CES 2013: Conrad-Johnson

Bill Conrad and Lew Johnson of Conrad-Johnson were on hand to chat about their classic designs. I say “classic designs” because C-J has, at least for me, pretty much defined the high-end of audio for my entire adult life, and since I’m old, that makes ’em classic. Ahem. Anyway, they were here — and it was cool to see them as C-J doesn’t usually make a general practice of hitting the audio show circuit.

For those of you keeping track, I visited Conrad-Johnson last year and the now retired Ed showed me through the facility and let me take pictures. At that visit, I got to see a prototype stereo amp that is now in productions — the ART-SA amplifier — which went into production later that year. Lew Johnson took a few moments during that visit to wax enthusiastic about the new KT-120 vacuum tubes that C-J had switched over to from their traditional 6550 tubes, and with a sly grin used his hands to bracket out the performance gains — “waaaay better”, said he.

The company has continued the trend of moving to stereo amps — they’re cheaper to make and cheaper to sell than monos — and very recently announced the mid-tier LP125SA amp, an $8,250 stereo amp featuring the big, powerful, Kt-120 tubes. The LP125sa puts out 125watts per channel into 4 ohms, has an input impedance of 100,000 ohms, and weighs 85lbs. The aesthetic is also classic C-J — champagne-colored face plate, dark brown anodized sides and cover, and a single pair of non-inverting single-ended inputs.

The LP125sa audio circuit consists of three stages. The input signal is amplified by a single-ended triode amplifier designed for wide bandwidth. The signal is then direct coupled to a cathode coupled phase-inverter. This high current, triode phase-inverter stage provides a balanced, low impedance drive to the output stage. Output power is developed by two pairs of KT120s per channel, chosen for their excellent sonic character, high power, and reliability. The output tubes are operated in ultralinear configuration which offers a desirable combination of high power and low distortion. Massive output transformers with intricately interleaved windings afford extended bandpass and high phase linearity. A small amount (about 12 dB) of loop negative feedback reduces distortion and achieves a sufficiently high damping factor to control reactive loudspeaker systems.

For $10,000, the LP125SA is offered as an “Special Edition” package, “which incorporates CJD Teflon Capacitors and ultra high-performance metal foil resistors in strategic applications in the circuit.”

The demo consisted of the C-J top-line products, including their ART-SA amplifier, the GAT preamp and a HD-3 DAC, paired with Penaudio Sinfonietta loudspeakers. The sound here was exceptional, even at low levels, with a delicious relaxed quality and fine detail.