Yes the Pass X-1 is definitely better than the Aleph P, but that is not saying a whole lot. I am a Pass Aleph amplifier owner and a clear Pass bigot when it comes to the Aleph amps and I have respect for the X series amps, but, IMO, the X-1 clearly doesn't measure up to the best tube preamps. According to Pass, you have to leave it on all the time in order for it to sound its best and I've heard that while it sounds better, it never achieves that A-1 sound which can be had with some of the best tube equipment. In my audition with the Pass X-1 and the X-350, I heard an overly heavy bass and no midrange sweetness. Certain musical passages were overly bright. If you compare it to the Aleph P, yes it sounds great, because this wasn't an exceptional preamp at all. I completely agree with Jtinn and Topkat. Pass Labs has a great reputation for designing amplifiers, but that reputation does not carry over to preamplifiers.
