The Pace-Car is a very flexible architecture reclocker that can be used with USB, Wireless
audio servers, some PCI cards and even Transports. We like to call it the "Swiss Army
Knife" of reclockers. The Pace-Car reduces the jitter from these streaming audio devices
to inaudible levels.

The Pace-Car is available in two configurations, called "Types".

• Type One - for Wireless Music Servers, PCI cards or Transports that can accept a
  "Master Clock", "Word Clock" or "Bit-Clock" input
• Type Two - for USB systems or AirPort Express where the source clock is
  fixed or based on frequency synthesis or software generation

The Pace-Car PC board interfaces to I2S or S/PDIF-AES at the DAC and can have two
active outputs. I2S is preferred because it will have lower jitter, but the S/PDIF-AES
output is excellent as well. DAC's that have I2S inputs include:

1. Benchmark DAC-1 with Empirical I2S interface
2. Northstar 192
3. Northstar Extremo
4. Perpetual Technologies P-3A
5. Audio Logic
6. DEQX with Empirical I2S interface
7. April Music stello DA100 Signature

If you are driving one of these DAC's with I2S interface, the Pace-Car will come with
a compatible I2S cable.

You can also purchase the superior Revelation Audio Labs 'Prophecy' CryoSilver™
Reference i2s cable in reverse configuration for the Northstar DAC's from us
(not available from Revelation Audio Labs) for $369.

The standard Revelation Audio Labs 'Prophecy' CryoSilver™ Reference i2s cable will
work with the Benchmark DAC-1 with I2S interface mod. This is also available
from us for $369.

The Pace-Car can be configured to support one or two of the following sample-rates:

1. 16-bit or 24-bit/44.1 kHz
2. 24-bit/96 kHz
3. 24-bit/192 kHz

The Pace-Car uses a FIFO-memory (First-in, First-out) to temporarily store the audio
streaming data. The clock writing the data into the FIFO is independent from the
clock reading the data out of the FIFO. The output clock, which is the critical one can
be selected from:

1. Superclock4 - one or two
2. Low-jitter monolithic oscillator - one or two
3. Ultraclock - only one
4. External clock of your choice

The FIFO is split into two pieces, an input FIFO which is clocked by the incoming
stream and an output FIFO clocked by the outgoing bit clock. This way, the two FIFO's
are totally independent. There is no way for any jitter in the input FIFO to affect the
output FIFO. There are even separate power supplies for the input and output stages.

The input data stream is galvanically isolated (grounds are not connected) from the
output data stream, for I2S, S/PDIF-AES and Toslink inputs.

The sample-rate is automatically detected and the appropriate clock is routed to the
output FIFO. For instance changing from 16/44.1 to 24/96 is automatic.

Delivering a data stream to the Pace-Car that is an unsupported sample-rate results in
either a FIFO empty condition or a FIFO overrun condition. LEDs on the front panel
indicate these as well as any input sample-rate that is valid and detected.

Input data stream which can be:

1. Empirical I2S bus
2. S/PDIF coax or AES XLR
3. Toslink - replaces I2S

(All of these inputs are galvanically isolated from the ground in the output section.)

Two of these inputs can be selected by a front-panel toggle switch, for instance:

1. I2S or S/PDIF
2. I2S or AES
3. S/PDIF or Toslink
4. AES or Toslink
5. I2S and Toslink - requires special I2S connector and wiring at additional cost

Input DC power, which can be:

1. From the supplied 12VDC AC adapter
2. BPS or PBS battery supplies
3. Second 5V adapter included for use with USB converters

Output data stream which can be:

1. Empirical I2S bus
2. S/PDIF coax
3. AES XLR

Clock outputs which can be:

1. Master Clock 16-bit - 256fs
2. Master Clock 24-bit - 256fs
3. Bit Clock 16-bit - 64fs
4. Bit Clock 24-bit - 64fs
5. Word Clock 16-bit - fs
6. Word Clock 24-bit - fs

(all clock outputs are 50 ohm output impedance and 5V or 3.3V levels, factory selectable.)

The Pace-Car Type One reclocker is a true breakthrough in digital audio. This reclocker is
designed to work in concert with your wireless or networked music server. It is inserted
between the music server and your DAC. It drives a Master Clock back to the server
device, replacing the internal clock in the device, similar to Transports that have a
"Word Clock" input.

To add the Master Clock input to your wireless music server, a minimal mod must be
performed to remove the internal clock and replace it with a coaxial cable wired to a
coaxial connector.

Music Server Devices that are supported include:

1. Squeezebox
2. Sonos
3. Olive

As more become available, we will try to update the website ASAP.

The reviews of wireless audio servers, including Squeezebox, Sonos, Olive and others
all seem to conclude the same thing: that these devices are not quite up to the sound
quality achievable with high-end Transports.

Well, that is all about to change. The Pace-Car takes these devices to the next level by
reducing the jitter in the digital audio stream to inaudible levels. Those that claim their
upsampling DAC's and reclockers totally eliminate jitter are stretching the truth. Jitter
can never be totally eliminated, only reduced or minimized. The Pace-Car does not
eliminate jitter, but it does reduce jitter to inaudible levels.

Pace-Car Type Two

The Pace-Car type 2 reclocker controls the clock in the Pace-Car rather than the clock
in the source device like a type 1. Therefore, there are no mods to the source device
necessary. The Type 2 is appropriate for any source of which the clock cannot be
controlled. These include:

1. Computer direct S/PDIF or Toslink output
2. Off-Ramp, Freeway or other USB converter
3. AirPort Express

The way this works is the following: The clock in the Pace-Car is controlled to go
slightly faster and slightly slower than the incoming clock rate from the source. This
way, the FIFO never overflows or goes empty. The rate at which the clock changes
frequency is on the order of a few seconds. The change in frequency is extremely small,
and the rate of change is in seconds, so the DAC never even notices this and it is
completely inaudible. It is sort of like the frame-rate used for movies. The eye is
incapable of detecting any flicker because the rate is so fast. In this case, the change in
rate is so slow that the ear cannot detect anything.

Type 2 Pace-Cars can be used with virtually ANY source, but it must be specifically
tuned to that source. For instance, it can be used for USB converters such as Off-Ramp
and Freeway, but the particular Pace-Car must be tuned to that particular computer
that will be used to drive the USB to the Off-Ramp. Like wise, the PAce-Car must be
tuned to the AirPort Express, however in this case, since all AE's are the same, the
tuning should be the same for all AE's.

Multiple input configurations:
The Pace-Car can be configured for both Type 1 and Type 2 operation in the same device.
For instance, you can have a Squeezebox driving the S/PDIF input and an AirPort Express
driving the Toslink input. The front-panel selector switch can select between the two,
the Squeezebox operating in Type 1 mode and the AE operating in Type 2 mode.

Another configuration might be Northstar DAC driving the I2S input in Type 1 mode and
the AirPort Express driving the Toslink input in Type 2 mode.

The devices and mode types are as follows:

http://forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1204503359&openflup&9&4#9

"Highly recommended."(Sonos version)

Wappinghigh
March 2008

http://www.audiocircle.com/circles/index.php?topic=42526.30

"The Pace-Car is terrific, the best "transport" I've had.  I had high expectations
for this product, and my expectations were met and exceeded."

Capo
February 2008

http://www.audiocircle.com/circles/index.php?topic=47245.new#new

"Once I plugged it into my system (between the Airport Express and the
Scott Nixon TubeDac+) the sound improved greatly over what I was getting
out of the Sony DVP-S7000. The difference was day and night. Everything
sounded much more live, tighter bass, better imaging, faster attack. The
highs opened up dramatically. Wow. I’m very happy with my purchase!"

"Once I plugged in the Pace-Car in between Airport Express and DAC-1
things changed dramatically. Everything was much better, even the imaging
improved a bit - from “very respectable” to “very good.” Definitely, everything
sounds much better. It left the Sony DVP-S7000 and Airport Express
(without a Pace-Car) in the dust. Day and night difference. Yes, WOW!"

Arthur
November, 2007

The Squeezebox3 must be shipped to Empirical Audio, where we install an "SMA" type
coaxial connector in place of the far left connector on the backpanel. This connector
is used for Headphone Output or Remote IR Control in the stock Squeezebox3, so these
functions are eliminated. The new coaxial connector is used to input the Master Clock
from the Pace-Car.

The Squeezebox3 requires only the stock wall-wart and no further mods, because the
jitter in the data stream from the Squeezebox is totally irrelevant. It simply does not
matter. The quality of the S/PDIF cable used between the Squeezebox3 and the Pace-Car
also does not matter.

The Pace-Car must be powered-on and connected to the Squeezebox3 before powering-
on the Squeezebox. This is because the Pace-Car is now providing the Master Clock for
the Squeezebox3. After the Squeezebox is powered-on, it will function normally.

The output of the Pace-Car, either I2S, S/PDIF coax or AES then drives the DAC of your
choice. An I2S cable can be supplied if required.

The connected configuration is shown below with I2S output to a modified Benchmark
DAC-1:

Base price - $1100.00 plus shipping

Base package includes:

1. Pace-Car Type 1 with one monolithic oscillator (for 16/44.1)
2. 12VDC AC adapter
3. SMA clock cable
4. SB3 mods
5. I2S output

Options:

1. S/PDIF output - adds $100
2. AES output - adds $150
3. Additional monolithic oscillator (adds 24/96) - adds $40
4. One Superclock4 (for 16/44.1 or 24/96) - adds $300
5. Two Superclock4's (for 16/44.1 and 24/96) - adds $600
6. One Ultraclock (for 16/44.1 or 24/96) - adds $700
   (there is only room for one Ultraclock inside)

The Sonos can be used with a Type 1 Pace-Car to reduce jitter to inaudible levels.

The Sonos must be shipped to Empirical Audio, where we install an "SMA" type
coaxial connector for the Master Clock input. The Master Clock input connector
in installed in the location of the left channel input RCA, which is eliminated along
with the right channel input RCA connector as shown below:

The Sonos requires only the coaxial clock input no further mods, because the
jitter in the data stream from the Squeezebox is totally irrelevant. It simply does not
matter. The quality of the S/PDIF cable used between the Sonos and the Pace-Car
also does not matter.

The Pace-Car must be powered-on and connected to the Sonos before powering-
on the Sonos. This is because the Pace-Car is now providing the Master Clock for
the Sonos. After the Sonos is powered-on, it will function normally.

The output of the Pace-Car, either I2S, S/PDIF coax or AES then drives the DAC of
your choice. An I2S cable can be supplied if required.

The Sonos application currently supports only 16-bit/44.1kHz sample-rate, because
this is a limitation of the Sonos.

Base price - $1100.00 plus shipping

Base package includes:

1. Pace-Car Type 1 with one monolithic oscillator (for 16/44.1)
2. 12VDC AC adapter
3. SMA clock cable
4. Sonos mods
5. I2S output

Options:

1. S/PDIF output - adds $100
2. AES output - adds $150
3. One Superclock4 (for 16/44.1) - adds $300
4. One Ultraclock (for 16/44.1) - adds $700

Olive servers are also supported by the Pace-Car reclocker. The difference is that
the master clock is twice the frequency of the Sonos or Squezebox. This requires
also a special programming of the Pace-Car. The output quality at 16/44.1 is
identical to the Squeezebox or Sonos. A Master clock input connector (SMA) is
added near the S/PDIF output connector on the Olive and a clock cable is installed
internally.

Base price - $1350.00 plus shipping

Base package includes:

1. Pace-Car Type 1 with one monolithic oscillator (for 16/44.1)
2. 12VDC AC adapter
3. SMA clock cable
4. Olive mods
5. I2S output

Options:

1. S/PDIF output - adds $100
2. AES output - adds $150
3. One Superclock4 (for 16/44.1 ) - adds $300
4. One Ultraclock (for 16/44.1) - adds $700

The AirPort Express can be used with a Pace-Car type 2 to get extremely low jitter.

Mods to the AE are not necessary since the Pace-Car is a Type 2. The Pace-Car for
AE comes with a Toslink adapter for the AE so you can use ANY Toslink cable.
Because jitter on the incoming signal from the AE to the Pace-Car, you can even use
an inexpensive plastic Toslink cable.

However, because the AirPort Expresses do not all contain the same clock (from
different vendors), tuning must be done to the Pace-Car for the particular AE.
The customer has two choices:

1. Ship their AE to us so that it can be used to tune the Pace-Car and then be
   returned
2. We will purchase a new AirPort Express and use this one to tune the Pace-Car.
   The new AE will be included with the Pace-Car

The AE version Pace-Car only passes 16/44.1 data because of the AE limitation.

Because it is a Type 2, the Superclock4 is required. It cannot be used with the
standard oscillator or the Ultraclock.

Base price - $1400.00 plus shipping

Base package includes:

1. Pace-Car Type 2 with one Superclock4 (for 16/44.1)
2. 12VDC AC adapter
3. I2S output
4. Toslink adapter for AirPort Express

Options:

1. AirPort Express - adds $99 (if you dont want to send your AE to us)
2. S/PDIF output - adds $100
3. AES output - adds $150

The Northstar Transport has two features that make this application possible:

1. I2S output
2. Upsampling to 192kHz at I2S output

Similar to the Wireless Server applications, the Pace-Car drives a Master Clock back
to the transport using a coaxial cable, which replaces the clock internal to the Transport.

The Northstar Transport connects to the Pace-Car using it's I2S bus. Then the Pace-Car
output to the Northstar 192 or Northstar Extremo DAC is the I2S bus. The quality of the
I2S cable from the Transport to the Pace-Car is not a factor. The quality of the I2S
cable from the Pace-Car to the DAC is very important.

All streaming data is upsampled to 192kHz in the Northstar Transport, so this is the
only sample-rate needed for the Pace-Car. The front-panel indicators should always show
24/192.

Two Sources Supported
It is possible to have both a Wireless/Networked Server and the Northstar Transport
connected to the Pace-Car at the same time, with two separate Master Clocks, one driving
the Transport and one driving the Wireless Server. This version of the Pace-Car will have
a selector switch on the front panel to select between the S/PDIF input for a Squeezebox
(or other computer-server) and the I2S input for the Northstar Transport. Only two sample-
rates are supported, so they would be:

1. 16/44.1 and 24/192 or
2. 24/96 and 24/192

Base Price $1600.00 plus shipping

Includes:

1. Pace-Car Type 1 with one Superclock4 for 24/192
2. 12VDC AC adapter
3. 5VDC AC adapter
4. SMA clock cable
5. Transport mods
6. Superclock4 mods

Options:

1. Additional Superclock4 and selector switch for two sources (S/PDIF and I2S)
   - adds $450
2. S/PDIF output - adds $100
3. AES output - adds $150

Any Transport that has Word Clock, Bit Clock or Master Clock input can be supported by
the Type 1 Pace-Car. No mods to the Transport are required. A coaxial cable will typically
transmit the Word-Clock from the Pace-Car to the Transport.

The quality of the S/PDIF cable from the Transport to the Pace-Car is not important.

Base Price $1100.00 plus shipping

Includes:

1. Pace-Car Type 1 with one oscillator for 24/44.1
2. 12VDC AC adapter
3. SMA clock cable
4. S/PDIF input
5. I2S output

Options:

1. Superclock4 instead of Oscillator - adds $300
2. Additional Superclock4 for 24/96 - adds $300
3. S/PDIF output - adds $100
4. AES output - adds $150
5. Ultraclock in place of Oscillator (only room for one) - Adds $700
6. Each work-clock output - $250

This version Pace-Car can be used with Off-Ramp, Freeway, other converters, or
even with direct S/PDIF or Toslink output on a computer or laptop, avoiding the
converter altogether. Again, the incoming jitter to the Pace-car is unimportant.

This version of the Pace-Car is a Type 2, which "brackets" the output frequency of
the computer, so it must be tuned to the particular computer or laptop. Custom
tuning is necessary because the output frequency of computers varies so much.

Creating a wide enough frequency range to encompass ALL computers would
create a large frequency swing which can cause some DAC's to make noises when
the frequency changes. In order to prevent this, we make the Pace-Car Type 2
change frequency very little and very slowly.

To facilitate this, we require that the customer ship their computer or laptop to us
so that we can tune the Pace-Car to that particular computer. This Pace-Car Type 2
can then only be used with that particular laptop. It will probably not work with
other laptops, unless they are identical in type and year of purchase.

Currently, the USB Pace-Car is the only type that can support both 24/44.1 and 24/96
sample-rates.

Once the Pace-Car is tuned to the computer, there are a number of different devices
that can all be used with that computer and Pace-Car including:

1. Direct S/PDIF or Toslink output from the computer
2. USB to S/PDIF converter, such as Off-Ramp or Freeway
3. Wireless USB Hub and USB to S/PDIF converter
4. Opticis

Like all Pace-Car applications, once the data goes through the Pace-Car it all has the
same wonderful low-jitter quality.

Base Price $1650.00 plus shipping

Includes:

1. Pace-Car Type 2 with one Superclock4 for 24/44.1 or 24/96
2. 12VDC AC adapter
3. I2S input
4. I2S output

Options:

1. Second Superclock4 - Adds $650
2. S/PDIF output - adds $100
3. AES output - adds $150
4. S/PDIF input - adds $100
5. AES input - adds $150