|Pass Laboratories X150.5 Stereo Power Amplifier|
|Home Theater Power Amplifiers Stereo Amplifiers|
|Written by Christopher Zell, Ph.D.|
|Saturday, 01 November 2003|
Page 3 of 3
As previously discussed, while I have no major complaints with the impressive sonic performance of the Pass Laboratories X150.5, I do have an issue with the loudspeaker binding posts on the review sample. They seemed out of place in quality when compared with the rest of the X150.5. An amplifier in this price range ought to have much better posts that are more versatile and robust. Not only would they not accept any kind of banana plug, they would not easily handle any large-diameter loudspeaker cables. One other minor item is that that the amplifier does run quite hot, which the buyer should be aware of when thinking about amplifier placement, as well as room issues such as ventilation and cooling. This is more of a warning than a criticism, one inherent in any amplifier with high idling bias currents in the output stage.
Despite the fact that there are plenty of more expensive amplifiers out there, most folks, myself included, would consider $4,500 a healthy chunk of change for a stereo power amplifier. A product at this price point had better deliver on all fronts, and with the exception of the binding posts, the X150.5 certainly does to both my ears and eyes. The Pass Laboratories X150.5’s stunning and tasteful cosmetics, combined with powerful, dynamic yet non-fatiguing sonics, make it a real winner. I am always wary of characterizing the sonic attributes of an amplifier using terms such as “soft,” “etched,” etc. since the effect depends so much on surrounding components and source material. Comparisons without matched level testing in the same room and with the same system are also extremely dangerous, as normally the conclusions are wrong or at best exaggerated. Still, I’ll do my best here to characterize my impressions of the X150.5. I doubt anyone would ever call this amp forgiving, euphonic and lush, or the bottom end rich and fat. The X150.5 consistently sounded very live and dynamic, partially because of what I perceived as a very low noise floor. The highs were very clean and extended and sounds such as high hats in particular were very impressive through the Pass Laboratories amp. The lowest octaves seemed a tad lean at times, which is again neither good nor bad, and the bass was liquid and tight, not bloated, while still powerful when called for. The X150.5 was very revealing and detailed, so that bad recordings were thrown right back at me, but without any extra sizzle to render them unlistenable, just revealing the ugliness that was already there. I noticed that vocals seemed a bit further back or very slightly recessed when compared with a few other top amplifiers. This is not a criticism, or a statement that the X150.5 was not accurate, just something that struck me over time. The X150.5 is an excellent amplifier that I will be sorry to see leave my sound system. And remember, if you wonder in the back of your mind if your loudspeakers are too inefficient, or your room too big, don’t forget that this is the baby in the X line. I can confidently recommend simply moving up the Pass Laboratories X series line to one of the X150.5’s more powerful siblings.