by Roy Harris
I own an Audio Note CD player. It has given me 15 years of trouble-free service. A friend and co-member of a local audio club informed me that he was going to receive a tube dac, tube phono stage and the L3 line stage from the Canadian distributor of Audio Note Kits. He brought both the L3 and phono stage preamps to the November meeting of the Audio Syndrome. Listening to a pair of Thiel speakers, I heard a comparison between a Rogue preamp and the L3. Based upon the relative differences between the two preamps, I asked my friend to bring the preamp to me for another listen.
I compared the L3 to my reference passive preamp. At that time, the L3 was not yet broken-in. My friend preferred the L3 to my passive preamp, and I was favorably inclined to consider a review. My friend left the L3 and after 50 hours of additional listening time, I told him to inform the distributor, Brian Smith, that I wanted to review the preamp.
Design Goals, Parts, and Assembly Instructions
The finished product Audio Note M3, is a transformer coupled line stage preamp which retails at a price exceeding $6000. It has been in production for more than 10 years. The L3 was designed to offer the circuitry and technology of the M3, using the M2 power supply, in kit form.
The standard version of the L3 has a retail price of $1699. Thus, as a DIY project, one approaches the sound of the M3 for less than one half the retail price.
The following is a list of the salient parts of the L3 preamp:
1) Audio Note-designed mains, choke, and output transformers.
2) Aluminum paper and oil capacitors manufactured by Jensen and Audio Note.
3) Audio Note stranded copper shielded cable
4) Panasonic electrolytic capacitors in power supply
5) Noble volume control
6) Beyschlag resistors
7) Tubes—5687 (2), 6X5, and ECL82
Signature models include tantalum resistors, Blackgate capacitors, and Audio Note copper foil capacitors.
Tools needed to complete the assembly include:
Phillips screwdriver, wire stripper, wire cutter, soldering iron, nut driver and volt meter.
Some soldering experience, patience, and an ability to follow instructions are required for a successful assembly. Audio Note can furnish solder instructions (DVD), and practice parts for those without solder experience.
There are a series of steps necessary to build the L3, as indicated below:
1) Attach power supply and line transformers to chassis.
2) Solder parts to circuit boards.
3) Test power supply using volt meter
4) Attach wires from transformers to circuit boards.
5) Attach RCA female connectors.
6) Attach selector switch with rod, requiring a solder connection.
7) Attach volume pot, and cooper wire from volume pot to main output connectors,
8) Place tubes in sockets and perform DC check for each tube.
My initial impression of the L3 preamp, using the tubes furnished with the preamp, reminded me of the McIntosh C220 preamp, which I had reviewed in May of 2007. The latter is adept at distinguishing differences between components and recordings.
I devised a simple test., which entailed varying digital hardware, interconnects, power cords and tubes.
I chose to study the effect of varying the above components upon the sound of solo guitar and harpsichord, as I believe it is easier to detect differences in frequency response and spectral balance when listening to simple, rather than complex material.
A recording for two guitars from the renaissance period, Lawes , “Suite for two Guitars”, features Julian Bream and John Williams, RCA 09026-61450-2 CD. As cables, digital sources and tubes were changed, their affect upon the timbre of the guitar was immediate and obvious. At times the spectral balance favored the guitar strings. There was a dip in the upper bass/lower midrange region and the wood body was de emphasized. As well, I also noticed a more realistic balance of wood body and strings—an even frequency response. At no time was their a peak in the lower frequencies.
I continued listening, this time the harpsichord was the subject of my interest. A recording of Scarlatti’s “Sonata #12, K 119”, performed by Sophie Yates, Chandos 0635, was my 2nd musical selection.
Here again, the changes in the above mentioned components had a significant affect upon the voicing of the harpsichord. I observed a highly focused attack of the strings and a slight softening of that attack as well. The balance of the strings relative to the wood body of the instrument varied as well. The results of listening to the harpsichord recording were consistent with those of the guitar recording. In both cases similar frequency response alterations were produced.
As a consequence of the results of a simple experiment, I am confident of the similarity between the McIntosh and Audio Note preamps, with regard to the attribute of transparency. I believe the difference between the two preamps is mainly in the area of focus. I believe the C220 has greater focus and clarity but to a degree which can create the impression that one is listening to a solid state preamp. I think the Audio Note has a very slight touch of the “sound of tubes”.
Following completion of the experiment, it was no longer necessary to vary any component. Thus, I settled on a digital source, the Consonance 2.0 SACD player, an output tube, a Tungsol 6FQ7, an interconnect between CD player and preamp, the Empirical Audio copper coax cable, and a power cord for the L3, namely the Ear to Ear Black power cord with Leviton connectors.
I selected the above combination based upon my opinion that taken as a whole, it had the least inaccurate treble response.
Female voice represents a barometer of midrange and upper midrange response. When a voice is close miked, sibilance can be a problem. An audiophile favorite, Holly Cole, DON’T SMOKE IN BED, “Que Sera, Sera”, Alert Z2 81020, can be a challenge for any stereo system. Holly Cole’s voice was indeed within close proximity of a microphone.
I was relieved not to experience an exaggerated, forward pronunciation of consonants. While sibilance was evident, it did not detract from the enjoyment of the music.
The last two recordings were selected to assess soundstage width and depth.
Ravel’s “Alborado del Gracioso”, is a lively tone poem with a Spanish flavor. In addition to the sheer musical enjoyment from the interpretation of Ernest Ansermet and L’Orchestre de la Suisse Romande, London 414046 CD, this recording gives the listener an opportunity to experience depth and width. Solos from the wind instruments, clarinet and bassoon were the means for assessing the extent to which a stereo system and other components can contribute to the perception of depth.
A brief clarinet solo and a bassoon solo, slightly longer in duration than the former, were noted. The clarinet was positioned somewhere in the back of the orchestra, while the bassoon, also positioned near the rear of the orchestra, provided ambient cues of a large hall. Although I searched the liner notes accompanying the CD, there was no indication of the recording venue, other than its date and country of origin.
Andy Narell’s 1985 recording, SLOW MOTION, “Natty Stick”, provides an ideal test of width and decay. Initially, a bell is struck . As it loses SPL, one is able to hear the decay for about 8 seconds, even as another instrument appears in the foreground—an indication of a very low noise floor. Shortly thereafter, a wood block is struck. It’s position was behind and at the left edge of the left speaker.
After listening to all of the musical selections, I obtained 2 pairs of 5687 tubes—Tungsol and GE, respectively, vintage 1960s. The tubes furnished with the L3 are Jan Philips 1980s. I was curious to hear what affect the NOS tubes would have upon the performance of the preamp.
Stash your cash. Differences were minor and may not justify the expense of acquisition, considering the return on your investment, namely, an insignificant , improvement in sound. It has been suggested that transformer-coupled line stages are less tube sensitive than those using capacitors.
The L3 is not your father’s preamp. The epithets, “classic” or “vintage”, do not apply. Rather, the term “modern tube sound” is applicable. It belongs to the set of preamps which have been designed to minimize coloration, have a high signal-to-noise ratio, maximize resolution and have a balanced frequency response.
As a reviewer, I appreciated the opportunity to hear differences between passive and active components. It helped to clarify my preferences when listening for enjoyment rather than to analyze and/or criticize.
There are many tube preamps which for which the term “modern tube sound” is appropriate. Obviously, all preamps so termed do not sound the same. They differ in the execution of the above-mentioned parameters.
The L3 is highly focused. It is not romantic, euphonic, rich or noticeably colored in any way. It distinguishes itself from its “peers” in that it is slightly less focused, not the least bit analytical , has a balanced frequency response, and strikes an effective balance between resolution and listenability.
Speakers: Magnepan 1.6
Amplifier: VTL Deluxe 120
Preamp(s): Bent TVC passive and Nobis Proteus
Digital Sources: Vincent CD S6, Consonance 2.0 SACD and Exemplar DAC
Interconnect(s): Ear to Ear, Cryoset, Empirical Audio
Speaker Cable: Ear to Ear
Power Cords: Ear to Ear, Clarity Audio, Distech, Sound String< Element Cable
Signature, PS Audio Lab cord
Active Accessories: PS Audio Power Plant, Chang ISO 64, PS Audio Ultimate Outlet,
PS Audio Noise Harvester, Blue Circle Sound Pillow, PS Audio
Juice Bar, Enacom AC conditioner
Passive Accessories: Sound Fusion Sound Boosters, Enacom speaker filters, Enacom
Interconnect filters, Ophiopogon, Z String Z sleeves
Manufactured by Audio Note Kits
tel 613 822 7188 or SKYPE audionotekits.
Source: Distributor loan