Should you replace all the preamp tubes?

You are not likely to have to replace them unless one or more tubes fail. Preamp tubes can have a life span of at least two to three years and usually much longer. If it’s been a few years or you regularly change your power tubes and feel like the amp has become lifeless, it may be time to freshen up your preamp tubes.

How often should preamp tubes be replaced?

2 – 3 years
Preamp Tubes are generally at their best 2 – 3 years. Power Tubes are generally at their best 1 – 1.5 years. Rectifier Tubes are generally at their best 3 – 5+ years.

Is it safe to change preamp tubes?

The first thing you need to know about replacing tubes is how to do it safely. It’s no more dangerous than changing a light bulb if you are careful and do it the right way. Make sure you power down the amp, unplug it, and give it adequate time to cool down before you touch anything — tubes can get really hot.

Do preamp tubes need to be matched?

Preamp tubes are, in the majority of cases, self-biasing. Therefore, they do not require matching. Only tubes that are in a push/pull Class AB circuit need to be matched because they share a common bias voltage.

How do you know when to replace preamp tubes?

How do I know when my tubes need replacing? Power tubes like EL34’s and KT88’s are good for about 2500 hours or more. But may go longer in an amplifier with a conservative design. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours.

Can I mix and match preamp tubes?

It is perfectly okay to mix preamp tubes. In fact, it might be recommended in some cases. The reason why some musicians mix and match preamp tubes is because using different tubes can change or improve the tone of your preamp or amp.

How do I know if I need new tubes in my amp?

A: These are the most common signs that tubes need replacement:

  1. Excessive noise (hiss, hum) including squealing or microphonic tubes.
  2. Loss of high end.
  3. A muddy bottom end; Sounds like there is too much bass and note clarity is lost.
  4. Erratic changes in the overall volume.
  5. The amp doesn’t work!

How long does a 12AX7 tube last?

about 10,000 hours
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.

Can you touch amp tubes with bare hands?

It is OK to handle ambient cooled vacuum tubes with bare hands, IF THEY ARE COOL, and skin oils will seldom cause a problem, even if it chars.