Maximum gain for the moving-coil input is 72dB, and 57dB for the moving-magnet input. The additional 15dB of gain for moving-coil carts is achieved using Lundahl step-up transformers. The moving-magnet inputs bypass the step-up transformer and have a fixed 47k-ohm load.
The design allows users to change resistive (mm) and capacitive (mc) loading, as well as adjust gain, safely “on-the-fly” from the front panel. Front-panel controls also allow selection of either the mm or mc input, as well as stereo or mono operation. Output signal selection (RCA single-ended or XLR balanced) and absolute-phase inversion may be implemented at any time using rear-panel toggle-switches. However, neither toggle-switch is demarcated for which position (up or down) represents which selection, RCA or XLR output, or 0 degrees or 180 degrees; nor are the default settings mentioned in the manual. I had to write to Dan to learn that in the case of the phase switch, down would be off, or 0 degrees. While this omission is an inconvenient oversight that could easily be addressed in future iterations, I understand the decision not to destroy the strong symmetry of the front panel by locating the switches there.
Starting with the foundation, bass is tight, solid, and rendered with exceptionally well-defined pitch. Timbre throughout the lower registers is pure, with authentic tone and texture. The lowest three octaves are offered with authoritative weight, impact, and impressive slam when such information exists on the recording, with no demonstrable sense of softening or slurring.
Midrange tone and texture are among the PH 150 Reference’s great accomplishments. Everything from human voices, to horns, to pianos and strings is presented with purity, tonal accuracy, and almost effortless resolution.
Treble is pure, clean, and detailed, and perhaps most importantly, highly resolved. No, that is not “code” for overly energetic, etched, hard, or glaring. Rather, the PH 150 is truly detailed in the high end, with none of those traits that can be mistakenly interpreted as “resolution” in lesser gear. The PH 150’s almost magical presentation in the top octaves extends smoothly beyond the audible. One delightful result is a sense of “air” to spare, though never at the cost of detail or a softening of focus.
While it may not be the last word in resolution or transparency compared to über units such as the Audio Research Reference Phono 10, the D’Agostino Momentum Phonostage, or the Soulution 750 (all in the $30,000+ neighborhood), the PH 150 has the ability to serve up some of the most precise leading-edge transients I’ve heard. And its remarkably detailed view into the performance is full-bodied, as well.
Included among its other numerous strengths are an exceptionally low noise floor, the ability to portray bold and vivid tone, remarkably accurate staging and spatial cues, and wildly dynamic expressiveness. Its ability to capture silences, both with nothing tracking at all and between cuts, is remarkably reminiscent of the quietest noise floors I’ve experienced from phonostages costing considerably more. I cannot recall any tube phonostage I’ve heard that is quieter. As such, music through the PH 150 Reference is allowed to emerge or erupt from one of the blackest backgrounds that a phonostage can offer.
Horns, ranging from solos by Miles Davis or Wayne Shorter, through smaller rhythm sections like those of Chicago or Big Bad Voodoo Daddy, to the brass sections of symphony orchestras, have an incontestable purity of timbre, with a seemingly effortless conveyance of their signature brassy character. They are also imaged in realistic size and with stable location.
This ability to accurately express vibrancy of tone, with proper color and texture, and to realistically render body and instrumental bloom, with none of the euphonic warmth of less ambitious valve-only designs is again on par with much more expensive phonostages. In this particular regard, it quite possibly rivals my current reference, the Dynamic Sounds Associates Phono II.
As touched on, the PH 150’s ability to reveal spatial information—ranging from that on an intimate four-piece jazz combo recording like Dmitri Matheny’s 2014 Sagebrush Rebellion [Papillion/Blueport], to the vast acoustic of a large-scale orchestral work like Beethoven’s Ninth Symphony—with realistic size and accurate and stable individual voice placement is exceptional. I believe its inspired performance in this quarter is a result of the synergy of its remarkably low noise floor, superb resolving capability, and see-through transparency. I freely admit that staging is a hot button for me, and the PH 150 Reference surpassed even my relatively high expectations in this regard.