Solid State Power Amp Reviews

Because first impressions can be misleading, I believe that audio equipment should be auditioned over a long period of time. The Bryston power amplifiers did service for a good six months, driving a variety of loudspeakers. The amplifiers were run both single-ended and balanced, and, when used in a bi-amplified system, as both main and subwoofer amplifiers.

Comparison solid-state electronics were chosen for the listening sessions to match the Bryston gear in power ratings. Comparison amplifiers included two Mark Levinson 100Wpc dual-mono units: the discontinued No.27 and a new No.331.

Listening tests were carried out in two rooms. The first, my main listening area, is the most spacious, having an estimated volume of 5500ft³ and an effective room length of 51'. The main listening area is 26' long by 13' wide by 12' high, with an 8' by 4' doorway at the back of the room opening into a 25' by 15' kitchen. With only a single area rug, this space is a "live" listening environment. (This large room's exact dimensions, construction, contents, listening positions, rugs, windows, and bass modes were described in Vol.15 No.3, p.181.)

The Bryston and Levinson amplifiers drove, at different times, two different loudspeaker systems in this room: the main loudspeakers (Snell Reference Towers or Quad ESL-63s) with parallel bi-wired runs of Sumiko's OCOS speaker cable, or the systems' subwoofers (Snell SUB-1800s or Bag End S-18s) via Monster speaker cables. For each installation, the main drivers (Quads or Snells) were set up 6-8' from the back wall, with the subwoofers placed in the corners.

Other associated equipment used in the main listening room included a Day-Sequerra FM Reference tuner, a Rotel RHT-10 FM tuner, and a Linn Sondek LP12 turntable with Lingo Mod, Ittok arm, and Spectral moving-coil cartridge. CDs were played on a Krell MD-1 turntable driving an Audio Alchemy DTI jitter attenuator using a 75 ohm Silver Starlight digital coaxial cable. This unit fed either an Adcom GDA-700 D/A processor or an Audio Alchemy DDE v3.0 HDCD over its I²S bus. This converter was fitted with an RW-1 Remote Wand One.

A smaller, 12' by 12' second room was used for additional Bryston 3B-ST amplifier comparisons. This room is carpeted wall-to-wall, making it a less "live" listening environment than the larger room. Two modified Dahlquist DQ-10 loudspeakers (footnote 1) were set up at one end of the room on Dahlquist stands, driven from the amplifier under test (the Bryston 3B-ST or the Levinson No.27) by QED Qudos Profile B speaker cables. This system was controlled by the now-discontinued Krell KBL solid-state preamplifier. Sources included a Pioneer Elite F-93 FM tuner connected to a Magnum Dynalab ST-2 "whip" antenna and a Magnavox CDB650 CD player.—Larry Greenhill

Footnote 1: The Dahlquist DQ-10 was introduced about the same time (ca 1975) as the original Bryston 4B. Like many Brystons, my DQ-10s have survived the intervening decades, but not without modification: a Randall Research modification kit replaced the piezoelectric tweeter with a ribbon driver; all capacitors in the crossovers were replaced with polypropylene film types, with much guidance from Walt Jung; and, after the Bryston 3B-ST turned them into dust, Miller Sound re-coned both woofers. The good news is that these changes have increased the speakers' power-handling capacity, and made them faster and more dynamic. The bad news is a loss of the soundstage depth found in the stock factory design.—Larry Greenhill