Tube Cool Down Q

kevhed72
kevhed72 Posts: 4,950
What's a safe time to swap out pre amp tubes....I'm stalling on my real work and decided to pop in another set

Comments

  • pitdogg2
    pitdogg2 Posts: 24,477
    when they are cool :p Honestly I have a pair of rubber coated Kevlar gloves for steel work I found work great. First I bought them for a steel roof I was putting on and then found they work great for not touching tubes and leaving skin oils on the tubes. IT just happens that they are great insulators for hot tubes.
  • heiney9
    heiney9 Posts: 25,053
    I use rubber gloves and for signal tubes I usually wait like 5-7 minutes before swapping. But really, you could do it right after power down. Rectifiers and power tubes are a different story.

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
  • mhardy6647
    mhardy6647 Posts: 32,926
    Other than a rectifier tube, most preamp tubes should run pretty cool and require minimal cool-down. This being said, you might find some components that run even small signal tubes hard enough to get 'em hot... but most of the time, in well-designed preamps, the small-signal tubes shouldn't be what I would consider hot even when up and running at steady state.

    Power tubes and HV rectifiers are worth waitin' a few minutes before touching, though ;)

  • lightman1
    lightman1 Posts: 10,776
    I had St. Elmos fire going in an eight set of 6550 power tubes.....No touchy for a long time!