PS Audio PerfectWave DirectStream DSD DAC
PS Audio PerfectWave DirectStream DAC Won 2015 Product of the Year Awards from Stereophile and The Absolute Sound: American-DAC Converts All Digital Music Files to 10x DSD
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After seven years of dedicated research and development, PS Audio's groundbreaking PerfectWave DirectStream DSD DAC uncovers everything previously hidden in your digital music files. This award-winning DAC up-converts all digital music files to 10x DSD, producing perfectly linear, edge-free sound guaranteed to reveal missing details in all of your music. Providing an entirely new approach to making music from any digital signal, the Colorado-made DirectStream DSD DAC will breathe new life into countless digital files and all high-resolution downloads. Whether it's MP3 or 24-bit/192kHz or DSD files, we guarantee that you have never heard your digital music sound this analog-like!
"This is a brilliant design, with exceptional execution, and paradigm-setting sound. I can tell you, this bloody DAC, DSD to the fore, is a real killer. Flat-out, stone-cold, and damn-straight."
– David Robinson, Positive Feedback
No off-the-shelf DACs inside this award-winner: DirectStream features hand-written, discrete, perfection-based digital-to-analog conversion technology that uncovers all the information hidden in your music and brings it to the forefront. CDs, downloads, high-resolution PCM or DSD based media are expertly up-sampled in the DirectStream DAC to ten times DSD rate and then output as the most pure analog signal through its singled-ended or balanced outputs into your preamplifier or use its preamp circuitry to output directly into your amplifier. However you use the DirectStream DAC, you will hear instruments and voices reproduced with an unheard level of realism!
"Whether you're a rabid DSD fan, or have strong convictions that PCM is the only way to go, PS Audio's goal for the DirectStream DAC was to make both types of recordings sound as good as possible. My personal take is that it substantially realizes that goal....It's easily the best DAC I've heard in my system, making digitally recorded music sound better than I've ever heard it."
– The Absolute Sound
DirectStream converts any digital input format, such as PCM or DSD to a pure DSD stream and outputs near-perfect analog signal. Whatever the format or sample rate, DirectStream is a pure DSD based solution that fulfills the promise of a high-resolution performance standard - one that was promised by the originators of the Compact Disc over 30 years ago. Hear what you've been been missing in your music for all these years!
"...I was already impressed by the DirectStream's ability to play music more compellingly than most D/A converters of my experience; here was the refinement that put its sonic presentation in the first rank, as well...Today, for those who've waited for a computer-friendly DAC that offers, with every type of music file, the best musicality of which DSD is capable, the PerfectWave DirectStream may be in a class by itself!"
– Art Dudley, Stereophile
- Pure 100% DSD based Digital-to-Analog Converter
- Resolution perfect volume and balance controls built in
- Up-samples PCM and DSD to 10x DSD rate
- Purely passive transformer coupled output
- Improves imaging and sound-stage
- Simple, direct signal path with one master clock
- Hand-written filters, processors and up-samplers
- Immune to incoming jitter problems from different sources
- Increased digital headroom
- No off-the-shelf IC DAC chips used
- Uncovers musical details masked by typical PCM based processors
- 7 digital inputs
- Fully balanced from input to output
- Color touch screen
Pure DSD Done Right
Introducing DirectStream, one of the most remarkable DACS ever built. Hand written, discrete, perfection based conversion that uncovers all the missing information hiding in your digital audio media for all these years. CD's, downloads, high-resolution PCM or DSD based media are expertly upsampled in the DirectStream to ten times DSD rate and output as pure analog directly into your amplifier or preamplifier.
Classic PCM based DACS, including many of today's DACS that can also process DSD, tend to cover up some of the subtle musical details buried deep within digital audio music; a problem inherent in their architecture. DirectStream solves this problem by employing a pure DSD single-bit approach for both PCM as well as DSD media.
This means that your entire library of music can finally reveal all the music and subtle low level details buried deep within its core. Imagine going to a recording studio and listening to a master tape of any recording made. This is the experience DirectStream provides its owners who enjoy a renewed sense of enjoyment and discovery when listening to everything in their library: CD's, downloads, DSD.
It is likely that whatever DAC you are currently using to decode your music may be covering up some of the finer details such as room reflections, upper harmonics, inner details and proper tonality. Removing the barriers inherent in PCM based processors can reveal more in your library than you might have thought possible.
Converting PCM to DSD can be an easy exercise using any number of computer software programs. Converting PCM to DSD properly, and in such a way as to reveal missing details in the music, is a serious technical challenge. To handle this properly 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 details.
The DirectStream DAC 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. In the DirectStream no limiting active output electronics are used thus making sure all details come through without any degradation.
DSD is inherently linear: it's nearly impossible to build a PCM DAC that always takes the same sized step in the output for any possible unit increment of the PCM value because of component matching challenges. DSD doesn't need this level of component matching and this means linear performance for all frequencies.
Like magnetic tape, DSD soft clips when overdriven: signals which exceed the nominal full scale value (by less than 3-4dB) only get slightly compressed if at all. With PCM the consequences are flat tops which induce extra energy at the squared off edges, or worse, wrap around which is very audible: the results can be an audible glare not present with DSD.
Ironically most reasonably priced PCM players actually use DAC chips that utilize a sigma-delta modulator to get a DSD-like signal anyway. Similarly most A/Ds are sigma-delta based. Matching the recording process to the playback process offers sonic advantages.
DirectStream handles the PCM conversion from all inputs 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 clocks is lost entirely in DirectStream. There is little audible difference between TOSLINK and, for example, I2S because the output clock's rate only depends on the long term average rate of the inputs. This means even poor quality sources sound musical.
Separating the digital and analog stages from each other, operating from a single master clock, 10x DSD processing and a purely passive output stage reveal musical details formerly buried within the digital audio media and masked by classic PCM processing and decoding techniques.
The DSD Engine
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. This critical step sets the DirectStream apart and is responsible for much of the uncovering of details in the music.
No rounding. 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 the goal of perfecting the audio output. Music has never been this clean and high-resolution analog-like.
Headroom. Depending on the source material some designs may run out of headroom or approach saturation levels. 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. This means 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. This approach is one of the critical success stories of DirectStream. 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.
Critical Design Choices
One master clock. Two clocks would mean more jitter. Even being able to shut one of them completely off while using the other adds stubs and possibly worse, logic or switches between the clocks and the final retiming-flip-flop. PCM architecture DACS almost universally require more than one clock and thus mask subtle details in the music.
10X sample rate. All input sample rates supported are synchronously upsampled to 10x the standard DSD sample rate and then back down to double rate DSD. There's no need for other clocks to interpret the inputs, regardless of their sample rate, because of the instrument's single clock input sampling architecture. This means music played through DirectStream is open and full of details formerly masked by other methods of decoding.
Low noise transfer. Connections between sections of the design have large impedances to slow down the edges and lessen any noise transfer, in addition to significant power supply isolation. This technique improves musicality and reduces, if not eliminates, the audible glare associated with traditional DACs.
Low interference. Control signals run as slowly as they can possibly go, plus control of their transition times limits the amount of induced noise (and hence possible jitter) into the main digital processing area. By slowing these control signals, music remains pure and unaffected by internal commands necessary for the DirectStream's operation.
Balanced architecture. Balanced signals are used throughout reducing radiation and noise in the ground and power rails. A balanced architecture is largely responsible for cleaning up the background and lowering noise floors to black levels.
Go Direct into Your Amp or Preamp
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. A 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.
One of the handiest features on the DirectStream that will see a great deal of use is the polarity (phase) control. 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. 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 polarity before playing each disc.
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. All live acoustic music is in absolute polarity but some recordings may accidentally be made inverted and should sound more realistic and pleasant when you correct their polarity with the switch.
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.