Arcam Delta 170 CD Transport
The Arcam Delta 170 is one of the first examples of an entirely new product category: CD transports. The concept of different CD transports having different sonic qualities is vexing. It is a simple matter to prove that the bit stream contains identical data from virtually any CD transport (see "Industry Update," Vol.12 No.8). According to Arcam, development of the Delta 170 was spurred by audible differences among transports heard by dealers, customers, and Arcam staff. The possibility that CD transports have their own sonic signatures is intriguing.
On the other hand, outboard D/A converters clearly make sense. CD-player (and DAT) owners can enjoy the improvements offered by the latest technology just by replacing (or upgrading) their D/A converters, provided their players have digital outputs. Digital output ports are becoming increasingly common: in early 1987, just 12 players had digital out, the number rising to 50 by early 1988. Today, the figure is over 100, with 29 also offering optical digital output (see Sidebar "Into the Optic").
The Delta 170 is based on a Philips single-beam mechanism. Unlike many other Philips-based players, Arcam has completely redesigned the machine, keeping only the basic laser assembly (CDM 1 Mk.2) and Philips data-recovery chips. The entire mechanical assembly is mounted on a vibration-isolated and damped subchassis. Compared with a Philips CD 880 transport, the Delta 170 appeared much more solid. For example, the metal supports that anchor the assembly to the chassis are larger and heavier. Arcam has put much thought and effort into this machine.
On the electronics side, the Delta 170 has some interesting design features. These include an optically isolated master clock and dual power supplies, each with its own transformer. One supply provides DC to the master oscillator and digital output stages, while the other serves the player servos and microprocessor. Digital output is in S/PDIF format from an RCA jack, or optical EIAJ (Toslink) connector.
Now comes the $64,000 question (or, more precisely, the $1295 question): does all this tweaking make it sound better? My philosophy in approaching this question is much like the American judicial system: CD transports sound the same until proven otherwise. Theoretically, they should sound the same. However, I would be the first to throw theory out the window if my ears told me otherwise. This is demonstrated by my experience with JVC's K-2 Interface, detailed in last month's "Industry Update."
First, I listened to the digital outputs of the Precision Audio DIVC-880 CD player and the Arcam Delta 170 decoded by the Musical Fidelity Digilog. I heard no difference either through speakers or the Stax headphones. Since Arcam's importer, Audio Influx, suggests that the audible benefits of their transport are more apparent through the Theta DSPre, I connected the digital outputs of both CD machines to the Theta's two digital inputs.
I listened analytically to a variety of music, both familiar and unfamiliar, audiophile and mediocre recordings. Still I heard no difference between the transports. Next, I put on my favorite music and forgot about critical listening; I just sat back and gauged the emotional impact of what I was hearing. As much as I wanted to hear audible differences, I could detect none. However, I should add that this experience is limited to one individual, under one set of circumstances, with essentially one playback system. I am interested in hearing from readers who have had experience with different CD transports.
Do optical cables sound different from coaxial cables? Yes. The difference is subtle, but nevertheless there. Bass seemed warmer and rounder. This phenomenon is surprising: how can changing a cable carrying ones and zeros make bass warmer? I never would have believed it possible without hearing it myself under test conditions totally under my control. There is much we don't know about digital audio that should be explored by critical listening, not blind acceptance of textbook theory. I have little doubt that our ideas about digital audio will be very different in ten years, provided we have the intellectual courage to accept new ways of thinking and challenge the status quo.
I find it hard to recommend the Arcam Delta 170 on the basis of sonics since I heard no difference between it and the stock transport. It is, however, very well made, ergonomically satisfying, and has many useful features. I strongly urge you to listen to it yourself and form your own impression. Again, my experience is by no means the final word on the matter.