Q: How long should I let my tube gear warm up before using it?
A: The gear will “work” not long after you power it up. However, in our experience, it takes 15-30 minutes before tube gear is sufficiently warmed, and we have found that the tone of the signal can change substantially during that time period.
Some manufacturers recommend as long as an hour of warm up. And, some techs recommend that before bias is adjusted, a tube amp should be warmed up for at least an hour.