February 2002Conrad-Johnson Premier 18LS Preamplifier
by John Leosco
What kind of peanut butter do you like? Two options have been concocted by mankind: smooth and creamy, and the crunchy variety all loaded up with nuts. Although indispensable within a peanut butter cup, either choice sticks to my palate and masks the taste of good bread. Instead, cut a warm slab of Hawaiian sweetloaf straight from the bread machine, spread on a wad of artery-clogging butter, and Im in seventh heaven. Face it, sometimes light is right.
About 14 years ago, a Conrad-Johnson PV-5 found its way into my equipment rack and loyally served as my first audiophile-approved preamp. The all-tube unit certainly represented the smooth-and-creamy camp. As I recall, the bass was tubby, the midrange forward and lush, and the highs rolled off. The PV-5 was always musical, though, and mated well with some of the coarse solid-state amplifiers and CD players of the time.
More neutral alternatives were developed, and I ultimately settled on arguably the most transparent -- a passive line-stage preamp. The Melos SHA Gold, run passive, essentially places only a light-sensitive resistor and an input selector in the signal path. When the SHA Gold is used with powerful D/A output stages, I achieve crystalline clarity with little dynamic penalty. I've listened to many active line stages in my system, but the old Melos has staying power.
History can be an interesting subject, but these are different times. Many people are eating right, exercising regularly, and Conrad-Johnson just unveiled a new solid-state preamp. The Premier 18LS contains absolutely no vacuum tubes. C-J only uses the Premier moniker to denote their best line of electronics, and the 18LS is the first solid-state product to carry the Premier name. At $3495 USD, the 18LS is also the least-expensive Premier. Promising, eh? Lets see if the new kid relives the past or is a lean, mean fightin machine.
Less is more
The Premier line is constructed from fine components, including precision Vishay metal-foil resistors and proprietary polystyrene capacitors. Removing the 18LSs top cover revealed a simple, well-laid-out circuit on a single large board. Field-effect transistors (FETs) were selected for the active devices in the Premier 18LS because, like tubes, they produce little odd-order harmonic distortion. Symmetrical n- and p-channel FETs achieve low distortion with zero negative feedback, so none is used, reportedly resulting in improved transient response. The single active stage provides 22dB of gain and inverts signal polarity. Volume and balance adjustments are ultimately microprocessor-selected resistor combinations, 100 steps per channel with approximately .7dB between each discrete jump. No potentiometers for this baby, and I must say completely repeatable level settings are nice.
Up front, the thick faceplate is finished in contrasting matte and beautiful bright gold finishes. When surrounded by black boxes, the Premier 18LS gleams like a gem among lumps of coal. Six shiny gold buttons select among sources and processor loops, adjust volume level, and mute or power down the unit (by either tapping or holding the mute button). Small orange-colored lights indicate the active source. Three round lenses, arranged like the finger holes of a bowling ball, legibly display left- and right-channel levels, with the lower circle housing the sensor for the remote control. The heavy, milled aluminum remote duplicates all front-panel functions and adds balance control.
The whole package measures 19"W x 3.8"H x 15.4"D, weighs 16 pounds, and would only fit on the top shelf of my Solidsteel equipment rack. Around back, five pairs of single-ended inputs (labeled Ph/Aux 1, Tuner, CD, Video, and Aux 2), two processor loops, and one pair of outputs terminate via solid RCA jacks. The first processor loop (EPL) is of conventional design, while the second (Theater) sets the volume controls to unity gain. An external surround-sound processor could control level with Theater selected, handy for use with a home-theater setup. An IEC power socket allows for use of after-market power cords. Absolute polarity reversal, preferably on the remote control, was the only feature I missed on this well-engineered preamplifier.
Finding all single-ended electronics in the Premier 18LS led me to ask Lew Johnson about the Conrad-Johnson design philosophy. He said that good parts cost money. At every price point, even up to and including the statement ART preamplifier, utilizing premium components gives more sonic benefit than providing duplicate circuitry to support fully balanced operation.
My all-single-ended system consists of a PS Audio Lambda CD transport feeding either a Dodson Audio DA-217 Mk IID or a Theta DS Pro Basic IIIa processor through an Illuminations D-60 digital interconnect. Amplifiers were an Ayre V-1 and a Krell KSA-150 powering B&W Nautilus 801 loudspeakers. AudioQuest Diamond and Opal interconnects linked the components. Speaker cables were Synergistic Research Resolution Reference and Signature #2, and JPS Labs Superconductor+ Petite. An API Power Wedge 116 conditioned AC power to the front-end. Electrons to the amps were raw and straight from the wall.
The 18LS owners manual specifies a preamp output impedance of 200 ohms and recommends the use of an amplifier with an input impedance of 20k ohms or higher. I tried different amplifiers, including the complex load of the Ayre and Krell hooked in parallel, and the 18LSs character remained consistent throughout. The Premier 18LS should be compatible with many amps.
I hear music
First and foremost, music from the Premier 18LS was highly enjoyable. From Janet Jackson to Bill Evans, Nirvana to James Taylor, I was drawn into my listening chair and compelled to spin disc after disc. Like melted butter, the 18LS is not clear as water and casts a light, distinct flavor over the sound as it passes through. And what a delectable sensation it is. The feeling is of tranquility and composure, freedom from anxiety and tension. Digital sources can come across as edgy and aggressive. This C-J line stage subtly removes some of the bite, providing a relaxed, rewarding experience with every CD played.
Now, dont get the impression that the Premier 18LS is inaccurate; tonally it is quite neutral and extended. Sorry, the butter analogy was too thick -- think leaner and better for you, like a drop of olive oil. Strong, full bass response comes with good control, and high frequencies shine with absolutely no hardness. And the midrange? Oh, the midrange, is special, not overly elaborate but intricate and rich in detail.
Ive used Anita Bakers Rapture [Elektra 9 60444-2] for years as a reference. A huge, powerful window displays the busy mix, with Ms. Baker front and center. When compared to todays digital best, this 1986 release cant compete, but Im very familiar with it, which is the #1 criterion for a reference disc (Elektra, please remaster this one). The Premier 18LS clearly resolves Bakers soulful vocals, squeezing out every bit of depth and presence, her aura clearly differentiated from the supporting cast. Excellent. And when the peaks get a little strident, and they do, my eardrums say, "Thank you" to the Premier 18LS and its easy-going way with music. Every track on Rapture is supported by a solid foundation, and top to bottom, the Premier 18LS impresses.
Piano is always a good test for midrange detail. I pulled out a couple samples from Mark Levinson Live Recordings at Red Rose Music [RRM 01] and Dick Hyman Plays Fats Waller [Reference Recordings RR-33CD] on which unaccompanied piano sounded very real, with truth in its timbre. Individual keystrokes created semi-focused fundamental tones surrounded by smooth, rich harmonics. Played en masse, the strings blended into a vivid, life-sized panorama. Loads of resonant body, especially in the mid-to-lower registers, defined the final dimension. A slight reduction in upper-octave sparkle deviated from perfection, but this did not detract from the performance. Ive never heard solo piano sound better on my system than with the Premier 18LS in use.
Active vs. passive
Needless to say, I was anxious to pit the Conrad-Johnson Premier 18LS against my long-term reference, the passive Melos SHA Gold. All head-to-head comparisons were completed with matched levels, and I just about wore out my rug making the necessary adjustments (mostly the fault of the Melos and its inconsistent volume vs. balance tracking).
One difference wasnt subtle, and that was in the bass arena. Consistently the Premier 18LS outgunned the SHA with more prominent bass lines, but it was never overbearing and always in control. The Melos passed leaner bass with slightly more slam, so my preference depended on which disc was in the transport. With the Premier 18LS, bowed double bass gave a woody, reverberant sound erupting with many more overtones, probably a function of its stunning midrange and not indicative of any low-register prowess.
Well-recorded small-group jazz proved valuable in exposing finer distinctions. The three superb Hollywood cuts from Miles Davis Seven Steps to Heaven [Columbia CK 48827] prove why he is considered an important trumpet player and not just a great bandleader. His horn emerges from center stage with a halo of air around it. The notes project outward with incredible dynamics, yet every note contains within it subtle inflections and modulations. You can almost see the spit on Miles lips and feel the air from his trumpet on your cheeks. Through the Premier 18LS, his signature muted horn was larger and had rounder edges, the trumpets air blending thoroughly with the cymbals and piano. The Melos SHA Gold gave a more pinpoint, focused view, with each instrument mostly confined to its own space.
Closely miked drums disclosed minor deficiencies of the Premier 18LS. The impact of sticks striking taut drum skins snapped with a slightly muted crack, and rim shots had less pop. Cymbals, brushed or tapped, contained plenty of sheen, appearing as if all the harmonics were intact. Missing was the last bit of air around the cymbals during their ring-down, a detail obvious only when the Premier 18LS is compared to the Melos SHA Gold.
A different perspective came to light while playing Mahlers Symphony No.1 [Phillips 422 329-2] with the Boston Symphony Orchestra conducted by Seiji Ozawa.
With the Premier 18LS, the brass was a little brassier and the strings silky smooth. But the big difference was in the grand scheme, a perception of spatial qualities the Melos preamp just couldnt communicate. The whole stage was more three-dimensional, more real. Despite the large image size, the entire production blended together as a whole. I think continuity is the right word, like a unification of parts into one.
My system isnt wimpy by any means, but in terms of large-scale dynamics, the Melos is a restriction. Aware of its limitations, I have become accustomed to certain outcomes. With the Premier in the chain, Ozawas interpretation of Mahlers 1st began, and during the first movement, I was still trying to get the volume set just right. What sweet sound, I thought as my thumb increased the level. With no apparent hardness, I juiced it up a bit higher. Then, bang! The climax hit at about the 14-minute mark, and I actually felt the concussion blast against my chest. Whoa!
On a hot day, a cup of olive oil wont quench your thirst. Pouring water on bread only makes it soggy. Obvious concepts, I know, but thats how these two very different preamplifiers compare, which is to say that they dont. The CD in the player, the system the preamp is connected to, and the sonic priorities of the listener will ultimately determine which one is closer to right. With that said, after spending a couple of months playing around, I sure enjoyed listening to a lot of my music through the Premier 18LS.
The Premier 18LS is a solid-state Conrad-Johnson for the new millennium, successfully integrating remote-control convenience with great sound. Led by a harmonically rich midrange and solid overall performance, sonically the Premier 18LS's strengths are considerable and its imperfections minor and easy to ignore. To my ears, the Premier 18LS only gave away a bit of extension at the absolute frequency extremes and some transient impact.
More importantly, the Premier 18LS conveys the essence of music. Continuity, I think I called it, but things just sounded right with the Premier 18LS. I know that statement mirrors the Conrad-Johnson advertising slogan, and in this case its true. If youre not totally sold on the merits of fully balanced operation (I'm not), give the Premier 18LS a listen. Its a beauty to behold and a joy to use.
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