Speaker coils? Hmmm...my Freya sounds great as soon as the tubes warm up and my Pass XA-25 takes maybe an hour or so but sounds so good immediately you sort of forget that. I wouldn’t think about that if Nelson hadn't mentioned it in the manual. I sometimes swap out the Pass for a Dennis Had Firebottle SEP tube amp that seems to sound great immediately, and If the speakers coils are cold you need a warmer room. Preheat ’em with a heat gun...knit them a cozy...a hug...some tea...insults...
Tube Preamps Should Have This Feature
So it's late or you just want some casual listening for a short time. "Should I fire up my tube pre for 30 minutes?". My answer is "No". Why not let me flip a switch (or push in the volume control) to put my pre into "bypass" mode? Bypass would, effectively, convert your pre into a passive device, keeping the tubes dark.
This sounds useful to me.