Musical Fidelity A324 D/A processor Page 4

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 upsampling results in a perceived wider dynamic range?"

"Yes, that's part of it."

Other manufacturers use Crystal's upsampling chip too. It's not unique to Musical Fidelity. But some things are unique to the A324 and go a long way toward accounting for its exceptional sound.

Take the chokes, for instance. Antony claims that, to the best of his knowledge, the A324 is the only digital processor that uses power-supply chokes. The chokes are the same ones that Antony uses in his Nu-Vista M3 integrated amplifier, and they're far bigger than necessary.

"The larger chokes give the processor extra weight," Antony jokes, "and you know how audiophiles love heavy equipment. But the truth is, we'd already had these larger chokes made, for other products, and it would have cost us more to put in smaller power-supply chokes."

"You know what a choke is, don't you?" Antony inquired.

"Yes, but why not explain it for our readers?"

"Very well. A choke is an inductance coil, which is wound much like a transformer. It's a completely passive device, with four 6800µF capacitors. A choke cleans up the power supply—it literally chokes off power-supply noise, be it hum or whatever. A choke offers 0 ohms resistance to DC and very high resistance to AC—that is, signal. So when you get noise on the power supply, a choke acts to reject it."

"That's interesting, Antony. So perhaps there's less need for expensive power-conditioning equipment to clean up the AC mains coming in."

"Yes, there's much less need. Any noise that comes off the AC mains gets through the bridge rectifiers and creates a ripple at 120Hz, with associated high-frequency rubbish. With a choke, this noise is canceled."

"You've listened to the A324 with and without power-supply chokes. What are the sonic benefits?"

"A choke makes a difference at the margin," Antony said. "It's a question of how much space and air there is. Perhaps there's an additional level of refinement to the harmonic structure, but I'm not sure about that one."

Like most DACs and players, the A324, took some time to run in. But it was about three weeks before I heard what the A324 was capable of. If you get one, do have patience. What I heard during the first two weeks was that the DAC actually worked was impressive. But what I heard when the DAC was finally broken in was spectacular. This may not be the DAC to end all DACs, but for $1195, it probably comes very, very close.

My Rega Jupiter is an excellent CD player. It made a fine transport, too. But the A324, with upsampling, took performance to another level.

I heard more space and air, more low-level resolution, and, subjectively, wider dynamic range. The sound opened up and bloomed—almost the way it does with SACD. I heard harmonic delicacy—an extension and sweetness to the treble that reminded me of analog at its best, the way that SACD does.

I'll give you an example: Patricia Barber.

Ha! Fooldjus. (That's Fall Riverese for "I fooled youse guys." It's like "Toljus," for "I told youse guys.")

No, no Barber. I reached instead for a couple of trusty Naxos recordings. Six bucks a pop, on sale. Now if you can make a six-buck CD sound almost like a 20-buck SACD, that would be some trick, wouldn't it? That's exactly what the A324 did for me.

Musical Fidelity
US distributor: Kevro International
902 McKay Road
Pickering, Ontario, Canada L1W 3X8
(905) 428-2800