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The very nicely finished PSB Image B25 offered a voltage sensitivity slightly higher than average, at an estimated 88dB(B)/2.83V/m, which is within the margin of error of the specified figure. Its impedance was also moderately high, dropping below 6 ohms only in the lower midrange and mid-treble, with a minimum value of 3.7 ohms at 177Hz (fig.1). Good 4-ohm-rated amplifiers and receivers will have no problems driving this speaker.

Fig.1 PSB Image B25, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)

The wrinkle at…

But the pair of MC501s weren't all that McIntosh had sent along last fall. While perusing Mac's website last summer, I came across the C200, which had not been on active display at Home Entertainment 2003, where I had discovered the '501. Introduced…

Description: Solid-state, two-chassis, full-function, remote-control preamplifier with MM and MC phono stages, three balanced and eight unbalanced pairs of inputs, and three balanced and three unbalanced pairs of outputs. Frequency response: 10Hz-40kHz, +0/-0.5dB. THD: 0.002%, 20Hz-20kHz. S/N Ratio: 86dB phono, 100dB line (no weighting or reference level specified). Maximum output voltage: 12V RMS unbalanced, 25V RMS balanced. Output impedance: 50 ohms balanced, unbalanced. Input sensitivities: MM phono, 4.4mV for 2.5V rated output (1mV IHF); MC phono, 140µV…

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, Dynavector PHA-100 phono head amplifier.
Power amplifiers: McIntosh MC501 and Halcro dm58 monoblocks.
Loudspeakers: Focal-JMlab Nova Utopia Be.
Cables: Phono: Hovland Music Groove 2. Interconnect: Acoustic Zen Silver Reference, Nordost Valhalla, Siltech SQ-110 Classic. Speaker: Nordost Valhalla, Siltech LS-188 Classic. AC: Shunyata Anaconda Alpha…

Looking first at the C200's phono stage, this offered a respectable 40dB of gain set to MM and 63.3dB set to MC (assessed at the balanced tape output jacks). Despite this, the background noise level was low. The MM signal/noise ratio was 69.4dB unweighted (ref. 5mV input at 1kHz), while the MC figure was 56.4dB (ref. 500µV at 1kHz). A-weighted, these ratios improved to 83.4dB and 64.1dB, respectively.

The phono input offered very low distortion. Via the MM input, I measured just 0.0013% THD (true sum of the harmonics, ignoring the contribution of noise)…

I'm on the phone with AudioPrism's Victor Tiscareno. We're talking system basics.

"You know, Jonathan, before folks go out there and spend $3000 on a power cord, they could spend a whole lot less getting the basics right!"

He makes a good point. It's the right way to cover the bases without spending a fortune. The following DIY projects might cost some sweat equity, but they're low in cost, and offer high returns on investment. So let's don our toolbelts, and . . .

Live in a sweet old Victorian with spongy floors that flex…

Some fine tunes

Editor: This letter concerns Jonathan Scull's "Fine Tunes" in the February Stereophile, and his previous mentions of the use of damping materials to create a nonresonant listening environment.

I'm fully aware of the use of sand for this purpose, as 30 years ago, a sand-filled pedestal supporting my turntable completely eliminated some vicious low-frequency feedback that had been introduced by an 18" subwoofer. I thought the woofer was going to blow up, but the damping solved the problem.

Since I…

Some fine tunes

Editor: After reading Jonathan Scull's February 2000 "Fine Tunes," I decided to do something about the annoyingly springy suspended floor in my listening room.

I purchased two screw-type floor jacks from my local home center—total cost $30—and placed them under the floor in the crawl space. I put them at approximately one-third points along the length of the room and at the center of the joists. I tightened the jacks until they were snug, then added approximately one more turn.…

Run a set of interconnects from the EAD's analog outputs to an amplifier and you're rocking. Who needs a preamplifier, with its noise-inducing circuitry, and analog domain potentiometers? Anyone with other analog sources like tape decks, tuners or...turntables. That's who. That's me.…