PS Audio DirectStream DAC
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The PS Audio DirectStream DAC (Digital to Analog Converter) is a handwritten, discrete, perfection based digital to analog converter that uncovers all the missing information hiding in your digital audio media.
CDs, downloads, high-resolution PCM or DSD based media are expertly upsampled in the DirectStream to ten times the DSD rate and output as pure analog directly into your amplifier or preamplifier. DirectStream converts any digital input format, such as PCM or DSD to a pure DSD stream and outputs near-perfect analog directly to your power amplifier or preamplifier.
Whatever the format, whatever the sample rate, DirectStream is a pure DSD based solution that fulfills the promise of a high-resolution analog performance standard the originators of CDs promised over 30 years ago. Hear what’s been missing in your music for all these years. If you know the sound of music and instruments, and want to hear what’s been missing on your discs, then this DAC is right for you.
Pure DSD Done Right
DirectStream converts all digital inputs, including PCM, to pure 1-bit DSD, in an elegantly-simple path. In the process, the PCM feed becomes more linear, less edgy, and never-before-heard musical details are released from all digital audio recordings.
DirectStream utilizes 66-bit fixed-point FIR filters, eliminates headroom issues common to PCM, flattens noise response in the 20-100kHz region, uses coefficients optimized for best sound rather than faster processing speed and optimizes hardware-specific operations not possible in software.
Unlike other processors available today, DirectStream unifies all inputs (PCM or DSD) at 10 x DSD, then uses a true single-bit double-rate DSD core engine. True DSD core engines (compared to the standard multibit Sigma-Delta converters followed by random lower quality multibit converters) offer advantages in simplicity, linearity, and in analog-like overload characteristics that avoid PCM’s “hard clipping” potential and a PCM processor’s propensity to mask subtle detail
10X DSD rate
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. This means that perhaps for the first time, the DACS volume control has no degradation or data loss at any volume setting, eliminating the need for a preamplifier if the user wishes.
30 bit frames
The design utilizes a minimum width of 24 bits and achieves at least 144dB S/N in all of the upsampling filters. Use of full precision in the upsampling filters and significant number of “guard bits” in the IIR filters and the sigma-delta modulator help maintain PS Audio's goal of perfecting the audio output.
The DirectStream design opts for at least one extra top bit everywhere in the digital path, coupled with an extra 6 dB of head room in the analog path above and beyond the 6 dB of headroom that SACD needs. No PCM or DSD program material will ever have dynamic restriction from the DAC itself.
Transformer coupled output
The output of the DSD engine is fed directly into the output stage which is based on high speed video amplifiers, passive filtering, including a carefully crafted high bandwidth audio transformer at the output. Unlike conventional DACS that depend on active analog output circuitry and the problems associated with them, DirectStream is purely passive.
Because the output DSD stream is running at double DSD rate (5.6mHz) the ability of active analog electronics to handle these tremendously fast frequencies without adding any sonic artifacts is a serious challenge, one handled without incident when passive means are employed as found in DirectStream.
No off-the-shelf DAC IC’s
A key design feature that makes the DirectStream’s performance possible is the hand written code that makes it work. Seven years in design by PS Audio's lead designer, Ted Smith, every operation and process was written from scratch to make sure the best possible audio performance was achieved.
Instead of being based upon a packaged PCM-based DAC chip, with all of its inherent compromises and limitations, DirectStream utilizes an FPGA (Field-Programmable Gate Array). An FPGA is capable of dissipating large amounts of heat, enabling intensive levels of signal-processing that are impossible to achieve with an off-the-shelf chip.
Go Direct into your Amplifier or Preamplifier
DirectStream provides a volume control that is perfect and never loses any resolution at any setting. This, coupled with two choices of output level, permits DirectStream to be connected directly to either a power amplifier or preamplifier for best sonic advantage. PS Audio's typical recommendation is to take DirectStream directly into your power amplifier, thus avoiding any potential sonic degradation that might be caused from the extra circuitry and volume control within a preamplifier.
In some cases it is preferable to include a preamplifier in the signal path. DirectStream can then be adjusted to maintain a fixed level appropriate for the preamplifier’s input.
This touch screen option (available on the remote as well) allows users to select normal or inverted polarity for every input and for every performance.
Some CD players and sources themselves invert polarity so that a disc you believe is inverted actually is correct played on a specific device and incorrect on yet another. To fix this problem you can assign each input on the DirectStream to switch to the proper polarity when you activate that input. Touching this control is the same thing as reversing the loudspeaker connections of both loudspeakers (+ to -) at either the amplifier or speakers.
Inputs and Outputs
DirectStream has seven digital inputs which include: two I2S, one TOSLINK optical connector, one coaxial S/PDIF connector, one balanced XLR AES/EBU, one asynchronous USB input and one optional Network Streaming Bridge slot. DirectStream has both single ended coaxial and fully balanced XLR outputs.
Pure 100% single bit DSD based D to A Converter
Most of today’s sophisticated DACs are IC based instruments using off-the-shelf-chips that are Multi-bit Sigma Delta based designs. While these are relatively simple to design and produce, they don’t often give the best results sonically. Because they are one-chip systems compromises are made in their architecture that found in DirectStream’s custom based architecture. DirectStream takes both PCM and DSD, upsamples the data and converts to single-bit DSD and then outputs pure music regardless of input format for the data. The results of this design can be heard in increased musical information presented to the listener at every opportunity.
Purely passive output stage
Most modern DACs use some form of active tube or solid state output stage to amplify, filter and drive the DACs output. DirectStream takes a different approach: passive. In one of the simplest, elegant and musically correct executions of an output stage, high speed class A video amplifiers are used as the final switch for the single-bit, double DSD output of DirectStream; feeding a high performance passive audio output transformer. The transformer is specially designed to act as both the galvanic isolation between the DAC and the outside world as well as the primary low pass filter required to present a perfect, low distortion, low noise output signal. When you listen to DirectStream you never are accosted by added bright, hard glare in the music as happens with many active designs. Instead, clean, pure music flows from the DirectStream directly to your preamplifier or power amplifier.
Resolution perfect volume and balance controls
Designer Smith perfected a 100% bit-perfect volume and balance control that’s built into DirectStream, enabling users to control the output level when feeding directly into a power amplifier or preamplifier. That the volume control is completely bit-perfect means there is no loss of resolution for any volume setting, a feature unique amongst the majority of DACS in the world today. The ability to eliminate the preamplifier in the system without any resolution loss is a major benefit to DirectStream’s outstanding musical performance.
Simple, direct signal path with only one master clock
Typical high-end DAC designs use more than one master clock as you can see in the drawing we provided in the Overview page. There are often separate clocks for USB, Audio and others, causing major headaches for system designers trying to synchronize the clocks. DirectStream obviates the problem by basing the entire design on one master clock of extraordinary high quality. Used is a low phase noise, low jitter clock designed for DirectStream by Crystek. Using this advanced approach the need for synchronization is eliminated, jitter levels are reduced and music is delivered with a clarity rarely heard.
Immunity to jitter from sources
Sources have always had a major impact on sound quality with DACS. Transports, computers, CD players, cables all make a significant impact on performance into a typical DAC. This problem has been significantly reduced with DirectStream. Now, for perhaps the first time, sources of just about any quality and jitter level sound nearly identical. For example, you can take a cheap $30 DVD or CD player’s digital output, connect with DirectStream and have sound quality unthinkable for such a poor source. Performance levels no longer are dependent on the quality of source or connections; certainly not to the degree they have been in the past. Yes, cables and sources still make a difference, but with DirectStream that difference is reduced to nearly background noise. Whatever you use to play or stream your music now sounds as good as it gets.
Asynchronous high speed USB
DirectStream can match up to either a computer or a home network. If a network connection is desired, there’s is the optional Network Bridge available that slides right into the rear panel of DirectStream and adds an additional input. You can also connect directly to your computer via USB. USB communication, if handled properly, can have every sound quality advantage of a dedicated CD transport or Network Bridge. DirectStream provides a fully synchronous 24 bit 192kHz path for USB based audio. Using a good quality USB cable between DirectStream and your computer, like a quiet MAC Mini, provides an instant media server that can be controlled through any number of handheld devices like an iPod, iPhone or Android using a 3d party controller program. Your music can be managed by iTunes, Bit Perfect, Pure Music or Ammara for ease of use.
A handy feature on DirectStream is the polarity (phase) control. This touch screen option (available on the remote as well) allows users to select normal or inverted phase for every input and for every performance. Sources and music have no standard for absolute polarity, a fact easily demonstrated by switching polarities on the as the music plays. Many Audiophiles mark their discs in phase and out of phase and are very careful to select the proper phase before playing each disc. Some CD players and sources themselves invert phase so that a disc you believe is inverted actually is correct played on a specific device and incorrect on yet another. To fix this problem you can assign each input on DirectStream to switch to the proper polarity when you activate that input. Touching this control is the same thing as reversing the loudspeaker connections of both loudspeakers (+ to -) at either the amplifier or speakers. All live acoustic music is in absolute phase but some recordings may accidentally be made inverted and should sound more realistic and pleasant when you correct their phase with the switch.
Play directly into your power amplifier or preamplifier
DirectStream offers the ability to play directly into either your preamplifier or power amplifier through either its balanced or single ended outputs. You can select the optimum gain setting through DirectStream’s setup menu to match your amplifier and loudspeaker’s sensitivity. If you choose to go through a preamplifier, it’s easy to set DirectStream at maximum level (or any level you wish) to match the preamp’s gain. But should you choose to eliminate the extra electronics of the preamplifier, DirectStream is more than capable of driving the power amplifier directly. DirectStream’s unique zero-loss volume control maintains full resolution bit-perfect performance at any volume setting from the lowest to the highest levels.
Hear more than you ever imagined from CDs
DirectStream converts everything to DSD, even PCM before delivering the music to your system. This approach, coupled with careful design, low jitter and a simple and direct signal path has the benefit of uncovering details buried in the music you may not have realized are even there. CDs come alive with subtle details that were never apparent with your older DAC; details you never knew even existed. CDs sound more like high resolution audio than you ever imagined, closing the gap between higher resolution PCM and DSD copies. No longer do you need to consider replacing your current CD library because once you hear what’s truly on your discs, you may not need to consider upgrading to a higher resolution copy at all. Yes, it is that obvious and significant.
|Unit Weight||22 lbs [13.5 kg]|
|Unit Dimensions||14” x 17” x 4” [ 36cm x 43cm x 10cm]|
|Shipping Weight||31 lbs [19 kg]|
|Shipping Dimensions||20.5”x 24” x 10” [52cm x 61cm x 25cm]|
|Input Power||Model specific 100VAC, 120VAC, or 230VAC 50 or 60Hz|
Digtial audio inputs
|I2S(2), Coax, XLR Balanced, TOSLINK, USB, Network Bridge slot|
|I2S,S/PDIF, and USB -- 44.1kHz to 192kHz 16bit, 24bit, DSD 64, DSD 128
TOSLINK – 44.1kHz to 96kHz 16bit, 24bit
Analog Audio Output
|Connector||RCA/XLR Unbalanced /Balanced (X2)|
|Output level, low||1.41 Vrms(+5BV)/3.15|
|Output level high, maximum||2.81 Vrms (+8dBV)/5.3 Vrms (+12dBV)|
|Frequency Response||20-20KHz +/- 0.25dB|
|THD+N @ 1KHz (full scale)||<0.03%|
|Output Stage||Passive audio transformer, fed by high current, high speed analog amps producing double rate DSD.|
|Format||PCM or DSD|
|Sample rate (PCM)||44.1kHz, 48.0kHz, 88.2kHz, 96.0kHz, 176.4kHz, 192kHz|
|Word length (PCM)||16b, 18b, 20b, 24b|
|Data rate (DSD)||Standard (2.8MHz) or Double (5.6MHz) DoP on all inputs as well as raw DSD on I2S inputs|
|Input jitter reduction||effectively 100%, residual immeasurable. No input PLLs, FLLs.|
|Synchronous Upsampling, all inputs||28.224MHz|
|Digital Processing S/N ration||>146 dB|
|Digital Volume Control||Zero loss of precision|
|Analog Conversion method||Delta Sigma (DSD) Single-bit double rate|
I2S Digital Input
|Format||PCM or DSD. DoP on all inputs as well as raw DSD on I2S inputs|
USB Digital Input
|Connector||USB “B” Type|
|Format||PCM or DoP v1.1 (DSD over PCM)|