DirectStream DAC
Owner’s Reference
Owner’s Reference DirectStream DAC
Instructions for use
PerfectWave DirectStream DAC
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction i
Owner’s Reference DirectStream DAC
Important Safety
Read these instructions
Heed all warnings
Follow all instructions
Clean only with a dry cloth. For the Piano Finish Top refer to the instructions on page 8 of the Quick
Start Guide.
Do not place flammable material on top of or beneath the component.
All PS Audio components require adequate ventilation at all times during operation. Rack
mounting is acceptable where appropriate.
Do not remove or bypass the ground pin on the end of the AC cord unless absolutely
necessary to reduce hum from ground loops of connected equipment. This may cause RFI
(radio frequency interference) to be induced into your playback setup. Removing or bypassing
the ground pin on any electrical component is potentially dangerous and should be avoided for
safety reasons. A polarized plug has two blades, one wider than the other. A grounding type
plug has two blades and a third grounding prong. All PS products ship with a grounding type
plug. If the provided plug does not fit into your outlet, consult an electrician for replacement of
the obsolete outlet.
Protect the power cord from being walked on or pinched particularly at plugs, convenience
receptacles, and the point where they exit from the apparatus. Unplug this apparatus during
lightning storms or when unused for long periods of time.
When making connections to this or any other component, make sure all components are
off. Turn off all systems’ power before connecting the PS Audio component to any other
component. Make sure all cable terminations are of the highest quality.
Please contact your authorized dealer, distributor, or PS Audio if you have any questions not
addressed in this reference manual.
This product is manufactured in the United States of America. PS Audio® is a registered trademark of PS Audio International Inc., and is
restricted for use by PS Audio International, Inc., its subsidiaries, and authorized
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction ii
Owner’s Reference DirectStream DAC
The PS Audio PerfectWave™ DirectStream Digital to Analog Converter (DAC) is a stateof-the-art DAC, preamplifier and media center. DirectStream accepts PCM as well as
DSD Digital Audio data and converts it to high-performance analog audio that can be
fed directly to a power amplifier or preamplifier.
DirectStream represents a major advancement in the art of recreating the musical event.
Musical information that may have previously been hidden (or covered up by other
DACs) in digital audio media ranging from CDs to high resolution downloads will be
uncovered by DirectStream.
Subtle musical details and cues such as upper harmonics, decay, reverb and room
reflections will no longer be masked by the conversion process from digital to analog.
Your music will sound natural and you will be able to rediscover much of what you may
have been missing in your digital audio library with the introduction of DirectStream into
your system.
DirectStream features a unique architecture inside. From its digital inputs to its passive
output stage, DirectStream has been hand written, hand designed and personally
voiced by its principal designer, Ted Smith, along with PS Audio CEO Paul McGowan
and legendary loudspeaker designer and founder of Infinity Loudspeaker Systems,
Arnie Nudell.
DirectStream is based on a FPGA (Field Programmable Gate Array) as its core
processor and no off-the-shelf DAC chips are used in its design.
DirectStream is less sensitive to the vagaries of input source types and their level of
jitter than most DACs made. Remarkably low jitter sensitivity is one of the hallmarks of
this design and accomplished by not using classic edge transition detection techniques
used on the digital input data. Instead, a proprietary method of extremely fast sampleand-recognize technology is employed that reduces dependency on cables, jitter and
the quality of the incoming data source.
Once the data from the selected digital audio source has been input to DirectStream
it is upsampled to ten times the standard DSD rate of 2.8MHz before any processing
takes place. After processing by DirectStream all input data is converted to double
rate DSD (5.6MHz) and output through a passively filtered analog section consisting
primarily of a high-quality audio output transformer. Elimination of the classic active
analog output stage, with all its difficulties running at these high frequencies, have been
implemented with a high quality passive audio transformer.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction iii
Owner’s Reference DirectStream DAC
Why DSD?
DirectStream is entirely DSD based, even for PCM inputs. DSD was chosen as
the core engine for this instrument for a number of compelling reasons:
• DSD is simple to convert to analog: just low pass filter it.
• DSD is inherently linear: it’s hard to build a PCM DAC that always
takes the same sized step in the output for any possible unit increment
of the representative PCM voltage value. The best PCM technology
for linearity is arguably a resistor ladder, then all steps are at least
positive for a positive change in the input, but making resistors that are
accurate to one part in 216 is hard and to one part in 220 very hard. DSD
doesn’t need anywhere near this level of component matching.
• DSD soft clips when overdriven, more like magnetic tape: signals which
exceed the nominal full scale value only get slightly compressed if at
all. With PCM you either have flat tops which induce extra energy at
the squared off edges or, worse, you can have wrap around, which is
very audible.
• All bits in a DSD stream have the same weight: a single bit error
anywhere is barely measurable let alone audible. Some bits in PCM
carry a lot of weight and would make a very loud pop if changed. PCM
needs more error recovery to keep to a given signal to noise ratio (S/N)
with a slightly corrupted digital signal.
• Ironically, most sanely priced PCM players actually use DAC chips that
utilize a sigma-delta modulator (DSD) to get a DSD-ike signal anyway.
Similarly many (most) A/Ds are sigma-delta based. The typical PCM
path is analog -> DSD -> PCM -> disc -> PCM -> DSD -> analog.
The DSD path can skip the conversions to PCM. Those conversions
can’t be perfect and artifacts of the steep anti-aliasing filter or the
reconstruction filter aren’t considered benign by many.
• DiectStream handles the PCM conversion from AES/EBU, S/PDIF,
TOSLINK, I2S and USB without recovering a clock, by simply watching
for the edges and making decisions about what they mean in context.
The result is that any jitter present on the input is lost entirely in the
FPGA. There is no difference in TOSLINK or I2S because the output
clock’s rate only depends on the long term average rate of the inputs
not on any edge or other local feature.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction iv
Owner’s Reference DirectStream DAC
engine is it's
The heart of DirectStream is the DSD engine itself. Regardless of input format, whether
PCM or DSD, all data are upsampled to 30 bits running at 10 times the standard DSD
rate and then back down again to double rate DSD for noise shaping.
The internal volume control keeps complete precision: every bit in the input affects
the output of the DAC for any volume level. Except for the sigma-delta modulation
process itself there is no rounding, dither or other trimming, not to 24 bits, not to 32
bits, not to 48 bits, but rather a full 50. The incoming PCM signal is 30 bits from the
upsampling filter and the volume control is 20 bits wide so all 50 bits of the output are
used throughout the sigma-delta conversion, requiring more than 50 bits of precision.
DSD only requires a nominal 20 bit signal to noise ratio, this design utilizes a minimum
width of 24 bits with wide filter coefficients and 144dB S/N. Use of full precision
everywhere and many guard bits in the IIR filters and the sigma-delta modulator help
maintain our goal of perfecting the audio output.
Full headroom
with room to
While some designs may run out of headroom or approach saturation levels,
depending on the source material, the new design opts for an extra top bit everywhere
in the digital path coupled with an extra 6 dB of head room in the analog path beyond
the 6 dB of headroom that SACD uses. The top bit keeps PCM from saturating, even if
that PCM was not properly bandwidth limited in the initial recording process.
The output of the DSD engine is fed directly into the output stage, based on high
speed video amplifiers and a passive output transformer.
Most output schemes for DSD modulators are active low pass filters, covering
the required 120dB S/N ratio from 10Hz to 220MHz and have a number of design
challenges and problems associated with even the best designs.
If the analog processing isn’t linear and doesn’t have a very wide bandwidth it will
modulate the high frequency noise that’s inherent in DSD back into the audio band.
That modulation will not result in just low level noise. In practice it will be aliased
back into the audible band with serious sonic consequences. To maintain low noise
and linearity, the design incorporates both high speed symmetrical video amps and
a passive output filter. The first challenge in such a design is the output switch that
generates the final 1’s and 0’s of the modulator.
A very clean switch that hooks up the positive rail with a 1 and the negative rail with a
0 is essential. If it has too much resistance, if the resistance is different at the positive
end than the negative end, if the resistance changes from time to time, … the result will
not be as clean as it needs to be. For 120dB S/N the switch resistance has to be quite
consistent. Another design requirement is consistent and fast switching time.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction v
Owner’s Reference DirectStream DAC
If the switch is too slow it won’t keep up with the 5.6MHz signal used in this instrument.
If the switch doesn’t react in consistent times it will introduce jitter. Use of traditional
CMOS gates adds a lot of jitter as do cross-coupled totem-poled bipolar transistors.
Instead, DirectStream relies on high speed differential video amps, which are essentially
class A switches, have their outputs either near the top rail or near the bottom power
supply rail (without ever saturating) and provide a very clean DSD switch.
For the all important low pass filtering requirements an active filter adds self noise
even if it is effectively lowering incoming noise. A unique and effective solution to this
problem is a passive filter. The design uses a carefully crafted high bandwidth audio
transformer at the output of the instrument for both galvanic isolation from the outside
world as well as low pass filtering.
hardware and
design choices
The theory of operation, the firmware and the complex algorithms needed to execute a
design of this magnitude are daunting in their scale and scope. The actual hardware to
run the instrument is, perhaps, easier to grasp although no less critical to the perfected
Listed in this section are the highlights of the hardware, system’s overview and design
choices made to create an instrument of this caliber.
One master
1. Direct Stream runs from one master clock designed to
subtend all possible combinations of sub-clocks, from 44.1,
88.2, 48, 96, etc in order to eliminate the need for multiple
clocks that cause errors and problems associated when noise
from the unused clock propagates to the desired clock.
2. All sample rates supported are synchronously upsampled to
10x the standard DSD sample rate and then back down to
double rate DSD (2 * 64 * 44.1kHz). There’s no need for other
clocks to interpret the inputs, no matter what their sample
rate, because of the instrument’s single clock architecture.
3. The path from the single master clock to its retiming flip-flop
path is designed as short as possible and isolated from all
other clocking.
4. Connections between sections of the design have large
impedances, not only lots of power supply isolation, but also,
for example, 2k resistors in series with digital signals to slow
down the edges and lessen any noise transfer.
5. Similarly we run I C, SPI and other control signals as slowly as
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction vi
Owner’s Reference DirectStream DAC
they can possibly go without causing problems; we also
control their transition times, thus limiting the amount of
induced noise and jitter into the main digital processing
6. Outputs of the FPGA use the slowest, lowest drive
compatible with their function keeping noise as low as
7. We use slower, older technology CMOS when we
need CMOS. This choice lowers both noise and jitter
8. We use balanced signals when practical, they not only
lessen radiation and are less sensitive to radiation, but
they lessen noise in the ground and power rails.
9. We use non-saturation logic so the exact transitions
are more predictable. Coming out of saturation is a
statistical process.
10.High rate signals (or signals with fast edges) are isolated
from control signals and especially each other. If they
have to be fast they are terminated appropriately to help
in address jitter.
Jitter is
thoughout the
11.Jitter is addressed everywhere in the design. Every
component choice, every signal connection, every wire
routed on the boards are all hand done to lower noise
and pay attention to jitter.
12.0.1% precision thin film low temperature coefficient
resistors are incorporated everywhere in the audio
path. 2% film caps in critical places and 5% film caps
elsewhere in the audio path. By using 1/8W resistors or
1/4W resistors where others might use a 1/10W resistor
the temperature coefficient of the resistors are lowered.
For digital bypassing NP0/C0G or at worst X7R MLCCs
are used.
13.Low noise techniques are employed such as liberal
use of low inductance capacitor bypassing with a self
resonance frequency at the main clock rate to keep
noise from ever getting into the voltage rails in the first
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction vii
Owner’s Reference DirectStream DAC
Digital filtering
Double rate
14.Digital filtering in general, and the upsampling and noise
shaping filters in the sigma-delta modulators in particular,
offer many of degrees of freedom for a filter designer. There
isn’t a mathematically perfect filter to use (they all have
tradeoffs), so we’ve chosen the filters that sound best in our
experience and in addition to that we run everything with as
wide of an audio bandwidth as possible.
15.Although design choices might have been made to run
everything at single rate DSD (64 * 44100Hz), it was decided
instead to run at double rate DSD to have a wider audio
band below the upsampling and noise shaping filters. Noise
shaping is how a high rate sampled signal can have more
accuracy in part of the spectrum than the 6dB / bit rule and it
is understood that the quantizer in a sigma-delta modulator
can hide a multitude of sins in the noise shaping filter. Our
instrument still runs the noise shaping filter at full precision to
get the cleanest DSD signal possible.
16.No shortcuts are ever taken in the Digital Signal Processing
(DSP) section of the FPGA. Despite the fact that DSD is only
nominally 20bit S/N, the design uses a minimum width of 24
bits throughout the device. Where needed, very expensive
(in terms of math operations) filters with wide coefficients and
144dB S/N are employed along with many guard bits in the
IIR filters and the sigma-delta modulator.
17.Every trace on the PC board is hand routed: even for the
digital sections. No autorouting is employed so that each
trace, each critical path is calculated and designed for lowest
noise, jitter and isolation.
In conclusion
The PerfectWave DirectStream DAC represents a significant departure in the design and
execution of PS Audio’s products. We believe this new instrument will help further our
industry, music and the faithful reproduction of music around the world.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Introduction viii
Getting Started
Owner’s Reference DirectStream DAC
A good location for DirectStream is in a cabinet or on a shelf at an easily accessible
height. Care should be taken to keep it away from power amplifiers or large potentially
hum inducing products. The IR (infrared) receiver for the remote is located to the left
of the Touch Screen. A direct line of sight will will help with DirectStream's IR sensor,
which has been greatly improved from its predecessor, the PWD.
DirectStream and the PWT were designed to stack on top of each other if they are not
placed on separate shelves. To do this, remove the feet from the unit you wish to place
on top of the stack. Carefully place the top unit so it rests on the bottom unit. You will
note that the bottom of the corners of each PerfectWave piece is specially designed to
mate with the top corners of another PerfectWave.
Digital inputs
DirectStream offers multiple digital input choices including: The Network Bridge, XLR
(AES/EBU), RCA and TOSlink (S/PDIF), USB as well as I2S. All inputs, including USB,
are capable of accepting high-definition digital audio signals. The TOSlink input is
capable of 96kHz, 24 bit audio and all other inputs, including the USB, are capable of
handling up to 192kHz 24 bit of PCM or DoP data. The I2S inputs can handle single
and double rate DSD directly or DoP. Currently only the PS Audio NuWave Phono A/D
Converter is capable of sending pure DSD over I2S.
DirectStream uses an HDMI cable to transfer I2S data. This data can only be used with
another compatible component, such as the PerfectWave transport, and will not work in
other HDMI equipment as the I2S format incorporated does not comply with the HDMI
standards. The HDMI connector and cable were chosen to carry the I2S signal because
of their superior high-speed data transmission capabilities for multiple clocks and data
lines. PS Audio publishes its I2S standard and it has been adopted by multiple other
manufacturers as well.
DoP (DSD over PCM) is a standard allowing single rate DSD to travel over S/PDIF (the
RCA, XLR and Network Bridge digital inputs are S/PDIF compatible) as well as over
USB and I2S. It is not currently possible to send DSD directly over S/PDIF and the DSD
files must first be converted to DoP standards to travel this route.
It is possible to send DSD files (without conversion to DoP) over DirectStream's I2S
inputs as well as USB in the future. Most programs, such as JRiver Media Center and
Foobar 2000, will automatically convert DSD files to the DoP standards on the fly if the
appropriate checkbox has been enabled. There are no sonic penalties for conversion to
DoP as the raw DSD data is unaffected by the process.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Getting Started 1
Quick Start Guide
Owner’s Reference DirectStream DAC
Unpacking and
Register the Unit
PS Audio products come from the factory with a 3-year warranty. Please register your
new DirectStream. Registration takes just a few minutes, helps us inform you about
future upgrades, keeps track of your serial number and allows us to maintain the
highest standards of product quality of any company.
Carefully unpack the unit. Your new DirectStream comes wrapped in a soft organic
cotton bag to protect its beautiful finish. Use the included cotton gloves to remove the unit and place in the chosen location.
The piano black top cover has a protective plastic film. Remove this film.
Connect DirectStream to your digital sources using the appropriate connections.
Connect the AC cable into the receptacle in back and plug the unit into your Power Plant or into the wall.
To register your new unit, look on the back panel of DirectStream and note the serial
number. Using any web browser, go to and click on Register
Products. Once you have completed the registration process you can then go to
the PS website and look at the My Registered Products page. The link to this page
is located at the top right hand corner of the website once you are logged in. If you
do not have web access you may register the unit via mail or phone. Notification of
software upgrades to this product will be available only to registered owners via the
web and email.
There are four methods of connecting the digital inputs of DirectStream: Through the
home network, S/PDIF, USB and I2S. The home network option requires the addition of
the optional PS Audio Network Bridge be installed. S/PDIF is a serial digital interface
available as an optical source (TOSlink), coaxial source (RCA) or balanced source (AES/
EBU XLR). Connect to your digital sources with any of these three cable types.
USB is the preferred method of connection for a direct-to-computer connection and
DirectStream is capable of processing up to 192kHz 24 bit PCM data as well as both
single and double DSD converted to DoP. Connect DirectStream to your computer
using a well regarded USB cable and make sure to set the output of your computer
to the higher 192kHz 24 bit standard. Once connected, your computer should
automatically install DirectStream as a new device if you have a Mac. If you have a
Windows operating system you will need to download the appropriate driver from our
website and install it on your computer. The driver for DirectStream is the same as that
used with the PWD and NuWave DAC.
If the device is not recognized or you are unable to obtain output through DirectStream
it is possible there is a driver conflict on your computer. Please see the Troubleshooting
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Quick Start Guide 2
Quick Start Guide
Owner’s Reference DirectStream DAC
section for further assistance on playback issues via USB.
I2S input
I2S is available through several manufacturers as well PS Audio equipment such as the
PerfectWave Transport and the NuWave Phono A/D Converter. I2S is a parallel data
connection with separate clocks and data and transferred via an HDMI cable. I2S will
typically provide a slightly better performance standard than any serial data stream
such as S/PDIF or AES/EBU.
You can connect one or all seven inputs at the same time. For instance, you can
connect the USB input to your computer and the coax input to your CD player. Then
you can simply choose which one to listen to from the front panel touch screen (or the
remote) that selects the input. If you are using USB, make sure both the computer and
DirectStream are connected and powered up. USB also requires a driver to operate
properly. Mac computers running OSX have the driver built in. Windows based
computers require the PS Audio driver to be installed. Download the driver from our
website; it is the same driver used in the PWD. DirectStream will show up under Device
Manager as PS Audio PerfectWave DSD, under a heading PS Audio USB 2.0 Audio
Connecting the
DirectStream is designed to drive a power amplifier directly, or as another input on a
preamplifier. The outputs of DirectStream are high-performance, high current outputs
that can drive long lengths of interconnect cable without degradation.
Our recommendation is to use DirectStream directly into your power amplifier and
bypass the preamplifier. “There’s no preamplifier like no preamplifier”. Certainly this
is your choice but we believe the fewer pieces of equipment in the chain the better
performance of the system.
DirectStream has two types of analog outputs, balanced XLR or single ended RCA.
We do not recommend using both outputs at the same time. Be aware that most
amplifiers and preamplifiers will produce 6dB higher level with the balanced outputs
relative to the single ended outputs. If you are using both outputs be advised they will
be at different levels. Our preference for connection to a power amplifier or preamplifier
is through the balanced XLR outputs of DirectStream.
If there's a gain
If DirectStream has a gain mismatch with your power amplifier, you can use the
balanced outputs and achieve 6dB more gain or choose the single ended RCA outputs
for lower gain. DirectStream also has two output levels available to users. Go to the
setup menu on the front panel touch screen to select the best output level.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Quick Start Guide 3
Quick Start Guide
Owner’s Reference DirectStream DAC
RCA or single ended inputs will be the typical inputs as many preamplifiers, surround
processors receivers, integrated amplifiers and power amplifiers have only this standard
type of input.
Plug either the RCA or the XLR outputs of DirectStream into a line level input on the
preamp, integrated, amplifier or subwoofer. Do NOT plug the output of DirectStream
into a phono or equalized input of any type.
Once everything has been connected, use a high quality AC cable to power
DirectStream. DACs in particular are quite sensitive to AC power and produce a bit
of line noise themselves. Make sure you have a high quality shielded power cable to
power DirectStream, and a Power Plant if possible.
PS Audio produces an entire line of high quality shielded power cables that are
generally accepted as being some of the best in the industry. Whatever you choose,
make sure it honors the music.
Control and
Turn the AC power switch in the rear of DirectStream to the ON position. The power
switch is located just above the AC inlet.
As soon as the switch is activated the front panel touch screen will display the
initializing screen. This screen shows when DirectStream’s internal “engine” is being
loaded with the firmware that runs DirectStream.
After the initializing screen, you will see the main screen of DirectStream.
Front panel
standby button
The front panel PS logo button,
located on the upper left
hand corner of the unit, is the
Ready/Operation Mode control
for DirectStream. This control
has two modes: Ready Mode
and Operational Mode. Ready
Mode is designed to keep
power on to critical internal
circuitry including power
supply capacitors, thermally
sensitive semiconductors and
integrated circuits.
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Quick Start Guide 4
Quick Start Guide
Owner’s Reference DirectStream DAC
Press this front panel button to activate the Ready Mode or to place DirectStream in
Operational Mode. When pressed to activate the Ready Mode, the display as well as the
outputs are turned off, but all the unit’s critical internal circuitry remains active.
If you wish to conserve energy consumed by DirectStream it will be necessary to use
the rear panel power switch. Using this rear panel switch will remove power from critical
components and in order to gain maximum performance levels you will need to turn
DirectStream’s power on at least 3 hours before use.
Input selection
Should DirectStream need to be rebooted, use the rear panel power switch to power cycle
the instrument. It's best to wait 30
seconds before powering back on.
The first step is to select the input
you wish to play. The input select
is on the touch screen. Touch the
input selected which is the visible
input icon already selected. The
input selection list appears. Scroll
through the list and touch the
input you wish to play. The screen
reverts back to the main screen
and the selected input is displayed.
Each input has a lock light associated with it. The lock light has two states: connected
(green) and not connected (red). This lock light indicator is located in the upper right
hand corner of the input icon. Some transports will not appear connected until you
start to play the transport.
Input naming
For greater convenience it is
possible to assign a custom
name to each input such as
PerfectWave Transport, Apple
TV, etc. To name each input,
touch the input icon from the
main screen. The input list
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©2014 PS Audio Inc. All rights reserved.
Quick Start Guide 5
Quick Start Guide
Owner’s Reference DirectStream DAC
appears. Touch the small edit icon of the input you wish to name and the edit screen
appears. Type in the name of the product and touch “SUBMIT”. If you wish to return
to the default input name, go to the second keyboard screen (accessed by pressing the
numeric key labeled 123/.!) and touch “Restore Default”.
Filter and sample
rate selections
DirectStream upsamples every input and file type to 10X DSD rate before processing.
It is not possible to select the upsample rate for modification and therefore no sample
rate choices are available on DirectStream's touch screen.
Unlike many DACs, including DirectStream's predecessor, no filter options are available.
Adjusting the
output level
DirectStream has two output levels, High and Low. In the standard output mode,
DirectStream will provide adequate output level to directly feed a power amplifier
without use of a preamplifier. If the power amplifier, or preamplifier, is overly sensitive or
you need to reduce the output level of DirectStream for any reason, you can activate the
output attenuator to reach a lower level. There should be no sonic penalty for doing so.
To turn on/off the output
attenuator, press the filter
button on the remote. Or, go
to the setup screen which is
accessible by touching the
small tool icon at the top of
the default screen.
Screen brightness
The unit's screen brightness
can be adjusted in the setup
menu. The display can
be turned off by pressing
the button labeled “DIM”
located at bottom right of the
remote. When you are in the DIM mode, the screen will come back on when you touch
it or press a remote key. To turn the DIM feature off, press "ON." You can also adjust
brightness in the setup menu.
The Network
Bridge option
DirectStream can become far more than a high-performance stereo DAC. An optional
Network Bridge can be added that connects DirectStream to any home network. The
Bridge allows playback data from a source not directly connected to DirectStream using
a UPnP protocol and separately available controler and server, such as a NAS.
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Quick Start Guide 6
Quick Start Guide
Owner’s Reference DirectStream DAC
The Network Bridge incorporates the exact same Digital Lens™ technology found
in the PWT – without the input to the Lens being from a connected source. Instead,
the input to the internal Lens of the Bridge is over a network: addressable through an
Ethernet connection. Music stored on a hard drive or even an Internet radio service are
all accessible via this Network Bridge. Once installed, the Bridge will be accessed as
another input.
There will be no quality or performance issues on the Bridge for the same reason as the
PWT: the built in Digital Lens and output asynchronous clocks of both devices ensure
bit-perfect performance.
The Bridge slips right into the slot on the back of DirectStream and can be added in
less than 30 seconds by the owner. Simply remove the rear cover plate, insert the
Bridge and you are done. Complete instructions are available with purchase of the
Network Bridge.
The front panel touch screen software will be updated at the same time as the Bridge
installation allowing full access to music stored on your computer.
These units operate from sophisticated software that is built in to the device, but
upgradable by the user through the rear panel mounted SD card. To check for the
current firmware version simply touch the tool icon on the front panel, located in the
upper left hand corner of the touch screen.
Should firmware become available for upgrade, it can be installed through an SD
card placed in the rear of DirectStream. To install, place the SD card in the rear of
DirectStream, upside down. The SD card slot is found directly below the Network
Bridge slot. Then, follow these steps:
First, turn off the rear panel power switch. Wait for 10 seconds, then insert the SD card
(upside down with the gold connector pins facing up). Turn the rear panel main power
switch to the on position. The front panel Ready Light will begin blinking, signifying the
new firmware is being installed.
Care and cleaning
Once the blinking has finished, keep the power to the unit on until it has fully initialized
and is ready for operation again. Then remove the SD card.
DirectStream does need some care and is appreciative of being fed proper AC power.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Quick Start Guide 7
Quick Start Guide
Owner’s Reference DirectStream DAC
A Power Plant is recommended for this task.
Should minor scratches occur in your top cover, simply purchase any type of high
quality automotive scratch removal polish such as Kit’s Scratch Out or McGuire’s
products. Car finish polish and wax can both be used on this surface for a beautiful
The top cover is a piano black painted surface over HDF (wood).
The front panel touch screen can be cleaned with Windex or similar glass cleaners.
To clean, spray the cleaner on a soft lint free towel and carefully clean. Do not spray
cleaner directly on the unit.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Quick Start Guide 8
Quick Start Guide
Owner’s Reference DirectStream DAC
Remote Control
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Quick Start Guide 9
Owner’s Reference DirectStream DAC
USB not
USB – DirectStream not recognized, or no sound via USB
To play music from your computer into the DirectStream via USB you must have a driver
installed that communicates with the DirectStream. On a Mac computer with OSX or
Snow Leopard the drivers are already available and the unit should be automatically
recognized. You can then go and choose the PS Audio USB driver to play to by going
to System Preferences->Sound and select the PS Audio PerfectWave DSD. You can
also go to Applications->Utilities->Audio Midi and select the driver as well as set the
same rate.
On Windows the drivers are not yet available for automatic recognition. You will need to
download the PS Audio USB driver which can be downloaded from our website.
You can also contact our support staff via email or phone or simply go to and click on the Downloads page for the download. You must then
unzip the driver and install it on your Windows machine. Once installed, Windows will
recognize the DirectStream and allow you to select it for playback from any program on
your computer.
If you are unable to obtain sound via USB on a Windows based device it is most likely
the result of a partial or incorrect driver installation.
You may have also experienced a pop-up window asking you to provide the correct
driver. In any of these cases the remedy is quite simple. Remove the device and force
Windows to reinstall
the driver and the
DirectStream will
show up under device
manager as “PS
Audio PerfectWave
DSD” It should show
up under a heading
“PS Audio USB 2.0
Audio Devices”, this
is the USB2.0 driver.
The entry under
“Sound video and
game controllers” is
the USB1.0 fallback
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Troubleshooting 10
Owner’s Reference DirectStream DAC
Too much gain
DirectStream has enough output gain to directly drive most power amplifiers without a
preamplifier. DirectStream's volume control is a no-loss design and may be used at any
setting from 1 to 100 without fear of resolution loss.
However, if there is too much gain when you connect directly to a preamplifier or power
amplifier, it is possible to select a lower output gain setting. To do so, go to the setup
touch screen on DirectStream and choose the lower output option (see the Quick Start
guide). You can also turn the output attenuator on or off by pressing the Filter button on
DirectStream's remote control.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Troubleshooting 11
Owner’s Reference DirectStream DAC
Limited Three Year Warranty
Should I Register My Product?
• Registering your product validates the warranty start date.
• If you do not register your product within 30 days of service, a copy of your
purchase receipt from an authorized PS Audio dealer may be used as a proof of
purchase to establish the warranty start date.
• If no proof of purchase from an authorized PS Audio dealer or registration is
provided, the production date of the product will be used to determine the
warranty start date.
• Registration can be completed online, by phone, by mail, or by email.
• You may wish to sign up for PS Audio’s monthly newsletters, specials, product
updates, and/or Paul’s Daily Posts.
What Does this Warranty Cover?
This warranty covers defects in material and workmanship for products purchased from
PS Audio or its authorized dealers and agents.
What Will PS Audio Do to Correct the Problem?
In the event your product fails your sole remedy under this limited warranty shall be to
return the product to PS Audio or an authorized PS Audio repair center. The product
will be repaired without charge for parts or labor, replaced, or the purchase price
refunded through the original point of purchase, at the option of PS Audio.
What is the Period of Coverage?
This limited warranty is in effect for 3 years from the date the unit was first purchased
from PS Audio or its dealers and agents.
Who Pays for Shipping?
You are responsible to pay for the safe and proper shipment of the warrantied product
to PS Audio or its authorized repair center.
The PS Audio authorized repair center will pay the cost of returning the repaired or
replacement product to you under this warranty.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Warranty 12
Owner’s Reference DirectStream DAC
Not covered
What Does this Warranty Not Cover?
This warranty does not cover damage due to:
• Accidents, carelessness, improper transportation, misuse, neglect, or abuse
• Failure to follow the operating instructions that are provided by PS Audio in the
owner’s manuals (available for download at
• Use in any manner inconsistent with PS Audio’s operating instructions (available
for download at
• Lack of routine maintenance
• Connection to an improper voltage supply
• Alterations or modifications to the unit
• Improper or unauthorized repair, including repairs not authorized by PS Audio or
a PS Audio authorized repair center
• Fire, lightning, flood, “acts of God,” or other contingencies beyond the control of
PS Audio
• Products purchased through an unauthorized source (if you have questions as
to whether or not a dealer is authorized, please contact customer support at
• Products with a factory-applied serial number that has in any way been altered,
defaced, or removed
Limitations on PS Audio’s Obligations Under this Warranty
• In no event will PS Audio’s liability to you exceed the original purchase price of
the unit.
• This warranty does not cover the cost of custom installation, customer
instruction, setup adjustments, or signal reception problems.
• This warranty does not cover consequential and incidental damages. Some
states do not allow the exclusion or limitation of incidental or consequential
damages, so the above limitation or exclusion may not apply to you.
• In the event your warrantied product cannot be repaired, PS Audio will
replace or refund the unit. We reserve the right to replace any out-ofstock, discontinued, or limited edition products with a comparable product.
Discontinued products may not be available for warranty replacement.
Warranty transfer
How Can the Warranty be Transferred?
This warranty is for the benefit of the original purchaser of the product. The warranty
may be transferred to a subsequent purchaser during the 3 year warranty period. To do
this, you must contact PS Audio directly to set up transfer of registration.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Warranty 13
Owner’s Reference DirectStream DAC
If you require
service in North
How Do I Get Warranty Service?
To locate an authorized PS Audio repair center, for service assistance, or for help with
the operation of a product or just for information, please contact PS Audio customer
Warranty Service Within the US
Obtain an RA
Use original
State law
• You must first obtain a Return Merchandise Authorization Number (RMA#) to
receive warranty service and prior to returning any item. Contact PS Audio or an
authorized PS Audio repair center to receive an RMA#.
• You must put the RMA# on all returns. If it is not clearly marked, PS Audio will
return the package back to you, freight collect.
• You should include a description of the problem, along with the RMA# inside the
• Original packaging should be used for the safe transit of your PS Audio unit to
the repair center. If you do not have the original packing, PS Audio can sell and
ship to you replacement packaging.
• You are responsible for the cost of shipping the product to a PS Audio
authorized repair center. You should insure the product for its full retail cost
in the event it gets lost or damaged in transit. PS Audio is not responsible for
damage incurred in products sent to us.
• Shipping your product in non-PS Audio packaging may void this warranty. PS
Audio reserves the right to charge you for new factory packaging to return your
product after a repair.
How State Law Applies
This warranty gives you specific legal rights, and you may also have other rights which
vary from state to state.
If you are outside
the US
Warranty Service Outside of the US
PS Audio has authorized distribution in many countries of the world. In each country,
the authorized importing distributor has accepted the responsibility for warranty of
products sold by that distributor. Warranty service should be obtained where the
product was purchased.
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Service 14
Owner’s Reference DirectStream DAC
Changes to Our Products
PS Audio reserves the right to modify the design of any product without obligation
to purchasers of previously manufactured products and to change the prices or
specifications of any products without notice or obligation to any person.
Your serial
Your purchase
Date of purchase
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2014 PS Audio Inc. All rights reserved.
Service 15
Owner’s Reference DirectStream DAC
4826 Sterling Drive, Boulder, CO 80301
PH: 720.406.8946 [email protected]
©2012 PS Audio Inc. All rights reserved.
Notes 16
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