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Audible Illusions Modulus 3A preamplifier Page 6

Frontiers
Is the Modulus 3A the finest preamplifier in the world? I don't know. I can say this: when I raved about what I was hearing to Stereophile headquarters in Santa Fe, I was drop-shipped a Class A recommended preamplifier for comparison: the Sonic Frontiers SFL-2 line-stage and SFP-1 Signature phono-stage which are also based on 6DJ8 tube technology. Total cost: close to $5000.

The Sonic SFL-2 offers features the Modulus doesn't—balanced inputs and outputs, for example—and its performance and construction are clearly Class A, certainly in the same league as the Modulus,…

Audible Illusions Modulus 3A preamplifier Specifications

Sidebar 1: Specifications

Description: Phono section gain: 28dB at 1kHz (MM), 27dB (MC). Line section gain: 30dB. Output impedance: 1.2k ohms (main), 150 ohms (tape). Input impedance: 47k ohms. Frequency response: 2Hz-100kHz within 1dB, measured with a 1:1 probe/100k ohm load. Phono section RIAA error: 20Hz-20kHz ±0.25dB. Distortion: 0.02% (MC phono section); ±0.015% at 20kHz (MM phono section); ±0.15% at 1.5V RMS out, 20Hz-20kHz into 50k ohms, ±0.12% at 500mV RMS out, 20Hz-20kHz, into IHF load (high-level section). S/N ratio: 74dB ref. 5mV wideband input (MM phono section); 85dB ref. 1.…

Audible Illusions Modulus 3A preamplifier MF's System

Sidebar 2: MF's System

Analog: VPI TNT Mk.3 turntable; Graham 1.5t arm or Rockport Capella linear-tracking air-bearing arm; Clavis D.C. or AudioQuest Fe5 cartridges.
Digital: EAD T-7000 transport, EAD DSP9000 Mk.3 digital processor; Audio Alchemy DTI•Pro 32 digital interface.
Amplifiers: Cary Audio 805 single-ended triode or OCM 500 solid-state.
Loudspeakers: Audio Physic Virgo or ProAc Response 2.5.
Cables: XLO Signature 3.1 phono cable (JS is right on the money describing this); otherwise A.R.T. and Yamamura Systems Millennium 5000 interconnect and speaker cable throughout…

Audible Illusions Modulus 3A preamplifier Measurements

Sidebar 3: Measurements

Line-level measurements of the Audible Illusions were taken from the CD inputs to the main outputs; the phono measurements were taken at the tape outputs.

The Modulus 3's output impedance at its line output measured 1775 ohms (L) and 1802 ohms (R) with the level controls at maximum; lower settings of the main level control changed this measurement by only a few ohms. The input impedance at the CD input was just over 48k ohms and wasn't significantly affected by the main level control's setting. The output impedance at the tape output was 248 ohms…

Audible Illusions Modulus 3A preamplifier Measurements part 2

The change in THD+noise with output level using a 1kHz signal is shown in fig.4. Both the phono (top) and line-stage (bottom) performances are shown. The distortion and crosstalk measurements of figs.2 and 3 for the line-stage were taken at an input of 100mV, which results in a distortion just slightly above the minimum shown in this figure. The same measurements for the phono stage were taken at an input of 4mV, which resulted in an output very close to the minimum on the phono stage curve in fig.4 and minimized the effects of noise on the measurements.

Fig.4 Audible Illusions…

Audible Illusions Modulus 3A preamplifier Follow-Up, September 1996

Sidebar 4: Follow-Up from Stereophile September 1996, Vol.19 No.9

MF compares the Audio Research PH3 and Audible Illusions Modulus 3A

When you audition a component for the first time, usually what you hear are the gross differences between it and your reference. You may hear new things in favorite recordings, but such changes are meaningless. It's like cranking up the treble, hearing previously buried information, and calling it an improvement. Over time, however, I was able to develop a predictable "difference profile" between the two phono sections, which I would apply to…

Audible Illusions Modulus 3A preamplifier Follow-Up part 2

The Audible wins the battle in terms of high-frequency resolution, purity, and detail. Cymbal hits were rendered with somewhat greater delicacy, and reverberant trails seemed to go on forever and were convincingly focused in space. The PH-3 seemed more willing to let that go in favor of the lush midrange. But with its midrange energy and its superior bass dynamics and focus, the PH-3 wins the space race, projecting a more convincing three-dimensional, fully focused images front-to-back and side-to-side on the soundstage.

On Palace Music's Viva Last Blues (Palace/Drag City Records PR4/…

Fine Tunes #15

Pssst. Hey you. Yeah, you . . . we know you're a tweaker. It's nothing to be ashamed of. You just wanna make it better, right? Even as everyone around you wants to know when enough's enough already.

While I've gotten less tweaky in my reviews, I still hew to the tenets of resonance tuning. Given that tubes, capacitors, and even integrated circuits are microphonic, placement and support of audio gear is of paramount concern. I covered the basics of this two "Fine Tunes" ago, in July, but this month's column is for tweakers who'd like to understand more about the how and why of it.

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ProAc Response 2.5 loudspeaker

ProAc's designer Stuart Tyler sounded casual—almost bemused—when I spoke with him recently about the new 2.5, a floorstanding, two-way ported box in the middle price slot ($4500/pair) of his Response series. While answering my pressing queries about the crossover point, driver materials, cabinet construction, and other reviewer obsessions, his body language said, "Does any of that really matter with these speakers? You know what the real story is here."

Tyler's a successful veteran of this game. His designs are well accepted in both the audiophile and professional sound worlds (a major…

ProAc Response 2.5 loudspeaker Page 2

Did I need a meter to tell me I wuz getting bass? No! The 2.5 kicks sirloin. This is a speaker with serious visceral impact: tight, deep bass with a graceful, smooth transition into the midbass and above that keeps the 2.5 from sounding thick and heavy. There may be wool stuffed inside, but there's nothing "woolly" about the bass.

Nor is there a sense that you're getting the bottom octaves at the expense of midrange clarity, or that you're being tricked by a midbass bump. Nosiree: you put on a Joe Williams or Johnny Hartman album and you'll hear them with chests attached, but not…