Solid State Power Amp Reviews

Connecting the Hi-Cap to the system is far from intuitive. Instead of running a DC supply cable from the Hi-Cap to the preamp and an audio cable from the preamp to the power amplifier, the audio signal is first routed through the Hi-Cap before driving the power amplifier. Consequently, it is easy to hook up the system incorrectly, as I did initially. Note that only a single cable (either a four- or five-pin DIN connector) should be connected to the 62 preamp (besides the signal inputs). This unusual arrangement reportedly results in a superior grounding scheme (the Hi-Cap as central ground) which increases the system's sonic performance. If the 62 is used without the Hi-Cap, a DIN shorting plug must be inserted in the 62's five-pin audio output/DC input socket.

Again, careful attention has been paid to grounding, and the Hi-Cap's internal workmanship is excellent.

Listening
Minutes into the first listening session, it was apparent that the NAC 62, NAP 140, and Hi-Cap had some very special qualities. In fact, I was taken aback by the presentation. In some respects, this was among the best sound I have heard in my listening room.

First, the 62/140/Hi-Cap combination (hereafter referred to as the Naim system) had the ability to convey the music's essence in a way very few components can. The presentation was smooth, transparent, detailed, and involving. I had the impression that the electronics had disappeared from the playback chain, bringing me a step closer to the music. There was a certain ineffable quality about the music that was just right. The emotion and expression of the compositions and performers was heightened to the point that I wanted to hear more and more of my favorite music.

But what was it about the overall rendering that created such a powerful intimacy with the music? Let's come back to that question after first looking at specific aspects of the presentation.

Perhaps the most salient character of the Naim system was the completely natural portrayal of timbres and tonal shadings. There was a total absence of the grain, harshness, and stridency that often obscures an instrument's subtle harmonic richness. The treble, in particular, was sweet, soft, and warm, yet detailed and vibrant—often mutually exclusive qualities.

The Naim system's treble rendering was the antithesis of the hashy, metallic, electronic sound one sometimes hears from solid-state amplification. Cymbals retained their delicacy, conveying the impression of brass being struck. This was in sharp contrast to the sound of lesser components that seem to add a layer of white noise to the instrument. I find cymbals very revealing of a component's treble presentation; so often they take on a spitty, sizzly character that bears little relation to the actual instrument. Although rich in high-frequency energy, cymbals have a "gong-like" lower-frequency component that is quite fragile and easily obscured by a hashy treble. Such a presentation is fatiguing, annoying, and serves as a constant reminder that one is listening to reproduced music, rather than just music. I've gone into this discussion because I feel that the Naim 62/140/Hi-Cap are among a very select group of electronics that provide a completely natural rendering of cymbals and other HF-rich instruments.

In addition, treble textures were remarkably smooth and liquid, devoid of hardness or metallic edge. However, I wouldn't characterize the treble as laid-back or lacking in life. On the contrary, the presentation was big, open, and highly detailed—but in a subtle way. Moreover, the treble was infused with a wealth of inner detail one rarely hears from any electronics, regardless of price. Going back to cymbals, the relatively tiny sonic component produced by the initial attack of stick hitting brass was clearly audible through the Naim system (footnote 2). It's amazing how much inner musical detail emerges when not burdened by soundstage opacity or spectral contamination. This combination of liquid textures, harmonic rightness, and rich inner detailing contributed immensely to the Naim's overall sense of ease and musicality.

The mids were similarly smooth, but with a more laid-back quality. The harmonic structures of instruments and voices were remarkably lifelike and natural, creating a sense of realism. The Naim electronics resolved subtle tonal shadings without obscuring them with their own editorial statement. There was none of the common spectral signature superimposed on the music that often tends to diffuse the harmonic distinctions between instruments. Brass instruments—which are particularly sensitive to electronics-induced hardness—were round and liquid, with a palpable texture. There was no synthetic character or cold sterility.

I did feel, however, that a broad band of frequencies starting in the lower midrange and extending to the lower treble was slightly set back, giving many instruments a recessed or sometimes threadbare character. Although not unwelcome on all recordings, some music tended to lack "meat on the bone," as it were, with a loss of body. A good example of this is mounted toms in a drum kit. They lacked the resonant bite and dynamic attack that convey the energy of the instrument. On other instruments—saxophone, for example—I found this character euphonic. The tendency for recorded sax to have a bit of nasal forwardness was ameliorated by the Naim electronics, creating a smoother, more inviting presentation. On records in which the lead instruments are less than prominent, I had the urge to keep increasing the volume in an attempt to get more feeling of body. This, however, pushed the power amplifier beyond its capabilities.

This characteristic was more apparent with LP source. Looking back at Vol.12 No.2 (February 1989), in his review of the Audio Technica-Signet AT-OC9 cartridge TJN noted that "Its overall perspective is a bit laid-back." Perhaps the cartridge's "laid-back" character exacerbated the Naim's recessed midrange presentation, especially considering that the line stage exhibited less of this signature. I thus compared the Naim system with a Classé DR-5 preamp ($2500) driving VTL 225W monoblocks (footnote 3) through AudioQuest Lapis. Through the DR-5's phono section, I heard a greater sense of fullness and body through the midrange, but found the treble a bit hashy in comparison with the Naim. The DR-5/VTL presentation was more forward, livelier, and had a greater feeling of fully fleshed out textures.

After experimenting with the "S"-version phono boards (the standard moving-coil boards) and the "K" version (optimized for the Linn Karma and Troika), I decided to continue the auditioning with the "K" boards. The sound was more open, detailed, and vibrant, assuaging some—but not all—of my criticism of the phono section's feeling of a not completely fleshed out midrange. The "K" boards had better dynamics, especially in the bass. However, they did tend to exacerbate a slight trace of etch in the AT-OC9.

Replacing a pair of interconnects driving RCA-to-BNC adapters with a Naim-supplied phono cable fitted with BNC terminations further improved the sound from LP. Although readily available, RCA-to-BNC adapters should not be used. The degradations they introduce in the forms of veiling, loss of transparency, and imparting a slightly closed-in character, are greater than one would expect.

For further evidence that the AT-OC9 was not the hidden source of my phono-stage criticism, I auditioned the Naim system with a borrowed Benz Micro MC-3. The MC-3, besides being inherently better than the AT-OC9, was more suited to the Naim system. The mids were more fully fleshed out and the bass was fuller and more extended. I grew quite attached to the MC-3 during its all-too-brief visit to my listening room. This is a superb cartridge. The presentation still lacked visceral immediacy through the mids, however, and tended to be lean and lack LF weight.

After experimenting with the different phono cartridges, I drove the VTLs with the NAC 62 powered by the Hi-Cap. Although the NAP 140 and VTL 225W monoblocks shared many characteristics (textural liquidity, deep soundstage, smooth treble), the VTLs were clearly superior. Much of the missing weight and authority in the low end returned, providing a more satisfying musical foundation. Similarly, the laid-back mids acquired more body and presence, with a more palpable feeling. Dynamics were far better through the VTLs, sounding effortless and punchy.

Taking the next step, I replaced the NAC 62 with an Audio Research SP-11 Mk.II. Just as the VTL/140 comparison threw into sharp relief the 140's intrinsic character, so was the NAC 62's personality revealed when compared to the SP-11. There was another increase in LF weight and extension, greater midband presence and "meat," and heightened dynamic contrast. The 62 did, however, possess a similar ability to the SP-11 in throwing a deep and transparent soundstage, along with maintaining a sense of space around, and individuality of, disparate musical lines. The SP-11 also had a much more forward treble balance that imparted a greater sense of immediacy.

This experience of removing, one at a time, the Naim system's links from the chain (bypassing the phono stage with CD source, exchanging the 140 for the VTLs, replacing the 62 with the SP-11) led me to conclude that all the Naim circuits share a common character—lightweight balance, recessed mids, smooth treble—that is compounded by each stage through which the signal passes.

In light of the phono stage's—indeed, the entire system's—tendency toward leanness, careful cartridge selection is recommended. I should reiterate that these criticisms apply more to the phono stage: CD playback was less affected, and the slight feeling of added distance and reduction of midband energy tended to make digital playback more musical.

Despite the midband reticence, the feeling of instruments and voices existing in the listening room with some recordings was not subtle. Michael Newman's classical guitar on the Sheffield Lab LP (Lab 10) was remarkably lifelike. This recording, in my opinion, comes closer than any other to creating the illusion of a musical instrument existing between the loudspeakers (this record should be played back at a very low level). Although I had experienced this recording's palpability and realism through other components, the Naim system threw a startlingly convincing illusion of the guitar before me. Another example comes from Scott Kreitzer's tenor sax on the CD Kick'n Off (Cexton CR 11264). During a break in "Green Mountains," the unaccompanied sax took on a feeling of breathy, round richness and air that was quite convincing.

Adding to this impression of realism was the lush bloom surrounding instrumental outlines. Images were surrounded by an aura of air and space. My guitar and bass recording on the Stereophile Test CD was presented with the delicate recorded acoustic intact, softly enveloping the instruments.

In these areas—mid and treble textures, natural timbres, and bloom—the Naim 62/140/Hi-Cap perhaps come the closest to achieving tube performance of any solid-state system I've heard. My primary basis for comparison is the VTL 225W Deluxe monoblocks, amplifiers which do not impart a tubey artificiality to the presentation. Instead, they sound like neither tubes nor transistors—just music. In addition, the Naim system had many of the characteristics—smooth textures, a deep soundstage—of a power amplifier I reviewed recently: the Krell KSA-250. Although no challenger in the areas of low-frequency performance, dynamics, and ability to drive difficult loads, the Naim system achieved a level of musicality comparable in some aspects to the mighty KSA-250.

Another striking aspect of the Naim 62/140/Hi-Cap's presentation was the feeling of space, air, and depth. The system threw a huge, deep, and transparent soundstage before the listener that gave the music plenty of room to live and breathe. This sense of size, coupled with a remarkable transparency, created a feeling of envelopment and closeness. The music existed in space, unhampered by loudspeaker position or room boundaries. Soundstage width was impressive, with images and hall reverberation appearing beyond the loudspeakers. With my eyes closed, it was easy to be transported to various halls (or artificially created spaces). Moreover, the differences between each recordings' unique ambient character were clearly resolved. This highlights the Naim's remarkable ability to portray fine detail: nuances in ambience and space live within low-level information.

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Footnote 2: Perhaps I focus on cymbals because I'm familiar with how the instrument actually sounds, knowledge garnered during time spent being in a critical and analytical listening mode when recording drums and comparing the sound from the mikes to that of the live instruments.

Footnote 3: I just received a pair of VTL 225W Deluxe monoblocks with KT90 output tubes instead of EL34s, a new tube discussed by David Manley in this month's interview. Watch for a follow-up.