2. amps-preamps
  3. 161353-98013

Pass Labs x250.8 vs tube amps

I have a beautiful system. Lumin X1 > BAT Rex 2 pre > Pass Labs x250.8> Sound Labs M545 (ESL) in a tiny room (9x 11 ft).  This system has the most glorious SQ: smooth, detailed and powerful , along with great bass. I would say this sound equals or betters any ultra high end system. HOWEVER, I have a problem. My system takes 6 hours of music playing to sound this good. I had X250.5 and I had the same issue. Leaving it on idle overnight doesn’t solve the problem. It is 15 W class A, so it generates quite a bit of heat, and yet I have to still play music. Because my room is small, I don’t crank up too much- maybe this is the problem, but the temperature doesn’t complete stabilize for 5-6 hours. The top reaches 107 deg in 2 hours, but the front plate doesn’t reach 107 until the 6 th hr when it starts to sound glorious. I have never had a tube amp and I am wondering if I can reach that thermal equilibrium and the glorious SQ faster with a tube amp? I worried about the heat generation with a tube amp in this small room, but X250.8 generates 450 W just idling. This is no worse than tube amps like Audio Research 150 Se, which I demo’d and was impressed by. BTW, I need power in the amp because of the esl speakers.
What do you all think?

128x128chungjh
jwei
139 posts
 

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.

perkadin's avatar
perkadin
286 posts
 

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. 😄

sofos
3 posts
 

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.

 

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