Sound: woofer or dog?
The quality of the PW-1's bass response overall was excellent, its fairly uniform character blending fairly seamlessly with the Petites' own mid- and upper-bass response. The bass response of the entire system was now extended from its original lower limit of 60Hz to a solid 35Hz, with some reduced output at 32Hz. Overall, the frequency response was clean, uncolored, and smooth, with no peaks or…
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My room constraints discouraged further experimentation; the following comments should be considered in the context of what I was able to achieve in my difficult room.
The point is, even with an interconnect that cost as much as the PW-1 itself (MIT Shotgun), the bass performance did not significantly improve. I did notice, however, a slightly more relaxed quality to the Petites' high frequencies, presumably due to the A42's power supply being less stressed driving two speakers instead of four. The improvement was marginal, and the conclusion is this: If the amp is good enough, bi-amplification of the Trio system is a waste of money.
Conclusion, context, constraints, Chianti
Overall, I was quite impressed with the performance of the Trio system,…
Sidebar 1: Specifications
Magnepan Magneplanar MG1.6/QR: Two-way, floorstanding dipole loudspeaker. Drive-units: 2" by 48" Quasi-Ribbon tweeter, 442-in.2 planar-magnetic bass driver. Crossover: 600Hz, low-pass 12dB/octave, high-pass 6dB/octave. Frequency response: 40Hz-22kHz, ±3dB. Nominal impedance: 4 ohms (constant). Sensitivity: 86dB/2.8V/1m. Recommended power: 100W.
Dimensions: 64.5" H by 19.25" W by 2" D. Weight: 92 lbs/pair.
Finishes: Standard: white and black cloth, with oak, black, or cherry trim. Custom finishes available for an additional charge.
Serial numbers of…
Sidebar 2: Associated Components
Analog playback: VPI TNT Mk.IV turntable, JMW Memorial tonearm, Benz-Micro LO4 cartridge.Digital playback: Ultech UCD-100, CAL CL-15 CD players.Preamplifiers: Sonic Frontiers Phono 1 and Line 3, VAC CPA1 Mk.II.Power amplifiers: VTL Ichiban.Cables: MITerminator 2, 5; Kimber KCAG, KCTG; Bi-Focal XL; Synergistic Research Resolution and Designer's Reference; Nordost SPM.Accessories: Bright Star isolation systems, Tiptoes, Standesign, Bright Star, and Merrill equipment stands; PAC Super IDOS, MIT Z Center, and Nirvana AC conditioners; Synergistic Research A/C…
Sidebar 3: Measurements
The MG1.6/QR plays significantly quieter than the Thiel CS2.3 for the same voltage input. I estimated its B-weighted sensitivity at a low 83.7dB(B)/2.83V/m, though this will be moderated somewhat by its line-source behavior in-room. Its impedance (fig.1) is basically that of a 4.5 ohm resistor, modified by the crossover, which results in the peak at 600Hz. Any good 4-ohm-rated amplifier should be able to drive the Maggie without difficulty. There are no cabinet resonances—the MG1.6/QR doesn't have a cabinet.
Fig.1 Magnepan MG1.6/QR, electrical…
Lee de Forest filed for a US patent on his "Audion"—the first triode—on October 25, 1906, but never could explain why it worked (footnote 1). It was up to Armstrong and Langmuir, in their pioneering work, to place the hard-vacuum triode on firm scientific ground. When the US entered World War I in April 1917, the Army had to rely on French tubes. Six months later, Western Electric was mass-producing the VT-1 receiving tube and the VT-2 transmitting tube. However, it was only in the decade following World War I, as designers became conversant with the triode amplifier, that many of the…
Cary's 805 (at last)
With its ornate knobs and gold-on-black finish, the beautifully crafted Cary Audio Design 805 looks like a '30s period piece. A delightful feature is the "tuning eye" on the front panel. The eye, which monitors the AC output voltage, closes completely at the 50W output level. The open chassis is dominated by the large—almost 8" from head to toe—211 output tube. This true three-element tube has been heavily used over the years in RF amplifiers. The filament, a directly heated thoriated-tungsten type, requires a current of 3.25 amps at 10VAC. The 211's plate…
With its ornate knobs and gold-on-black finish, the beautifully crafted Cary Audio Design 805 looks like a '30s period piece. A delightful feature is the "tuning eye" on the front panel. The eye, which monitors the AC output voltage, closes completely at the 50W output level. The open chassis is dominated by the large—almost 8" from head to toe—211 output tube. This true three-element tube has been heavily used over the years in RF amplifiers. The filament, a directly heated thoriated-tungsten type, requires a current of 3.25 amps at 10VAC. The 211's plate…
The impedance magnitude should be fairly flat for efficient power delivery. The nominal impedance should be 8 ohms or higher, and ideally there should be no dips below 4 ohms—at least below 500Hz. Any tube amp is limited in its current delivery, and the lower the load impedance, the greater the current demand. As a simple example, compare two loudspeakers: one with an 8 ohm impedance vs one with a 4 ohm impedance. Assuming purely resistive loads, the current demand of the 4 ohm load is twice that of the 8 ohm load. I'm appalled at the recent trend toward vanishing-impedance loudspeakers. An…
Again, wonderful things were happening to human voice with the Cary. Rich and almost palpable, the individual voices of a chorus floated in space with remarkable resolution. The sensation of being able to pinpoint isolated singers in an ensemble was very believable. There was something about the 805 that made human voices sing more soulfully. The ability to convey human emotions transcended the realm of mere reproduction.
Even off the 4-ohm taps, the bass lacked impact and a convincing foundation. Taj Mahal's "John Henry's Fiddle" (string bass) on "Texas Woman Blues" (from Recycling the…
The Mozart and the 805 formed a synergistic duo. Objectively, the Mozart's upper registers are lively, with a notable metallic flavor characteristic of all the Scandinavian aluminum-dome tweeters I've heard. With the Classé M-700 solid-state monoblock, the metallic aroma had no place to hide. The 805, on the other hand, civilized the Vifa tweeter to the point of respectability. Again, I found 5dB of feedback to be an ideal balance between lushness and intimacy.
The Mozart simply brought out the 805's best, resulting in a fully 3-D illusion of space. Not only were instrumental outlines…