In recent years, iFi Audio has delighted audiophiles by expanding its range of high quality DACs at a lower price than usual for this type of product. The brand is now back with a strong new product, the iDSD Pro. It is a Quad DAC with incredible performances, thought for an extraordinary restitution.

Quad DAC Stage

The iDSD Pro is based on 4 DAC Bit Perfect and supports Burr Brown's DSD, adopting a custom design. This configuration allows 4 pairs of signals to be used for an impressive hearing experience. Since digital processing is Bit Perfect, the device does not use ASRC (asynchronous sample rate converter) or oversampling except by selecting digital filters. Many filters are also available to adapt to listening:

• BitPerfect : No digital filter, minimum analog filter.
  Sampling rate: from 44.1kHz to 192kHz, always used for rates from 352.8kHz to 768kHz.
• BitPerfect + : No digital filter, analog filter corrects stop AF.
  Sampling rate: from 44.1kHz to 96kHz.
• Minimum phase : The filter has no pre-ring and minimizes post-ring.
  Sampling rate : de 44.1kHz à 384kHz. 32 Tap.
• Apodising : The filter has no pre-ring and moderate post-ring.
  Sampling rate : de 44.1kHz à 384kHz. 128 Tap.
• Transient Aligned : The filter has a pre-ringtone and an extreme post-ringtone.
  Sampling rate : de 44.1kHz à 384kHz. 16384 Tap.

An entrance section thought through down to the last detail

The iDSD Pro has a complete and truly high-end input connectivity. There is thus a USB-A 2.0 connector but also a USB-B 3.0 port, each being self-powered. There is also coaxial, 3-pole XLR and a Micro SD port. In addition, each input is galvanically isolated to significantly reduce interference. As an entry option, you will also find playback via Wifi or local network, via DLNA or via Airplay for more comfort. You can also stream your music directly from streaming services like Spotify, Napster, Tidal, Amazon Music or QQPlayer.

The SPDIF inputs benefit from technology derived from the DP-777 AMR with a new solid-state implementation of HV-VFi, a memory buffer and the excellent Global Master Timing system for low jitter. Thus, the buffer data is synchronized with the low-jitter clock system that also drives the XMOS processor and FPGA.

Next-generation XMOS processor: XU216

The new iFi Audio DAC includes a new generation 16-Core XMOS XU216 xCore 200 Series processor. This one has a maximum computing power of 2000 MIPS, and those in double emission, as USB interface. This chip is capable of decoding signals from all available inputs:

• USB : up to 32bit 768kHz & DSD512.
• AES/EBU & SPDIF : up to 24bit 192kHz.
• Wifi, Ethernet, Micro SD : up to 32bit 192kHz & DSD64.

Studio DSD Remastering

While the XMOS chip is very efficient for USB Audio, AES/EBU, SPDIF, MQA or DSD decoding, it is not necessarily the best platform for DSP, digital filters or PCM-to-DSD conversion. This is where the iDSD Pro "Studio DSD Remastering" system comes in. This is extremely effective for upsampling or applying digital filters. A technology based on Crysopeia FPGA dedicated to filters and PCM to DSD conversion up to DSD1024!

External clock

For synchronization in recording studios, the iDSD Pro supports DARS (Digital Audio Reference Signal) based on AES3id, as recommended in the AES11 standard published by the Audio Engineering Society. If you have a good atomic clock, it can be used to improve the iDSD Pro's internal clock system.

Passive filtering and analog stage

The DAC operates in voltage output mode, allowing a DNR of >119dB. All filtering is passive. The device uses a third order symmetric capacitor filter, rather than an active circuit. This makes ultrasonic and RFI noise suppression much more effective.

The analog stage is more precisely a line/headphone stage. It uses a symmetrical and discreet Class A circuit.

Power supply

The iDSD Pro is based on a classic tube design. The DC input current is converted to a high frequency waveform and rectified and filtered through a capacitor filter. This provides a first-level DC bus from which all other voltages are derived. The circuit also generates a galvanically isolated supply voltage for the USB input circuit.

The digital stage is powered by a series of super capacitors totalling 6.6F (6 600 000µF). In this device, iFi chooses ELNA Dynacap Dz super capacitors because they have an input impedance 400 times lower than most other super capacitors.

Individual LDO controllers with local LC filtering from TI provide the final low noise power for all digital sections. A total of 6 individual controllers support the operation of the clock, SPDIF input and DAC section.

For the analog section and especially the tubes, higher voltages are required. Indeed, the stage operates on a 60V rail allowing an extremely wide potential dynamic range. This voltage is generated by the main DC bus and filtered via several capacitor filter stages, the Elna Silmic forming the final stage.

Test et Qobuzissime pour le iFi Audio Pro iDSD

" Superb success and Qobuzissime for this very complete iFi Audio iDSD Pro network player for this - almost - without fail, a pinnacle device in terms of technical design and sound quality. "