Description: Push-pull, tube stereo power amplifier. Tube complement: eight 6550/KT88s (output), six 6922s (input/voltage amp), and two 5687WBs (driver cathode followers). Power output: 110W continuous into 8, 4, and 2 ohms (20.4dBW), terminated with rated load, 20Hz–20kHz, with <1% THD, both channels driven. SMPTE intermodulation distortion: <1%, 20Hz–20kHz, at 110W output. Power bandwidth (110W output): 15Hz–90kHz (–0.5dB points). Frequency response: 5Hz–40kHz at 1W (–0.5dB points). Input sensitivity: 1.25V RMS balanced for 110W output. Input impedance:…
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Sidebar 2: Measurements
The measurements of the Sonic Frontiers Power 2 were made in the unbalanced configuration, with selected readings taken in the balanced mode. All measurements were taken with the amplifier configured for an 8 ohm output tap (see more on this at the end of this Sidebar).
Following its preconditioning test, the Sonic Frontiers Power 2 was typically hot for a tube amplifier. Its voltage gain into 8 ohms measured 28.5dB, balanced or unbalanced. The input impedance measured 101k ohms (190k ohms balanced). DC offset was negligible at 0.4mV in the left channel, 0…
Kalman Rubinson wrote about the Power 2 in March 1999 (Vol.22 No.3):
In comparison with the Simaudio Moon W-5, the Sonic Frontiers Power 2 seemed relatively mellow in the bass and softer in the treble, but with a glowing presence in the midrange that the Moon W-5 lacked. Those features were advantageously mated to the Genesis 500 speakers. The Power 2, however, lacked the sheer, gutsy power of the W-5 on the Apogee Duettas, and was somewhat generous in the midbass with the Coincident Troubadors.—Kalman Rubinson
It was 1988. What to do about digital?
Few high-end CD players were available. Few digital-to-analog processors were on the market, and almost all were pricey. Audiophiles desperate for better sound sometimes purchased modified players—kludges, I called them. But this wasn't an attractive choice, either—$200 machines turned into $1000 wonders with maybe $60 worth of parts and an hour's worth of labor.
Enter Antony Michaelson, of Musical Fidelity. He (along with Arcam and PS Audio) introduced one of the first affordable DACs—a digital-to-analog converter called the…
"Over the past 12 or 14 years, a large number of DACs were marketed," wrote Antony in his press handout. "Initially, some got excellent reviews, but none had a market life or more than six or eight months. With few exceptions, they all used DAC and filter topologies similar to those of the CD players they were purported to improve upon."
After the Digilog, Antony concentrated on CD players, and over the years his company has produced some of the best—culminating last year in the limited-edition Nu-Vista 3D, which our analog-retentive Mikey reviewed—and flipped over last October…
By all means, reread Fremer's review of the Nu-Vista 3D in last October's issue. Mikey preferred the sound of SACDs played on a Marantz SA-1 SACD player to the sound of CDs through the Nu-Vista 3D. But he found that the 3D did a better job than the Marantz with regular CDs.
Here's how the argument in favor of buying a CD player goes: There may not be much software yet, but more is coming soon. So why not buy an SACD player mainly for playing CDs and have the SACD capability?
Seems like a good argument. Is it?
No one disputes that SACD players do a more than adequate job…
Upsampling as realized in the Musical Fidelity also does something else, which regular oversampling doesn't: it adds eight bits of random dither to the 16-bit CD. This has the effect of better resolving the 16 bits of information that are actually on the CD.
"You also end up with a better signal-to-noise ratio," Antony stated. "The A324 has an A-weighted S/N ratio somewhere in the range of 112-116dB, whereas our older A3 CD player, still a fine machine, had an A-weighted S/N ratio of 105dB. We're talking about an additional 10dB." (footnote 1)
"And that could help explain why…
Take Naxos 8.554244, Telemann's Darmstadt Overtures, performed by the Cologne Chamber Orchestra conducted by Helmut Müller-Brühl. The recording is literally breathtaking—when I start any track, I can hear the musicians inhale in perfect unison. (I hear it even better with a single-ended triode amp, like my Sun Audio SV-2A3.) Compared to the Rega Jupiter used as a player, the Jupiter with the A24 gave me an even more spectacular sense of space.
Or consider Naxos 8.553330, Tchaikovsky's Piano Music, Vol.2, performed by Oxana Yablonskaya. Again, with the A324, the sense of space around the…
Sidebar: Contacts
Musical Fidelity Ltd., 15-17 Fulton Road, Wembley, Middlesex HA9 OTF, England, UK. Tel: (44) (0)181-900-2866. Web: www.musical-fidelity.co.uk. US distributor: Kevro International, Inc., 902 McKay Road, Pickering, Ontario, Canada L1W 3X8. Tel: (905) 428-2800. Fax: (905) 428-0004. Web: www.kevro.com.
Sidebar: Measurements from July 2002 (Vol.25 No.7)
Sam Tellig enthused about the Musical Fidelity A324 D/A processor (footnote 1) in his April 2002 column (Vol.25 No.4): "At $1195, it's an astonishing bargain that belongs in Class A of 'Recommended Components,' " he gushed, concluding that he "wouldn't drop money on a more costly digital processor without first hearing this one." I thought it worthwhile, therefore, to submit this upsampling processor—not "oversampling," as we termed it on our April cover, Musical Fidelity politely tells us—to Stereophile's usual measurement regime. (You…