Sophia II's and Pass Labs etc

Beside current bias can anyone think of other differences between models of the XA.5 line? A theory is that given the XA.5 design, current bias level has its peak performance at certain marker. People at Pass Labs don't get into it because the reason why is not well understood. Just thinking out loud here.

Hi Toffeng,

I don't own the Sophia II's, but I am currently listening to a few different combination's of gear driving my Avalon Opus speakers (full range speakers at 87 dB efficiency in a rather large room). Among the amps and preamps are the Pass X250.5, the Pass XA100.5, the Pass XP-10 preamp, and the H2O Audio Fire preamp. I previously auditioned the ARC LS26 preamp, which I thought was strident in the upper midrange and rolled off in lowest frequencies when combined with the Pass X250.5. I also auditioned the Cary SLP05 with the X250.5, which sounded very nice although a bit colored (in a good way) in the midrange.

Different people respond to different aspects of sound quality, and components that work great in some systems don't work well in others. With this in mind I don't like giving recommendations as much as describing what works well in my system. That being said, the XA100.5 monos are proving to be really outstanding sounding amplifiers. They are powerful and delicate at the same time. They are warm with a full midrange, but no midbass bloat and very nice extension in both the upper and lower frequencies. Their full bodied presentation and power, along with their lack of distortion and noise results in an exquisitely beautiful sound.

Regarding preamps, my favorite with the Pass amps is the H2O Audio Fire. I recently described this preamp in a different thread so I don't want to repeat myself here other than to say it mates very well with the XA100.5. Another contributor to this thread will be trying one out with his XA100.5 amps, so maybe he can chime in with his results after he's listened to it for a while. The drawback is that it is a big two box affair that will be expensive to ship to Norway from the U.S., but it is also not as expensive as the others you have been thinking about.

P.S. I will be traveling to Norway in August. I've never been, so please let me know if you have any advice for areas that are not to be missed.

Good luck with your search,
Alan

I called Pass Labs describing the Audigon discussion. His answer about "sweet spot" is just what Peterayer said. It's a personal taste on value based on price and whatever else the person think is important. It has nothing to do with design. Although bias and power supply size are changed as you go up the power rating, the design is the same. Basically you want bigger amp as you have more demanding speakers. Gee, for a moment I thought I bought the less desirable model of the XA.5 line.

I used to have Watt Puppy 6s with a Pass X350 and found it a good match, especially in the bass, which was natural and listenable and well integrated. In showrooms, I also thought the WP6s paired well with Levinson 33Hs and BAT amps. Hope this helps, even though these were not Sophias.

For the original poster's benefit:

I would recommend the XA100.5, but not the XP20. Although I voiced my opinion clearly for the XA30.5 with the Sophia II's, I think compared to the rest of your system, the XA100.5s would be the best fit. I think you would appreciate the difference between an XA30.5 and the mono XA100.5s and you would be willing to pay for the improvements. In my situation, the XA30.5 fit the bill just fine both financially and sonically (and it allowed me to purchase a tube amp to swap out during winter months or when the mood was right). The XP20 is very good, but you really should pair the XA.5 series with a tube preamp as it will only add to and enhance the sonic purity of timbers/harmonics you get from the XA.5 series.

Hope this helps.