sound like?

Preamp tubes usually cause problems through noise or microphonics. If noise, you will hear hiss, crackling, popping or similar issues. If you hear squeal, hum or feedback, it is typically a microphonic tube. You can try tapping the tubes like you did the power tubes and see if the problem worsens.

Are all preamp tubes interchangeable?

You should be able to swap preamp tubes of the same type without problem. For example, any 12AX7 should be compatible with another 12AX7. In some cases, “families” of tubes, mostly preamp tubes, are compatible, such as the “12A” family of preamp tubes — 12AX7, 12AT7, 12AU7, 12AY7.

Can I use 12AX7 instead of 12AX7A?

Correct. The 5751 has a lower mu than the 12AX7A so these are NOT equivalent. NEVER replace a 12AX7(A) and its equivalents numbers in a phono preamp unless youre sure RIAA correction does not depend on its characteritic values. Often low noise was obtained by

Can I replace ECC83 with 12AX7?

What is the difference between a 12AX7 Valve and an ECC83 valve? The answer is simple – there is not the slightest difference between these two valves. They are identical. They only differ in name.

How long do 12AX7 tubes last?

Small signal tubes like a 12AX7 or 6922 will work well on average for about 10,000 hours. If you leave your equipment on 24 hours a day, well you do the math: There are 8,760 hours in a year.

Whats the difference between 12AX7 and 12AX7A?

12AX7A is an updated lower noise version of 12AX7, and as Mr. Hoffman said it has to do with the way the heater is designed. Another 12AX7 update are 7025 tubes which are supposedly less noisy than 12AX7A and with lower hum, again because of heater being redesigned.

How do I know when my tubes need replacing?

A: These are the most common signs that tubes need replacement: Excessive noise (hiss, hum) including squealing or microphonic tubes. Loss of high end. A muddy bottom end; Sounds like there is too much bass and note clarity is lost. Erratic changes in the overall volume. The amp doesnt work!Jan 31, 2005

How do I know if my preamp tube is blown?

If you hear unwanted distortion or crackling noises coming from your amp, you most likely have a blown preamp tube. Put your amp on the cleanest setting (in other words, turn off all distortion). If you can still hear distortion or crackling noises, you probably have a blown preamp tube.

Can I mix preamp tubes?

Having given that disclaimer and warning, here are a few guidelines: You should be able to swap preamp tubes of the same type without problem. For example, any 12AX7 should be compatible with another 12AX7. With power tubes, you can swap different brands of the same tube.

Can you use a 12at7 in place of an 12AX7?

While you can physically use a 12AU7 tube in place of a 12AX7 in a circuit, its not recommended to do. Most circuits that are designed for a 12AX7 will not react well to the significantly lower gain of the 12AU7.

Are 12AX7 and ECC83 interchangeable?

What is the difference between a 12AX7 Valve and an ECC83 valve? The answer is simple – there is not the slightest difference between these two valves. They are identical. They only differ in name.

Can a 12AU7 replace a 12AX7?

Technically, yes, you can physically interchange a 12AX7 tube for a 12AU7 tube in your amp without risk of major damage to your amp.

Can I replace 12AX7 with 12AT7?

You can usually swap out 12AX7 tubes with 12AT7 tubes if you want a cleaner guitar tone with more headroom, and dont mind a drop in volume. You may need to look into your guitar wiring to get the proper resistance load necessary to use a 12AU7 in place of a 12AX7.

Can I substitute 12AX7 for 12AX7A?

You can substitute a 12AX7A, a 7025, or if you only need a single triode a 6AV6. A 6EU7 is the electrical equivalent with a non-paralleled heater. Different pin-out too.