VAC 22.1 Owners manual

Model 22.1 HDCD® D/A Converter Instructions

The VAC 22.1 is one of the first D/A converters ever designed from the ground up around the Pacific
Microsonics PMD-100 HDCD® digital filter. This is one of the best digital filters in the world, and gives
superb sound with all CDs. The Model 22 was designed specifically around the PMD-100, an important
distinction from many other dacs where the PMD-100 was merely fitted to existing designs.

The jitter-resistant input is implemented with a Crystal Devices receiver. The D/A conversion IC is a high
quality Analogue Devices unit. The a-v conversion is accomplished by a unique "charge-pump" circuit that
results in low noise and distortion, with high transparency and ease.

The output stage is a highly accurate and linear Class A cathode-bias triode.

Six separate power supplies ensure pure operating conditions within the 22.1, helping eliminate the hardness
and opacity typical of lesser designs.

HDCD® and High Definition Compatible Digital® are registered trademarks of Pacific Microsonics, Inc.

General Directions

0.DANGEROUSLY HIGH VOLTAGES ARE PRESENT WITHIN THE 22.1 CHASSIS. IF YOU
NEED TO REMOVE THE COVER TO CHANGE THE TUBE, UNPLUG THE 22.1 FROM THE
AC POWER OUTLET AND FROM ALL OTHER COMPONENTS. ALLOW THE UNIT TO
REMAIN UNPLUGGED FOR THIRTY MINUTES BEFORE REMOVING THE COVER. DO
NOT RECONNECT THE 22.1 TO THE AC OUTLET OR ANY OTHER COMPONENTS UNTIL
THE COVER IS REPLACED AND SECURED.

TUBES BECOME HOT IN USE. DO NOT EXPOSE THE UNIT TO MOISTURE.

1.Complete all connections before connecting the AC cord to the wall outlet.

2.The associated preamplifier should be set to mute and/or its gain controls turned fully down.

3.The associated CD or DAT transport should be switched on and emitting a synch signal (playing).

4.The power switch has three positions: off, on but muted (indicator is red), on and unmuted (indicator
is green). The unit will automatically remain muted for 45 seconds after turn on.

5.Select a digital input (1 and 2 on coax, 3 for optional AT&T optical).

6.Continuous operation of the DAC is recommended for best sound and longest tube life.

7.The tube inside is type 12AX7/12AX7A/ECC83/E83CC. A low noise tube is not required.

8.Please call us with any questions you may have. It is better to ask than to guess.

Model 22.1 nominal specifications

Conventions Supported:

SP-DIF
AES-EBU professional

Sampling Rates:

32 kHz

44.1 kHz
48 kHz
...and all rates in between

Inputs:

2 coaxial, 1 optionally AES-EBU XLR jack
1 optical, AT&T type, optional (see special instructions)

Outputs:

1 set coaxial audio (unbalanced)

Output Voltage:

1.9 volts at full output

Distortion:

.02% at full output, 1 kHz
.02% at 9 below full output, 1 kHz

Tube Compliment:
1E83CC/ECC83/12AX7A (Golden Dragon preferred)

The VAC was voiced specifically with the Golden Dragon range of premium tubes. It is
recommended that this range be used when replacing tubes. Other brands will function but
likely will not sound as good.

AC Power Requirements:

120 VAC nominal, 50/60 Hz, 300 mA slow blow fuse. May be set for 240 VAC operation by means
of the voltage configuration card under the fuse holder, with 150 mA slow blow fuse.

Options:

BNC coaxial input connectors
XLR balanced input connector (AES-EBU)
AT&T optical input