What are octal power tubes?

An octal tube is a vacuum tube that has an 8-pin base with an 11/16″ diameter keyed locating prong called a spigot in the center. This tube base was introduced by RCA in 1935 for their new line of metal tubes, which they called an “Octal base”.

Do power tubes affect tone?

It has no effect on the sound. This phenomenon only happens in a tube with better-than-average vacuum (pure). Therefore, the tube is actually a better-quality tube!

How do you match power tubes?

If you can’t find a tube tester, you can still match power tubes. Simply use a preamp or power amplifier to measure the plate current draw of both the tubes! If the plate current draw of both the power tubes is the same, then congrats! Your power tubes are matched!

What does a power tube do?

A power tube is essentially a control valve used to regulate the flow of electrons. (This is why guitarists across the Atlantic refer to our little glass friends as “valves” rather than “tubes.”) The electrons flow from a part of the tube called the cathode to the tube’s plate, as shown in Figure 1.

Do different tubes really make a difference?

The difference can be very large, especially if the existing tubes are old. The old tubes might “test good,” but they can sound lame compared to better ones.

Do power tubes have to be biased?

Thus, no biasing is required when replacing tubes — but using a matched set of replacement output tubes is, once again, highly recommended for obvious tonal reasons. Amps with cathode-biased power-tube circuits are lower-output ones — 30 watts or less.

How long do vacuum tubes last?

Tubes don’t just “quit” suddenly. They lose their drive capability gradually with use. 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.

Does changing power tubes make a difference?

Do all 4 power tubes need to be matched?

Power tubes require matching because the way they amplify signal can create exceptionally bad sound if they are poorly matched, but pre-amp tubes generally aren’t used this way and so matching them is unnecessary.

How do you know if your tubes are matched?

one has to test both tubes at the operating voltage of the amp being used. it doesn’t help if your tubes match perfectly at 200v of your tube tester but your amp operates at 275v… using a multimeter with a bias tool probe is your best bet.

Are tube preamps better?

A tube preamp tends to have warmth and smoothness that a solid-state often lacks. Because of the way they work, driving the tubes creates a subtle but smooth distortion adding a pleasing character to the tone. This doesn’t necessarily constitute distortion in the sense of ‘overdrive’ but rather more color or character.

Are tube amps really better?

Are Tube Amps Better Than Solid State? Tube overdrive is much smoother and more responsive than solid-state. It can be influenced by adding high-gain pedals to the signal chain between the guitar and amplifier, and this gives players much more control over the sound.

What is an octal tube?

What is the best octal preamp tube?

The 6SN7 twin triode (amplification factor 20) is the octal preamp tube most people seem to be using despite it’s low gain. It is said to be quieter than the other octal twin triodes and is used in many tube hi-fi amps.

What is a 9 pin miniature tube?

This is a 9 pin miniature tube not an octal, but it is interesting. It has a pentode and a triode in a single bottle like the ECL82 and ECL86. But the pentode section is not a power amp like those other tubes. It is a preamp pentode.

What is the most common tube base?

Until the introduction of miniature (Noval base) tubes, such as 12AX7 and EL84, the octal base was the most common and popular tube base. Some common octal tubes are 6V6GT, 6L6GC, EL34, 6550, KT88, 6SL7, and 5AR4.