Tube Amp Burn-in

I think that perhaps it would be close. Certainly more than 20 HRS, but, since you're talking tubes, which have to be replaced, I'd just let it break in over time, and not leave it playing 24/7.

I've heard that Transformers and power supply parts sound best after many years of use. Don't sweat it. Your amp will sound loads better than a SS amp right out of the box!

have fun...
Joe

Normally tubes take about 100 hours to burn in. I recently bought a used 100/100 and am waiting for it to arrive. What is your associated gear and what have you found so far. At 100 hours the tubes start to really warm up and even better at 150 hours so be patient. Also if you can identify what you like and do not like tube amps are easily changed by other tubes. I have heard a lot of good things about the Svetlana kt 88. I will probably get a set myself.

My associated gear for the PA100/100 is a VAC Standard Pre LE w/MM phono. Got a Well Tempered Classic turntable and a Creek CD43 CDP. I wasn't sure what I thought early on, but it does seem to be improving. Better focus. I've probably got 40 to 50 hours on them so far. My speakers are Alon Model 1's and I'm currently speaker shopping. Been thinking about the Merlin VSM-M w/full BAM setup.

I've also heard Svetlana KT88 tubes were nice with the PA100. I'm probably going to try some NOS tubes in my pre first and then work on new ones for the PA100.