Preamplifiers

conrad-johnson Classic Vacuum Tube Preamplifier with Phono Stage

ARTICLE INDEX


Introduction

conrad-johnson (lower case c and j) was formed in the mid-seventies, shortly after I became seriously interested in audio gear. I'm sure the two events were entirely unrelated. Their first product, a preamplifier, was immediately recognized as "state of the art," and so their storied history began. I encourage you to visit their website for more details. There, they provide a long list of products that have been reviewed as "Best of Class", and even "Best in the World." The Classic Preamplifier is the least expensive line-stage (the phono stage is optional) in their formidable product line. Both stages are zero-feedback circuits. The phono section uses two triode amplifiers separated by a passive RIAA equalization network. The second triode amplifier is direct coupled to a high-current output stage. The line-level section has a single triode amplifier also direct coupled to a high-current output stage. I considered using the descriptor 'entry-level,' but that would hardly do the Classic justice. As I immediately discovered, there is nothing entry-level about the Classic, except for the incredible price-to-performance ratio.

Specifications

  • Classic Line Stage:
  • Design: Stereo Vacuum Tube
  • Gain: 22 dB
  • Maximum Output: 9.5 VRMS
  • THD: less than 0.15%
  • MFR: 2 Hz to more than 100 kHz
  • S/N: -98 dB relative to 2.5 V output
  • Tube Complement: 2 x M8080
  • Optional Phono Stage:
  • Design: Vacuum Tube
  • Gain: 54 dB
  • Phono Equalization: within ± 0.25 dB of RIAA standard
  • S/N: Phono Stage 80 dB relative to 10 mV input
  • Tube Complement: 3 x 12AX7
  • Dimensions: 3.6" H x 19" W x 13.6" D
  • Weight: 14 Pounds
  • MSRP: $1,750 ($2,500 with Phono Stage)
  • conradjohnson Designs

Design

Build Quality/Controls/Connections

Out of the box (well protected in a custom foam insert) I immediately recognized the cut-above build quality of the Classic. It's a looker too, that is if you appreciate an understated simplicity, and the golden champagne hue of its fascia.

conrad-johnson Classic Vacuum-Tube Preamplifier with Phono Stage

Here is another view:

It is understated, yet elegant. Speaking of fascia, the face and side panels look to be milled out of solid aluminum. The face is ¼ inch solid, brushed aluminum, and the sides are about 3/16th. The main chassis seems to be crafted of heavier gauge steel than your garden variety mass-market enclosure. The controls consist of an input selection dial, a volume control, and a power switch. Simple enough… The input selector clicks into place confidently, the volume control is very well damped, and the power toggle is rock-solid. The back panel is nearly as uncomplicated. There are 2 sets of pre-outs, a tape out, and 5 inputs. The auxiliary input acts as the phono input when the optional phono stage is included (as it was in the review sample). All inputs and outputs are gold plated RCA. There is a 45 second warm-up delay at startup.

conrad-johnson Classic Vacuum-Tube Preamplifier with Phono Stage


Sound Quality

Does the Classic fulfill its legacy? I was so taken aback when I first fired-up this fine piece that I couldn't keep it to myself. I was giddy. Where's the fun in keeping something that evokes such emotion to one's self? Not to mention, I wanted to make sure that I was hearing what I was hearing. Huh? Anyway, I called in my trusty audiophile-in-waiting son Colin to take a quick listen. I sat him down in the prime listening spot of our home theater. Mind you, he's never experienced anything other than multi-channel music and movies in this space. The first thing I asked him was "how many speakers are playing?" [We have a 7.2 system.] He listened intently for a few minutes. Finally, his pristine hearing confirmed what I knew that I heard. He pointed to the L/C/R speakers, the two side surrounds, the subs, and just as I had heard, he then pointed to a space above each of the L/R mains, and a space toward the top of the side walls, just out from the mains. But, that's 9.2; we only have 5.2 speakers in that space. Besides, this is a stereo preamp. How can this be?


Setup

"conrad-johnson It just sounds right"

Dimension in terms not only of width, but height, depth, and pinpoint placement do not have to be 'manufactured' after the fact. If they exist in the source material they can be conveyed in all their glory through just 2 speakers. The Classic does just that. It conveys the realism and/or intent in the source material. Whether that is a small club, an intimate theater, or a large hall, the Classic didn't need help from some Digital Signal Processor ambience mode to place me at the performance.

What's the big deal? Virtually every home theater receiver/processor has an analog mode. The big deal is that they generally don't offer the same pure, unadulterated signal path as the best analog gear, in this case the Classic. Based on my own very recent experience, even some very expensive processors fall short when it comes to analog pass-through. They have relays, capacitors, and various and sundry electronic circuits along the way. As good as those parts may be, each extracts a tiny fraction of flesh. Combined, those fractions can become pounds. The Classic extracts nothing. It adds nothing. It does so gloriously.

As a newer member of the Secrets Team I continue to learn some valuable lessons. Thanks to the Secrets Editorial Team and Lew Johnson (of conrad-johnson) for their patience. I appreciated the Classic so much that I played way too much (material). I pulled out all stops, and ended up listening to CDs and LPs that I hadn't listened to in years; that in and of itself should be an indication of my opinion of the Classic. I even pulled out 2 additional sets of speakers. I had 20 pages of notes. I needed to go back and narrow my impressions down from just a few of my favorites. That allowed me to play even more. By the way, throughout this review I promise not to use the word aplomb.


In Use

conrad-johnson Classic Vacuum-Tube Preamplifier with Phono Stage



I cued up Luka Bloom's Turf CD to determine how the Classic presents basic acoustic music, in this case a male voice and lone acoustic guitar. Perhaps more appropriately, what I discovered is how Luka himself (along with his recording engineer) presented the music. On the track "True Blue," the presentation of Luka's voice was fluid. His vocals and guitar were firmly anchored slightly right of center, and that placement never wavered. The pluck and decay of the strings and movement of his fingers on the fret board were all presented as clearly and naturally as if he were in the room. The experience was not like listening to the recording, rather, it was like listening to the performance. Track 11, "The Fertile Rock" starts out with a choral intro sung by an audience at the Tivoli, a club in Utrecht, Holland. The voices were naturally layered, and individually distinguishable through the Classic. The mix had the choral emanating from behind the artist, and it was utterly convincing in dimension. The soundstage was every bit as deep as it was wide.

conrad-johnson Classic Vacuum-Tube Preamplifier with Phono Stage

I wouldn't characterize Annie Lenox's Diva as basic music. It's full of synth and heavy bass lines common to '80s and early '90s pop. Regardless, it's well recorded. The track "Why" starts out with synth and heavy, bass, followed by a wonderfully layered harmony anchored by Annie's voice. The bass is taught and tuneful, and vocals are exceptionally clear. The tracks on this CD present an immense soundstage, and the Classic applies gain and otherwise passes it through completely unadulterated. The track "Legend In My Living Room" has several passages where sound pans from one side to the other. The effect through the Classic is completely immersing. Sound not only pans across the soundstage, but it pans well above the speakers, flows down the side walls high and low, and even behind the listener. It creates a holographic soundstage, the likes of which compare to better multi-channel high resolution surround recordings, in this case through just 2 channels.

conrad-johnson Classic Vacuum-Tube Preamplifier with Phono Stage



On Dave Grusin and Lee Ritenour's Harlequin CD, the piano key strikes and guitar plucks on the title track are presented like the finest life-like portrait. Ivan Lins' vocals shine through like the glorious instrument that it is. On percussion instruments, one can distinguish between sticks and brushes, between high hats and cymbals. There was air in abundance. Bells sound like bells and blocks sound like blocks. No guesswork is required. There is no loss of upper detail through this tube based preamp. The Classic doesn't restrict the timing, rhythm and pace of the faster tracks. Lee Ritenour's guitar work on "San Ysidro" and Silent Message" strikes fast and decays naturally, as does Dave Grusin's piano on "Silent Message." Everything flows through the Classic with complete truth and ease.

Ronnie Jordan's "Seeing Is Believing" from A Brighter Day throws a 3 dimensional holographic soundstage. The natural resonance of Ronnie's acoustic guitar and Ian Martin's bass are presented with superb texture, weight and depth. On Elton John's "Come Down In Time" from the Tumbleweed Connection SACD, the acoustic harp may as well be in the room. The acoustic guitar intro on "Love Song" presents well beyond the plane of the speakers, and the Classic moves out of the way. I could imagine myself in a smoke filled jazz club listening to Jay McShann's What A Wonderful World SACD. The piano, cymbals and upright bass on "Just For You" were immediate and crystalline in their texture and clarity. "Yogi's Dream" from Bob James' Ivory Coast delivers up Bob's Steinway, Omar Hakim's percussion, and Kirk Whalum's sax with the perfect edge. There were no electronically induced artificial edges on cymbal crashes or hard hitting sax blasts. They were just right. I dusted off some Poco, in this case Crazy Eyes. Poco mixed banjos and acoustic guitars with orchestras before it became more mainstream with the Eagles. Richie Furay's and Timothy B. Schmit's distinct vocals underpin the harmonies on the title track. The harmonies are richly layered, the banjo pickin' is clean and fast, and the orchestra is well delineated. However, the pieces and parts aren't very well integrated in this recording. It sounds like a bunch of separate tracks mashed together. I found that this CD was better left to far less resolving gear.

conrad-johnson Classic Vacuum-Tube Preamplifier with Phono Stage

The Stereo Fidelity LP Miles Davis Kind of Blue took me right back into that smoke filled jazz club. This was a smaller, more intimate club. This was a different time. The Classic phono stage resolves very well. This is considered true reference vinyl. I compared my reference outboard phono preamp with the phono stage in the Classic. The results were predictable in that the phono stage performed admirably. It delivered slightly less weight in the lower octaves than my thousand dollar stand alone unit, but it delivered all of the texture and detail, if not ever so slightly more in the upper-middle frequencies.

Duffy's Rockferry was an eye opener. I could hear detail on the LP through the Classic's phono stage that I could not discern on the CD played through my reference system. She has a unique, bluesy texture to her voice. The LP also uncovered more nasality, particularly on certain songs. LPs shine in the middle frequencies, in this case presenting a subtle tonal quality and texture that couldn't be discerned on CD. I expected more from the limited pressing of Steely Dan's Aja by Cisco Music. Still, the Classic neither improves upon, nor hides anything in the source.

Madeleine Peyroux's Careless Love on MoFi revealed some of the best attributes of vinyl. The simple arrangements backing her classic voice came through as pristine as they were recorded. Every nuance, the brush on a cymbal, the stick on a snare, the pluck on the bass comes through with an uncanny natural fidelity. Much like Duffy, you hear her taking a breath between words, and there is no hint of electronically exaggerated sibilance. The Manhattan Transfer LP Brasil features several of the same songs found on Grusin and Ritenour's Harlequin. Here, they are presented in English. The rhythm and pace is a little quicker, the arrangements more complex. The Classic phono stage exquisitely resolves each supple layer of detail.


Conclusions

The conrad-johnson Classic is an exceptionally well executed line-stage. As an optional bonus, it can be fitted with a fantastic phono preamp as well. Except to adjust the volume higher (and, you'll want to do that often), you'd never know it was there; it simply vanishes. It becomes a transparent conduit to the source. That's exactly what a good line-stage is supposed to do. Combined with a good player, amp and speakers, the Classic transcends any medium. It places you in the event, whether that's in front of a stage, or in the club or recording studio. It reminded me why music matters. It's simple, really. Do yourself a favor and audition the Classic.

  • Reference Gear:
  • Sources: Pioneer Elite BDP 05 FD CD player; Marantz TT-15S1 Reference Turntable w/Clearaudio Virtuoso Cartridge
  • Phono Preamp: Graham Slee Era Gold V
  • Preamp/Processor: Marantz AV8003
  • Amplification: Butler Audio TDB 2250 Vacuum Tube Driven Stereo Amplifier
  • Speakers: Quad 22L2; Usher Audio Be-718 and Usher S-520 Speakers