I own 2 LTA amps now and I’ve also owned the LTA Ultralinear. These amps do run the tubes significantly cooler and stress them less than other amps using the same tubes. I’ve also talked to Mark several times at audio shows and he really seems to know his stuff.
I can see why he would recommend leaving them on because every time a tube amp turns on and off, that’s wear and tear on the tube. Even if it has soft start circuitry. An example, I have an older Modwright pre amp and the on/off toggle switch was damaged in shipping. I didn’t know that and when I started using it, the on/off switch made intermittent contact and rapidly shut the pre on and off a bunch of times. That quick series of powering up and down was enough to kill the rectifier tube and also F’ed up the driver tubes. Quickly turning tube amps on and off is really hard on the tubes.
That said, I wouldn’t leave the LTA amps on all the time either. If I’m just going out for an hour or so and I plan on listening when I come back, I’ll leave it on. But I wouldn’t leave them on for long periods if I’m not around. Too paranoid for that. They have built in protection circuits but my thought is, why risk it? I’d rather not have a fire happen that I could’ve prevented. Imagine trying to explain to the authorities what happened. “Yeah, I leave my tube amps running all the time... Oh, you don’t know what tubes are? They’re gas filled bottles that run hot and at high voltages.”
