I recently replaced the Pass Labs Xono phono stage that was purchased in November of 2006. I had some concerns about diminishing returns since the XP-25 retails for 2.5X the price of the Xono. I found that the XP-25 really is that much better than the Xono:
1. Much More holographic.
2. More detailed.
3. Heavier images.
4. More depth and layering.
5. More clarity.
Whether is it worth the cost premium over the already excellent Xono depends on how much someone values improvements in stereophonic attributes such as image layering, image weight and sonic realism.
The dealer allowed a two week trial period and a generous trade-in allowance. I did not need the two week trial because the sonic improvements were immediately and plainly obvious. The Xono was shipped back to the dealer for trade in credit the day after I received the XP-25. This was after staying up until 4 am going through my record collection.
In addition to the sonic improvements, I appreciate the XP-25's ergonomic improvements that have brought loading and gain adjustments to the front panel. The Xono's cartridge loading and gain adjustments were made with internal switches after taking the top cover off. Low noise internal switches were used to avoid introducing "noisy" rotary switches in the signal path. For people with multiple tonearms and multiple cartridges, this was a major inconvenience. There have been some recent significant improvements in rotary switching devices that allowed their use without compromising noise performance over what would occur with internal switches.
The only thing I don't like about the XP-25 is the control chassis' increased sensitivity to magnetic fields. As shown in figure 6, the XP-25's control chassis sits above the left side Parasound Halo JC 1 monoblock amplifier. The JC 1 causes a faint hum in both channels. I use the maximum gain setting of 76 dB and the hum cannot be heard at the listening position.
Figure 1. My Pass Labs gear always arrives in a big box with plenty of stickers and security tape announcing the contents. I'd prefer a plain brown box with "fragile" stickers.
Figure 2. Pass Labs XP-25 control chassis (top) and power supply chassis.
Figure 3. The XP-25 is not a refinement of the Xono phono stage. It is a completely new design.
Figure 4. The XP-25 has inputs for two tonearms compared to the Xono's one tonearm input.
Figure 5. Don't forget to light the fuse! The stock tin fuse was replaced with an audio grade HiFi Tuning Supreme fuse.
Installing a HiFi Tuning fuse in the XP-25 did not bring the degree of improvements in clarity, sound stage dimensions and imaging as it did with the Xono. This was not surprising since the XP-25 has better noise performance than the Xono. As with the Xono, the best sound was heard with the fuse arrow pointing away from the point at which AC enters the unit. In the case of the Xono and XP-25, this point is the rear end (the end closest to the rear of the unit) of the fuse receptacle. The point of AC entry can be determined by testing for continuity between the "line" IEC socket blade and both ends of the fuse receptacle.
Figure 6. The large silver thing between the JC 1 amps is a PS Audio PerfectWave P10 AC regenerator (review coming).
Figure 7. The P10 replaced a PS Audio Power Plant Premier.
Figure 8. The P10 features Power Port Premier receptacles. People complained bitterly that the Power Plant Premier did not offer Power Port Premier receptacles.
Figure 9. You're pretty, yet so barbaric. I wish I knew how to quit you...but I won't be able to until all my favorite records are transferred to hi-rez digital. Who would have thought that Such Good Sound could come from dragging a rock through plastic grooves?