Analog source: SOTA Cosmos Series III turntable, Graham 2.2 tonearm, Dynavector XV-1S cartridge.
Digital source: Classé Omega SACD/CD player.
Preamplification: Manley Labs Steelhead phono stage, VTL TL-7.5 Reference line stage, McIntosh C200 preamplifier (as line stage).
Power amplifiers: Lamm ML1.2 Reference and McIntosh MC501 monoblocks.
Cables: Phono: Hovland Music Groove 2. Interconnect: Cardas Golden Reference, Nordost Valhalla, Acoustic Zen Silver Reference. Speaker: Cardas Golden Reference, Innersound. AC: Shunyata Anaconda Alpha &…
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Sidebar 2: Associated Equipment
Sidebar 3: Measurements
The Innersound Kaya was more sensitive than I was expecting, at an estimated 89dB/2.83V/m. However, this is way lower than the specified 98dB. Because the woofer and the electrostatic panel are driven by separate amplifiers, I have shown the impedance graphs for each separately. Fig.1 shows that of the panel. It is generally very high, staying above 50 ohms between 225Hz and 1950Hz. However, it plummets in the high treble, reaching a minimum value of 0.5 ohm at 29kHz, which is probably the series resistance of the speaker cable and the internal wiring. There is…
Paul Bolin wrote again about the Kaya in May 2005 (Vol.28 No.5):
Toward the end of my original audition of the Kaya, John Atkinson suggested that I experiment with the polarity of the speaker's electrostatic panel. Much to my surprise (as mentioned briefly in my December 2004 review of the Kaya), inverting the polarity of the panels of both left and right speakers had a drastic impact on the speaker's sound. With both woofers and panels connected in conventional polarity, the Kaya, at least in my room, had some problems in the upper bass/lower midrange. There had been a substantial…
"The realistic reproduction of orchestral music in an average room requires peak power capabilities of the order of 15 to 20W when the electro-acoustic transducer is a baffle-loaded moving-coil loudspeaker of normal efficiency."
—Peter Walker and D.T.N. Williamson, writing in the Journal of the Audio Engineering Society in 1954
According to evolutionist Richard Dawkins, the most important variable determining a person's religion is the accident of birth. Man of faith though I am, I agree—and I'll risk further sacrilege by suggesting that Dawkins' rule can be applied with equal…
And the metalwork is superb. Ken Kessler's luxuriant book Quad: The Closest Approach (footnote 2) mentions the "tropicalisation" of the original chassis—a delightful concept—and the new amp seems equally ready to withstand any climate. My first reaction on unboxing the Quads was to wonder, Where did they get that paint? It's exactly right. The 2005 Quad II has the same thick, wetly metallic shade of gray—with just the faintest touch of olive drab mixed in—as its predecessors, and I think that Quad made the right decision in not trying to ape the way older samples have darkened over the…
Sidebar 1: Specifications
Description: Tube monoblock power amplifier. Tube complement: two EF86, two KT66, one GZ34. Output power: 15W (11.8dBW into 8 ohms). Frequency response: 10Hz–20kHz, ±0.2dB. Input sensitivity: 570mV for rated power. Rated load impedance: 8 ohms. Damping factor: 11.75 at 700Hz, equivalent to a source impedance of 0.68 ohms into 8 ohms. THD: 0.08% at 12W/700Hz. Residual hum and noise: better than –90dB (no reference level quoted).
Dimensions: 12.25" (315mm) W by 6.5" (165mm) H by 4.75" (120mm) D. Weight: 18.25 lbs (8.3kg).
Serial numbers of units reviewed:…
Sidebar 2: Associated Equipment
Analog Sources: Linn LP12 turntable with Linn Lingo power supply, Linn Ekos tonearm, Linn Akiva & Miyabi 47 cartridges; Rega Planar 3 turntable, Lyra Helikon Mono cartridge.
Digital Source: Naim CD5x CD player.
Preamplification: Linn Linto phono preamplifier; Fi, Lamm LL2 Deluxe preamplifiers.
Power Amplifiers: Lamm ML2.1 monoblocks, EAR 890.
Loudspeakers: Quad ESL-989.
Cables: Interconnect: Audio Note AN-Vx, Nordost Valhalla, Linn. Speaker: Audio Note AN-SPx, Nordost Valhalla.
Accessories: Mana Reference Table, Reference Wall Shelf…
Sidebar 3: Measurements
It was difficult to resist nostalgia as I set one of the Quad II Classic monoblocks up on my test bench; the original Quad II, made by what was then called the Acoustical Manufacturing Company, was the amplifier to lust over when I first became aware of hi-fi in the early 1960s. But I am a trained professional—I can't let such feelings interfere with the task at hand.
The Quad II's voltage gain into 8 ohms was typical of modern designs, at 26.55dB. Its input impedance was not typical, however, at more than 1 megohm across the audioband. The amplifier…
A truly great preamplifier lets everything through, both music and distortion, but with such generosity that neither...is cramped and narrow.—Larry Archibald(footnote 1)
Finding a truly great, full-function preamplifier is a quest at which I have had only limited success. For a long time, I used an Audio Research SP-10 that I purchased back in the summer of 1984, but gave up on that fabulous device because, while its phono stage was (is) one of the greatest, it was too colored for CD use, and tube-replacement costs became unrealistic. The SP-10 gave way to a passive Mod Squad Line Drive…
Thick pcb traces carry the output signals to one pair of RCA jacks via an output muting relay controlled by a front-panel switch; the signal is also taken to the complementary FET buffers. Each pair of FETs is tied together face-to-face to give the best temperature and transfer-function tracking. Parts quality is high, with WIMA film capacitors and what appear to be expensive Holco resistors used in the FET buffer circuitry. Metal-film resistors are used in the balance, tape, and power-supply circuits.
The last, in fact, occupy the lion's share of the active pcb real estate. The…