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Product Review - Channel Islands Audio VDA-1 DAC - April, 2002

John E. Johnson, Jr.


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Specifications:

Inputs: Toslink Optical, Coaxial (RCA) SP/DIF

Locking Frequencies: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz

MFR: 20 Hz - 20 kHz

THD: 0.006% From 20 Hz to 20 kHz

Output Level: 2.4 Volts RMS; Two Coaxial RCA Output Jacks

Size: 2 2/3" H x 4 1/2" W x 4 1/2" D

Weight: 1 Pound

MSRP: $349 USA

 

Channel Islands Audio, http://www.ciaudio.com

Introduction

One of the things we get plenty of questions about are DACs that could be used to improve the sound of a mass market CD player. There are lots of DACs in the marketplace, but many of them are very expensive, being intended for the high-end user. Channel Islands Audio (CIAUDIO) has come to the rescue with their VDA-1, which is priced at pocket change. Dusty Vawter designed the VDA-1, and he was part of the Audio Alchemy (AA) team way back when. After AA went out of business, Dusty formed his own company and has been designing neat little products like the VDA-1 ever since, such as the VPC-1 Volume Control we reviewed recently.

The VDA-1 is for that old CD player that you just can't let yourself give away or put in the closet. DAC chips have progressed tremendously in the last 5 years, and so have the op-amps that take the low voltage from the DAC output, amplify it, and deliver it to the output jacks on the back of players and DACs. If you have an old player, and it has a Toslink optical or coaxial digital output jack on the rear panel, an outboard DAC with modern chips is just about guaranteed to improve the sound. This is where the VDA-1 comes in.

The Design

The VDA-1 uses a 96/24 Burr Brown PCM1716E DAC IC and Burr Brown DIR1701 Input Receiver. The analog output stage uses a Burr Brown OPA2132 dual op-amp. That is pretty much it. Power is supplied by a wall wart. You connect the digital output of your CD player (be sure to connect a 75 Ohm coaxial cable if you use the coaxial out) to the corresponding input on the VDA-1, and the coaxial outputs of the VDA-1 to your receiver or preamp. The VDA-1 stays on all the time (no on/off switch). If you have both the coaxial and Toslink inputs connected to something, and both sources are on at the same time, the VDA-1 defaults to the coaxial input.

When you turn your CD player back on, a blue LED on the front panel of the VDA-1 will glow to indicate that it has locked on to the digital output from your player.

On the Bench

I tested the VDA-1 with a Sony CA80ES CD player, BAT VK-5i preamplifier, BAT VK-75SE power amplifier, and Magnepan MG1.6/QR planar speakers. Cables were Nordost.

The reason I used the Sony CA80ES is that it is a few years old and has a mediocre performance compared to today's players. For example, here are two spectra that I generated using this player with a test signal CD. The first one is with a 1 kHz sine wave input.

Here is the 1 kHz spectrum using the VDA-1 with the Sony 80ES.

The comparison does not look good so far, does it? But wait. Here is a spectrum from the 80ES using two sine waves, one at 11 kHz and one at 12 kHz.

Now compare that with the same input signal, but using the VDA-1 DAC.

The reason that the calculated THD number for the VDA-1 is higher, is because of the peak at 60 Hz. This is the wall wart letting the 60 Hz AC get into the DC. It is not exactly a highly filtered power supply. (CIAUDIO offers a power supply upgrade for $179.) So, putting that number aside, look at the various harmonic peaks that the 80ES DAC creates vs. the peaks that the VDA-1 creates. You can see that the harmonics are much less in the 400 Hz to 20 kHz range with the VDA-1. I measured the harmonics all the way out to 90 kHz because, although the DAC and its filters limit their output to about 20 kHz, the op-amp receives the analog signal and can create harmonics way beyond 20 kHz. Notice that the VDA-1 spectrum is, for lack of a better description, simply a lot less messy in terms of all the extra peaks. Keep in mind that these are high signal levels from a CBS SMPTE standard test disc, and they really push the limits of everything. It is like the symphony is playing full blast. At more typical levels, most of these peaks would not be visible.

Frequency response of the VDA-1 was within 0.2 dB from 20 Hz to 20 kHz, as shown below.

The Sound

I compared the sound using CDs played in the Sony CE80ES, but also to the sound of SACD in a different player. SACD continues to amaze me, but that does not deal with the fact that we all have huge CD collections. The VDA-1 took the mediocre output of the 80ES and gave it more detail, more life. I noticed this particularly with the front edge of sharp signals, like harp. For example, in the new Berlioz Telarc release, the harp seemed very much alive with SACD, pretty much alive with the VDA-1, but pretty much dead with the 80ES by itself.

Full orchestral sections of the music also had more noticeable body to them, and less mush. One has to keep in mind that if just two input tones can create so many harmonics, the effects of a full orchestra can be devastating in terms of distortion that ruins the waveform. Violins seem to suffer the most, but it is noticeable with any instrument to varying degrees. Even bass instruments are affected, not in terms of the overall note they are playing, but the attack and that ever present rosin on the strings. It is these subtle things that bring the music to life in your home.

Conclusion

The CIAUDIO VDA-1 DAC is a very useful item for those old CD players that you refuse to put aside, and maybe the new player whose sound quality you are not quite satisfied with. It has nice performance and an even nicer price.

 

- John E. Johnson, Jr. -

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Copyright 2002 Secrets of Home Theater & High Fidelity
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