Pass Labs x250.8 vs tube amps

Hello all

Have been building amps for 40 years and built/auditioned a lot of circuit topologies both ss and tube.

Re warmup time- it should not be more than 15-30 mins for tubes depending on the ambient temp and 1 hour for pure (very rare) class A for ss.

Re sound quality, nothing beats thermionic emission in sound reproduction, nothing (in my experience). You could go pure class A SS with the best topology million dollar components in the signal path and still fall short of a lousy mediocre Chinese built tube amp running pentodes in ultralinear class AB. Go with more bias, SET and triodes and you are in heaven. Want more bass reproduction fix your psu. Matching tube impedances with transformers, and different tubes is a way to fix any topological issues.

Wont even touch tube OTL designs as those are unique and sound 10 times better than any tube transformer amp but more moody than an angry woman

.. and to avoid misunderstanding I would advise as follows:

a) if you are a purist and would not accept a "fly on your sword" then it is obvious where to look

b) if you want a plug and play solution which would give you the very good results in a low maintenance environment for with SS class A

c) if you want a excellent solution on a plug and "pray" scenario which will require biasing, tube rolling, and more hands on work go with tubes

Subjectivity does not win over physics..

The most important thing is you love the sound after the warm up.  That is hard to achieve and I wouldn't want to risk losing it by switching components.

The problem seems to be the long warm up and the heat.  A "cheap" solution would be to leave the amp on all the time and buy an air conditioner for a couple hundred dollars.  Presumably, your listening room has a window for the heat exhaust.

You could leave the amp on all the time with the door closed and turn on the air conditioner half an hour before you want to listen.  And of course turn it off while you listen because it's noisy.

It’s not the amp, it’s your ears and what’s between them.  Listening to music that you enjoy will release hormones like dopamine. Listening to songs you like, and more importantly, allowing yourself to relax and enjoy the music will speed up the process. The amps casing and heat sink temps that you seem to be measuring  have nothing to do it. But you guys go ahead and disagree, I enjoy reading many of the different explanations and recommendations. 😄

Nope, the placebo effect has nothing to do with this on a blind AB test. Topologies do matter (a lot), and distortion as well as harmonics which are more enhanced in some designs are both received and acknowledged by the human brain.

The heat that is mentioned before by jwei does impact the sound in a class A environment but within a few minutes of powering up again depending on the design of the amp. Heat affects also, inter alia, the impedance of components sometimes materially.

The only mistake people make in this is treating it as an overly simplified subjective affair. It is extremely complicated that sound engineers may spend a lifetime to master. Even the room construction topology merits attention with sound interference patterns being closely monitored and with millions of budgets invested in serious philarmonic venues.