I tried to speed up the warm up process by putting a towel over the amp. This is what Kent English at Pass does before shows. It does get the temperature up much quicker. However, it still took another 2 hr of music playing to sound GREAT. Kent thinks it is the diff pair in the input stage which runs at a constant current and it can't be fooled.
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?
What do you all think?
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- 74 posts total
Similar topics surface periodically about the 250.8 over on AC. This thread is from a few years back, 1,2,3 pages worth...warmup, standby / master switch, SS vs. tubes. https://www.audiocircle.com/index.php?topic=149400.0 |
I own a BAT VK-33SE preamp and VK-255SE power amp. My speakers are 88 Db efficiency. The amp drives them effortlessly, with plenty of safe headroom, and I find it to sound it's best after about 30 to 45 minutes. It gets quite warm by 30 minutes, maybe you could say hot, but never a room heater. BAT products work very well with one another. They are designed and engineered to do so. The VK-255SE amp is one of the most "tube-like" sounding solid state amps available. Since you have a BAT Rex-2 preamp it would be a very good decision to match it with a BAT power amp. That's one suggestion. Another suggestion is to get a BAT tube amp. The Rex-2 power amp (as well as the Rex-2 preamp) have both been recently replaced with the next-generation Rex-3 products. Thus, the Rex-2 power amp can likely be had at a nice discount. You may wish to contact Upscale Audio about that. They have a Rex-2 power amp set up as a demo unit. It is only switched on when a demonstration is requested. I visit the store fairly often and can tell you that amp is in absolute perfect condition. Upscale Audio is a wonderful retailer to do business with. I am confident they would work a nice price for you on that unit. Anyway, I thought you may want to take into consideration pairing your preamp with the engineered mate of power amp and also provide you with a very good path for such opportunity. Best of luck to you. |
- 74 posts total