Four Hour Tube Amp Warm-Up

@bigtwin I cannot think of a single Tube Amplifier manufacturer that would say leave it powered on. Nor a Hybrid tube SS manufacturer.  

It’s difficult to really know for sure because I’ve not listened to the same music at 30 minutes, 1 hour, 2 hours etc. It’s also difficult to remember & accurately compare w/ that time lapse in between. I don’t think our sonic memory is that good over time, even relatively short amounts. 
 

“Warm up” time could also be be within in our brains & it takes me time to relax, unwind & really get into the music & really enjoy it.

That all said, I have noticed w my Rogers EFH 200 Mark II ( 2- KT 150’s per side & a seriously large power transformer) that the sound definitely sounds more full body & fleshed out after about 1 hour. Beyond that , I can’t say much. 

My 300B SET amplifier also sounds it best after 3-4 warm-up hours. After 1.5-2 hours it sounds not bad but not as magical smooth and clear as after 3-4 hours. 

When I had transistor amplifier Plinius 8200 integrated it was always on. Without couple of days warm-up the sound was hard to listen to.

I am really sorry to hear your system requires such an extended warmup. For tube equipment this is simply rediculous. I have owned a PrimaLuna integrated amp for over 10 years in my home office. I may have never discovered it’s sweet spot. I seldom have spent more that two or three hours in my office.

My main system is contemporary Audio Research Reference gear and my headphone system is Woo 300b… and neither have much of a warm up gain. In the past the Reference 5 series premps had a strange ~ 12 minute requirement to have signal passing through it until reaching optimal sound quality… it could be on for hours… but still had to have a signal going through it. This went away with the 6 series preamps. I don’t hear a noticeable improvement after the first couple minutes.

In decades prior, my equipment had a noticable improvement after 15 minutes or twenty… nothing like four hours.

All tube amplifiers sound OK after 30 minutes. But if you listen carefully sound is getting better during 2-3 hours. Especially it is true for not feedback circuits. I also paid attention that this difference gets bigger after I tweaked and improved sound quality my 300B amplifier. I had McIntosh MC30 and Marantz 8b amplifiers. All of them benefited from couple of hour warm up.
Another fact, in recording studios all used tube equipment is switched on in start of the day and switched off in the end of the working day.