Twochannel Reference Build — Warm-Musical Vinyl Separates

Aimed at a committed vinyl listener in a treated two-channel room who wants a true separates analog chain rather than an integrated. It prioritizes midrange body and a low front-end noise floor over format flexibility.

This is a separates vinyl front end built around a single load-bearing pairing: the tube power amplifier's matched output taps and the loudspeaker's 4-ohm nominal impedance. The Sonus Faber draws 92dB/W/m and dips to a nominal 4 ohms, with a first-order crossover attenuated at 200Hz and 2.5kHz that leaves the impedance curve relatively benign. The Audio Research monoblocks offer dedicated 4, 8, and 16-ohm output taps; running the 4-ohm tap into this load keeps the source impedance the tubes see consistent across the band, which preserves the speaker's tonal balance rather than letting a fixed-tap mismatch tilt the upper midrange. With 400 watts available per channel against a 92dB sensitivity, the amplifier idles in its comfortable region at typical listening levels and the speaker's 30-to-300-watt power handling is never approached, so dynamic swings on orchestral material arrive without the amplifier clipping or the drivers compressing. The analog chain is gain-staged deliberately. A low-output moving-coil cartridge of roughly 0.3 to 0.5mV feeds the phono stage, whose selectable moving-coil gain spans +60 to +72dB at 1kHz with loading adjustable up to 470 ohms, so the cartridge can be matched precisely rather than approximated. That stage's 200-ohm output impedance and roughly 0.5V output drive the line preamplifier's 120k-ohm balanced input with margin to spare; the preamplifier in turn presents a 600-ohm balanced output into the amplifier's 200k-ohm input, a source-to-load ratio that keeps cable interactions and high-frequency rolloff negligible across reasonable interconnect lengths. The air-bearing turntable with vacuum hold-down lowers the noise floor that the high-gain phono stage would otherwise amplify, which is the reason a quiet front end matters more here than in a line-level system. What the listener hears is body and continuousness through the midband: voices and massed strings have weight in the lower midrange without thickening, and the first-order crossover's phase behavior keeps image height stable. This expresses the warm-musical intent through engineering choice rather than coloration. The character is load-bearing in the amplifier-to-speaker interface and in the cartridge-to-phono match; substitute a fixed-tap solid-state amplifier and the impedance interaction with the 4-ohm load shifts the tonal balance, and the deliberate analog gain structure is what the system is built to exploit. Both interfaces — cartridge-to-phono and amplifier-to-speaker — fix the limit that everything downstream has to live within.

In-room, the speakers extend to roughly 24Hz — enough weight for acoustic bass and full-scale dynamics, though the deepest pipe-organ and bass-synth fundamentals fall away below that, and the system ships without a subwoofer. The tube power amplifiers run warm, draw 260 watts at idle each, and require periodic bias attention and eventual retubing, so this is not a low-maintenance or low-heat system. It is also single-source by design: there is no digital playback in this configuration, so streaming or disc replay would require adding a converter and an input the preamplifier can accommodate. The 4-ohm tap choice optimizes for this speaker and would need revisiting for a higher-impedance load.

• 01

  Swap REF160M MkII → Reference 150 SE (−$30,000)

  Swap the monoblock pair for a single stereo tube amplifier of 150 watts per channel. This lowers cost and footprint and keeps the tube character and the 4-ohm output tap, at the expense of the channel-to-channel isolation and current headroom the monoblocks provide on large dynamic peaks. This pairing shows up frequently in community systems alongside the monoblocks.

• 02

  Swap H7000 → Reference Phono 2 SE (−$6,805)

  Substitute a tube phono stage with selectable 51 to 74dB gain and switchable 50-to-1000-ohm loading, unifying the phono and line stages under one design philosophy. It reduces cost and offers per-record RIAA, Columbia, and Decca equalization curves, but gives up the transformer-coupled moving-coil input topology of the original phono stage, which some low-output cartridges prefer.