Phono Preamp Reviews

Manufacturer's Comment

Thanks to Tom and John for a detailed and thorough review of Brilliance. Tom's comment, "Because it imposes so little of its own character on music, it allowed the character of each cartridge to shine through," tells us we met our design goal of playback transparency, as in the proverbial "wire with gain."

John's measurements confirm ours. To add some insight, making a clean, accurate phono stage with selectable gain ranging from 30dB to 70dB (factoring in RIAA, that's 90dB in the bass!) is not easy. To do it, we designed a unique, custom op-amp and input stage with fixed-current gain of 50dB, which has better performance as the input level goes down. John's distortion plots were done with MM signal levels; the THD, IMD, and overload margin he measured, while good, can be considered "worst case." Those numbers improve with lower input levels and at higher gain.

John also noted that "the unbalanced inputs inverted polarity." Our design preserves polarity in all cases. The unit Tom tested was the first unit to leave our premises; it is possible that the RCA connectors are reverse-wired.

John wrote, "Peculiarly, the unbalanced input impedances were close to half the values set." For this review this primarily affected the MM input, at 23.5k ohms instead of 47k ohms, because for MC, 20 ohms through 400 ohms were used in balanced mode. We are aware of this flaw and have a circuit correction for it.

Finally, John wrote: "I just wish the setting of that recessed pushbutton on the rear panel was easier to see." This switch must be a hardware switch. We have a design change ready to replace the pushbutton with a relay and control it from the Wi-Fi interface in a future revision. In the meantime, only reviewers push that button more than once or twice. :-)—Brian Lowe, founder and engineer Belleson