The digital powerhouse on the table: iFi Pro iDSD DAC
Author: Dong Hongjun Picture: Guo Zhenrong
Abstract: Headphone previously introduced the iFi flagship ear amplifier Pro iCan, which has various balanced and unbalanced terminals, powerful specifications, and is quite popular. The heart of a headphone gamer.
Headphone previously introduced iFi’s flagship ear amplifier Pro iCan. It has a wide range of balanced and unbalanced terminals and powerful specifications, which has won the hearts of headphone players. However, with such a powerful ear amplifier, how can it not be matched by a powerful DAC? Don’t worry, iFi has also launched a flagship DAC under the Pro series—Pro iDSD. It has rich functions, solid materials, and its playability is not inferior to the Pro iCan.
is not only USB, but also supports DLNA and Airplay.
Pro iDSD is not an ordinary DAC. When you take it out of the box, the various digital input terminals on the back panel can only be described as a dazzling array of things. It is amazing. In addition to the common USB Type B, S/PDIF coaxial, and AES/EBU balanced digital input terminals, it also has DLNA/UPnP network streaming playback functions, which can be supported by both wired and Wi-Fi. If you don’t want to buy a NAS, the Pro iCan also has USB Type A and Micro SD memory card (FAT32) sockets on the back panel. Just save files to a Micro SD memory card, USB flash drive or pen hard drive and install it on the Pro iDSD , you can play music after downloading a third-party DLNA playback APP from your mobile phone (the APP recommended by iFi in the manual is "Muzo Player").
iFi Pro iDSD can not only receive digital audio files from the computer through the USB Type B 3.0 terminal, but also supports DLNA, Airplay and other playback methods.
What if you don’t even have a USB flash drive or memory card at hand? It doesn't matter, Pro iDSD also has the more convenient Airplay wireless playback function. As long as you use an iPhone or iPad, and the Pro iDSD is connected to the Internet, you can directly play music from the iPhone or iPad.
8-channel DAC architecture, equipped with a variety of digital filtering and upconversion functions
is iFi's top-level digital source equipment. Pro iDSD does not just use one DAC chip. The USB receiving chip in Pro iDSD adopts the "xCORE-200" series chip launched by XMOS specifically for audio equipment, which can ensure that the digital audio is transmitted to the Pro iDSD digital circuit "without leakage or modification". The DAC circuit uses the DSD1793 chip produced by Burr-Brown, with two chips for each left and right channel. Through a special path setting, each channel has 8 channels to process dynamic signals.
In addition, the digital circuit of this machine also uses a Xilinx Spartan-6 FPGA chip. The original manufacturer stated in the official documentation that this FPGA chip controls the DSP function and complements the XMOS xCORE-200. It is equipped with "Crysopeia FPGA", in addition to providing five kinds of digital filter "Bitperfect", "Bitperfect+", "Gibbs Transient Optimisd", "Apodising", and "Transient Aligned", it also provides the "DSD Remaster" upconversion function, any audio can enter the Pro All can be upgraded to DSD512 or DSD1024 format.
Pro The USB receiving chip in the iDSD adopts the "xCORE-200" series chip launched by XMOS specifically for audio equipment. The left and right channels each use two DSD1793 produced by Burr-Brown, and the digital filtering is controlled through Xilinx Spartan-6 FPGA. with upscaling function.
According to the explanation in the manual, the "BitPerfect" mode does not use any digital filter, and the "BitPerfect+" mode does not use any digital filter, but the Sinc function is used as a correction for high-frequency roll-off. When the "DSD Remaster" function of these two digital filtering modes is turned off, the audio file will not undergo any upconversion processing and will retain the original sampling rate specifications. As for the three digital filters "Gibb Trasient Optimized", "Apodising" and "Transient Aligned", their filtering ranges increase from front to back (32 taps, 128 taps, 16,384 taps). When the "DSD Remaster" function is turned off Under normal circumstances, any audio file will be converted into a 705.6/768kHz PCM audio file and then digital-to-analog conversion will be performed.
As for the clock control circuit, which is extremely important in digital circuits, it inherits the circuit design from Hi-End sister brand’s flagship DAC AMR DP-777 DAC and uses iFi’s self-designed “Global Master Timing” femtosecond level clock control. wafer.Any digital signal input into the Pro iDSD will first be stored in the buffer memory and then, under the control of this "Global Master Timing" chip, sent to the XMOS xCORE-200 or FPGA chip for processing, so that jitter can be reduced to a minimum. . In addition, this chip can also be used as the main clock of the system, outputting a 10M or DARS clock signal through the BNC output terminal on the back panel. If you want a more accurate clock circuit, the BNC digital terminal on the Pro iDSD can also be set to external clock synchronization mode to receive clock signals such as atomic oscillator clock, 10M, and DARS.
transistors are combined to meet the needs of
Pro iDSD not only provides multiple digital input methods, but also provides multiple operating modes on the analog circuit. After the analog audio leaves the DAC circuit, it enters a third-order analog filter circuit made of discrete components to filter out the high-frequency noise output from the DAC circuit. In the front-end circuit, Pro iDSD adopts a pure analog sound control design and uses the famous Alps 100KBx6 six-track volume controller. Two of the circuits are responsible for the positive and negative signals of the left channel, and the other two circuits handle the right channel. The positive and negative signals allow Pro iDSD to deliver balanced, low-distortion sound performance at any volume. The analog input stage of the
machine is the same as the Pro iCan, and can be switched to transistor mode and vacuum tube mode. The transistor input stage circuit is equipped with J-FET transistors and operates in a pure Class A mode. The vacuum tube input stage circuit uses a General Electronics GE5670 vacuum tube on each of the left and right channels. If you want to have more control, Pro iDSD also has " Tube+" mode, by reducing the negative feedback mode, increases the sound coloration of the vacuum tube. If you are hesitant between crystals and tubes, don’t worry, Pro iDSD can still satisfy you at once! The input stage of the
analog circuit can be switched to three modes: "transistor", "Tube", and "Tube+". The "transistor" operates with a J-FET crystal, and "Tube" and "Tube+" operate through GE5670 vacuum tubes. operation. The
preamplifier, ear amplifier, and pure DAC can all be used. The
power stage also adopts a Class A operation method, using MOSFET crystals as buffers and bipolar transistors as power amplification. As for the analog output terminal, it includes a set of XLR balanced output and RCA unbalanced type, providing a total of four output modes: "Hi-Fi Var", "Hi-Fi Fixed", "Pro Var", and "Pro Fixed", of which " The difference between Var" and "Fixed" is that it outputs preamp signals and level signals. The XLR balanced output voltage of "Hi-Fi Fixed" is 4.6V, which is suitable for use with general audio equipment, while the XLR balanced output voltage of "Pro Fixed" The output voltage can be as high as 11.2V, which is suitable for use with professional equipment or Hi-End equipment that requires more thrust.
I bought a Pro iDSD. Do I need to buy an additional ear amplifier to make the headphones sound? The answer is no! iFi is showing off its Buddhist spirit here again. It has a 6.3mm single-ended ear amplifier terminal, a 3.5mm single-ended ear amplifier terminal and a 2.5mm balanced ear amplifier terminal on the Pro iDSD panel. In addition, the ear amplifier The output gain also has three-stage adjustment of "0dB, 9dB, 18dB" to adapt to headphones with different impedances and efficiencies. If your headphones are all in-canal headphones, or over-ear headphones that have no special requirements for thrust, I think the Pro iDSD alone is more than enough. Among the products in the same price range currently on the market, I would like to find a Pro iDSD that can be used as a USB DAC and a DLNA streaming player, with both crystal and vacuum tube drive methods, and a dual-channel/earphone It is really not easy to expand dual-purpose equipment.
Pro iDSD, like Pro iCan, uses iFi's special "iPower Plus" external power supply, and also has iFi's special capacitors inside for filtering.
The driving force of the ear amplifier is still good.
During the audition, I first connected the Sennheiser HD 800S to the Pro iDSD for listening. Although the Pro iDSD only has a 2.5mm terminal balanced output, and the 6.3mm and 3.5mm ear amplifier terminals are both single-ended terminals, it still shows satisfactory thrust when pushing high-end earmuff headphones.Listening with Sennheiser HD 800S, if the gain of iFi Pro iDSD is set to 0 dB, even if the volume is turned to the maximum, the volume still seems a bit weak. However, after adjusting the gain to 16dB, the volume has not been turned to 9 o'clock. direction, you can always feel the thick bass and powerful energy. However, after many attempts, I found that the sound of HD 800S when driven at 6 dB gain has both energy and softness. Driven in this gain and transistor output mode, Sennheiser HD 800S can drive a sound that is both musical and acoustic.
Playing Eva Cassidy's "Bridge Over Troubled Water" in "Live At Blues Alley" in transistor mode through Sennheiser HD 800S, you can feel that the iFi Pro iDSD has a neutral tone. In addition to Eva Cassidy's bright and high-pitched sound, The vocal lines and clear details of the lips and teeth, as well as the bright sound emitted when the cymbals are struck, have extremely high resolving power. The heavy drum rhythm in the music can also show the driving force of iFi Pro iDSD.
Listening in transistor mode is already so wonderful. If the drive mode is switched to "tube +", Sennheiser HD 800S will have another charming style. Different from the clean and crisp transistor mode, "tube +" allows Senheiser HD 800S to present another delicate tone like an oil painting. Like the faint guitar intro at the beginning of the music, it has been polished by vacuum tubes and become softer, just like mochi has been roasted, making it sweeter and softer. Similarly, Eva Cassidy's melody voice is more vivid than when driven by transistor. When she speaks and exhales, it is moister and hotter. At 4 minutes and 52 seconds, she sings "ease your mind" in falsetto. At this time, the subtle change of breath can move people's hearts even more. As for the drum rhythm interpreted by vacuum tubes, it not only retains the previous impact, but also has a thicker and more fleshy feel, making it more comfortable to listen to.
Pipe rhyme adds affection to details
Play "Krunk" by the violin and piano duo from the album "My Armenia", composed by Khacha Duliang, and you can also feel the clear and rich details of iFi Pro iDSD, while the timbre is smooth and warm feature. Promote the Sennheiser HD 800S in transistor mode and the volume at 11 o'clock. In the opening piano performance, you can feel the authoritative image of the bass keys, the fluctuation of the strings and the accompanying resonance of the piano body. You can immediately imagine the length of the grand piano. The subsequent high-pitched keys are soft and full of luster, pouring out of the headphones like ball balls. It is not difficult to imagine the pianist's left and right hands moving back and forth on the black and white keys, and his fingers flying on the keyboard. The image springs to mind.
The violin is an instrument that tests the reproduction ability of the DAC. Many DACs can easily present the ever-changing sound textures when the violin is played, but often fail to achieve the emotional and comfortable listening experience. However, through the iFi Pro iDSD in the vacuum tube mode Restored below, the bass strings have a thick, warm sound like a baritone singing, while the high-pitched strings have more condensed, smooth lines and noble colors, and the vibrato formed by finger shaking , as well as changes in the direction of movement. Through the excellent restoration ability of Sennheiser HD 800S, you can easily imagine it from slight changes in timbre.
While listening to this piece of music, I also tested the iFi Pro iDSD upscaling function. As the rising frequency increases, the original slightly soft image of pianos and violins becomes more condensed and clear, without causing a harsh or cold listening experience. It is as if glasses have been washed and wiped, and the edge clarity is greatly improved. In addition, upscaling can also enhance the perspective of the sound field. For example, the sound of violin and piano playing in the section is clearly separated from the sound of the players' clothes rubbing and breathing, making the music more distant. highlight.
is used in a two-channel system, which can better utilize the spatial and dynamic reproduction capabilities.
Since the Pro iDSD can adjust the output mode to be used with different systems, I adjusted it to "Hi-Fi (Fixed)" mode. Set to pure DAC use, connect to Linear Acoustic LAV60 II integrated amplifier via XLR signal cable to drive Dynaudio Contour 60.Play "Abendsonne" from Evelyn Huber's harp performance album "Inspire" in transistor mode. Through this system, the sound of metal wind chimes like elves flying, the endless rolling cello broken chords, the trickling harp strings, and the crisp and loud bamboo percussion instruments are heard in the vast area behind the speakers. It emerges like a mountain scene. In the clear air, you can clearly see insects and birds flying back and forth lively. Flowers, grass, leaves and trees are swaying in the wind, clean and vivid. It can be seen that Pro iDSD is played on a large two-channel system with a clean background, spacious audio and video, and a concrete and embossed shape. It is not incompetent because of its small size.
Finally, I played Valery Gergiev conducting the Kirov Orchestra in Stravinsky’s “Philips – 468 035-2” through the company’s two-channel reference system. "Girl's Sacrificial Dance". In fact, when I listened to the Brodmann F1 pair of speakers previously, I paired them with iFi’s flagship DAC and Linear Acoustic LAV50 II. At that time, the iFi Pro iDSD was able to present a wide and complete sense of space in this recording. I was impressed by the precise positioning of each part, the powerful timpani energy and the vivid rhythmic sensitivity. Listening to it this time through Dynaudio, not only are the aforementioned features fully present, but this time I use an XLR balanced cable to connect the source and amplifier. In addition, the thick sound of this pair of speakers gives this piece of music a solid foundation and stability. A sense of authority. Switching the iFi Pro iDSD to the "tube +" drive mode, this source does not create a "fake tube smell" with its pretentious fat body, blurred transient information, and unsubtle background noise. . On the contrary, the undulating energy dynamics, unstoppable force, clear and precise details and positioning, and the magnificent sound field effect are still retained in the listening experience. The difference from the crystal mode is that except for the texture of the sound becoming slightly In addition to the softness, the transient information generated when each sound is released, as well as the ending rhyme of the sound's disappearance, are all slightly longer, making the music sound more emotional. It can be seen from this that the vacuum tube circuit in iFi Pro iDSD is not just a useless function that is made casually to attract consumers, but a function that is produced with music as the main consideration and a well-thought-out design.
As for the impact of the digital filter and "DSD Remaster" function in Pro iDSD on the listening experience? I find that digital filters have the most significant impact on the transient details at the beginning of a sound, the "attack" part. Listen in "BitPerfect" mode, such as the labial breath at the beginning of each syllable when Eva Cassidy sings, the instant sound produced when the piano keys are touched in "My Armenia", and the sound produced by the drumsticks falling on the timpani in "The Rite of Spring" In this mode, the impact is presented most directly and vividly. As the tap number of the digital filter increases, the performance of these transient details becomes softer and smoother, and the details are still clear, but it sounds Less sharp, making the sound more natural. As for the "DSD Remaster" mode, it has a greater impact on the cohesion of the image and the cleanliness of the background. When the "DSD1024" setting is turned on, the edges of the body are the clearest and the background is the darkest, highlighting the sense of perspective and perspective in the music. Instrument image.
No wasted cost
I have used so many USB DAC and ear amplifier equipment, but there has never been one like this Pro iDSD, with rich functions, solid materials, and healthy sound. This suddenly reminded me of an article written by a person who worked as a product manager in a technology company on the PTT stock board. He said that when he chooses stocks, he uses the spirit of a product manager to carefully study the products launched by companies of the same type and find out the best specifications. If you choose a strong company and then buy their stocks, you can get a good rate of return. I think that although the Pro series launched by iFi is the flagship series, whether it is the Pro iDSD reviewed this time or the Pro iCan reviewed last time, its specifications are almost impossible to match with other products in the same price range. If Ifi has a listed stock, it is definitely a growth stock with unlimited potential.Of course, this is just a hypothesis, but what is certain is that the Pro iDSD has excellent specifications and every function makes the music feel better. Choosing it will satisfy you whether it is a headphone system or a two-channel system.
iFi Pro iDSD adopts a specially designed soft base at the bottom to prevent external vibration from affecting the internal circuit.
iFi Pro iDSD is the same as Pro iCan. The length of the screws runs through the front and rear of the machine, and it has a reinforced box structure. This is a design that has never been seen in other equipment.
Equipment specifications
iFi Pro iDSD
Type: USB DAC + network streaming player + ear amplifier
Support playback sampling rate: PCM up to 768kHz
DSD up to 49.152MHz (DSD 1024)
DXD and (2xDXD)
Input terminal: USB (required for DSD, DXD and sample rates above 192KHz)
AES3 (XLR – single link)
S/PDIF (coaxial/optical combo)
BNC multifunction (S/PDIF in or sync input)
Output terminal: Balanced XLR at 4.6V (+15.5dBu – HiFi) or 10V (+22dBu – Pro)
Single-Ended RCA at 2.3V (HiFi) or 5V (Pro)
Headphones 6.3mm SE 3.5mm Jack at 0.55V/2.1V/5V
Headphones BAL 2.5mm Jack at 1.13V/4.6V /10V
Headphones out 1,500mW RMS X 2 @ 64 ohm, 4,000mW max. 2 The 3mm ear amplifier output volume is in adjustment mode
Other functions: Play DSD and PCM audio files below 384KHz with various digital and analog filters
PMC Filters: Bitperfect 44.1 – 192kHz, always used for 352.8 – 768kHz
Bitperfect + 44.1 – 96kHz
Gibbs Transient Optimized 44.1 – 384kHz
Apodising 44.1 – 384kHz
Transient Aligned 44.1 – 384kHz
DSD Filters: 80KHz fixed third-order analog filter with correction for DSD's -6dB gain
Gain: 0dB, 9dB, 18dB three-stage adjustment.
dynamic range: 119dBA (solid-state, PCM, -60dBFS)
output power: (16Ω, balanced/single-ended): 4000mW /11,500mW
output voltage: (600Ω, balanced/single-ended): 11.2V / 5.6V
Input power supply voltage (Pro iDSD): DC 9V/6.7A – 18V/3.35A
Input power supply voltage (iPower+): AC 85 – 265V, 50/60Hz
Power consumption: 22W idle, 50W max.
Size: 213 (l ) x220 (w) x 63.3 (h) mm
Weight: 1980g
Price: 77,000
Import general agent: iFi audio Taiwan
Tel: 02-2370-2900
Website: ifi-audio.tw
