A single-chassis phono stage pre-amplifier, the XP-15 represents a sophistication and maturation of both thinking and component evolution. Each new design of that evolution has brought a steady improvement in measured metrics and flexibility — greater accuracy in the RIAA curve, greater range of gain from 46db to 76db…and the list goes on. But more importantly the evolution has contributed to a more robust sonic image presented with improved resolution and additional sonic ease.
The XP-15 has a very accurate RIAA equalisation curve. This curve is accurate to better than 1/10 dB over 10 octaves. The accuracy of this curve does not vary with an adjustment change of gain or cartridge loading.
The XP-15 features gain adjustable from between 46dB and 76dB; a range sufficient to allow successful operation of not only high output
moving magnet cartridges, but also the lowest output moving coil cartridges without the use of an auxiliary step-up transformer.
By the early 1980’s audiophiles recognized that in general lower output moving coil cartridges were capable of retrieving more fine detail from record grooves than higher output cartridges, in many instances this was simply a case of having lower moving mass to excite in the electrical generator of the cartridge. Moving coils with less than a half dozen turns of the finest wire possible attached to the lightest and stiffest cantilevers were capable of accurately tracking musical passages that a few years before would have seemed impossible.
The cartridge makers had clearly taken a page from the automotive and motorcycle racing engineers who were doing everything in their
power to lower “un-sprung mass” in an effort to get tires to stay in intimate contact with rough terrain at high speeds. In both regards
the ability to accurately track the impossible is the ultimate goal….less moving mass attached to the suspension is a big part of the answer.
Unfortunately the active electronics that could extract signal at those low levels typically added noise. Step-up transformers generally addressed the noise issues, but frequently lost the very fine detail somewhere in the transformers iron core.
The XP-15 gives vinyl playback the gain structure we need and low noise figures we want. The ability to play extremely low output cartridges without a head transformer allows for a clarity with these cartridges that we’ve personally never experienced.
This extremely low noise / high gain structure of the XP-15 is capable of cleanly and quietly delivering in excess of 0.5V line level signal output with a phono cartridge input of 80 micro-volts. As far as we know these are the best performance figures in the industry for a phono-stage. Performance metrics aside this is beyond question the most user friendly and sonically enjoyable phono-stage that Pass Laboratories has ever offered.
Cartridge loading can be adjusted from a couple ohms to 47k-Ohms, with a parallel capacitance from 100 pF to 750 pF.