[TF1216]

Preview – Pro series - part 1/5
Pro iDSD
Is there anything like it?

Introduction



Over the past few years iFi audio has delighted audiophiles and confounded industry experts with its growing range of high-quality, low-cost and very portable digital-to-audio converters (DACs). Music fans on the move could at last listen to Direct Stream Digital (DSD) on well-built portable devices that didn’t cost the Earth (£500 and under in fact).

Now, iFi is set to rock the digital world again with the launch of iDSD Pro, a ground-breaking Quad DAC that will be used across the next generation of iFi products. Yes, it’s taken a while to come to market but, boy, has it been worth the wait! There is simply nothing like it.

Coming up next, you'll be able to feast your eyes on our Pro iDSD jaw-dropping features. Rest assured that very shortly you'll see what we mean.

Stay tuned!

P.S. This might look like one fine Xmas tease and it is. But then again, it's so much more on top of that, things are going to happen very soon.

[TF1216]

Preview – Pro series - part 2/5
Jaw-dropping features

1) Quad DAC section

The iDSD Pro uses a Quad ‘stack’ of the iFi Bit-Perfect DSD and DXD DAC by Burr-Brown in a custom ‘interleaved’ configuration. This enables a total of eight pairs of differential signals to be used and mixed – that’s four pairs of signals per channel.



While the iDSD Pro includes field programmable gate arrays (FPGA) for digital remastering duties – where we believe they excel – there are also external D/A sections, with a limited number of elements. In the iDSD Pro we use four interleaved 64-Element converters, to create a 256-Element DAC per channel, manufactured at high level of precision.

All signals to the DACs are re-clocked with the low-jitter Global Master Timing® master clock derived from the AMR DP-777.

2) Studio DSD Remastering

Bit-Perfect or Upsampled

All digital processing is Bit-Perfect, without employing an Asynchronous Sample Rate Converter (ASRC), or by up-sampling unless digital filters are explicitly selected. A variety of digital filters (including Bit-Perfect mode without digital filtering) are available.

The iDSD Pro supports both USB 3.0 Type B connections. All inputs (including USB) are galvanically isolated and the USB input is self-powered. The SPDIF inputs use technology derived from the AMR DP-777 including a new, solid-state implementation of the HD-VDi, memory buffer and the Global Master Timing® clock system.

Click on this link for more information on iFi’s SPDIF solution:

http://www.amr-audio.co.uk/html/dp777_tech-papers_spdif.html

Next Generation X-Core 200



The iDSD Pro features the new XMOS XU216 X-Core 200 Series 16-Core processor with a maximum of 2,000 MIPS (two billion instructions per second) calculation power in dual-issue mode as a USB interface. It can decode signals from all Inputs, from USB (up to 768kHz/DSD512), AES/EBU or S/PDIF (up to 192kHz/24Bit) and Wifi/Network/Mass-storage (up to 192kHz/32Bit).

Stay tuned!

[TF1216]

Preview – Pro series - part 3/5
Even more jaw-dropping features

Hi-Res Network Audio



As the flagship in iFi Audio’s formidable fleet of DACs, the iDSD Pro is extremely highly specified. In addition to traditional inputs, it features:

• WiFi/network playback system with leading streaming services (see below)
• MQA decoding onboard for the maximum quality of playback via MQA music files or streaming.
• Wide protocol support including Airplay and USB Memory/Hard Drive/SD Card playback to make a full standalone streamer/network audio player with 32 Bit/192kHz & DSD64 support.

The iDSD Pro gives you plenty of options for playing music online. Here are a few of them:

• Airplay Network Audio Playback from iPhone, iPad, Mac Computers
• Use Digital Living Network Alliance (DLNA) to playback from smartphones, tablets and Windows/Linux computers
• Stream playback from Amazon Music, Audible, Spotify, TIDAL, Napster, Spotify Connect, and QQPlayer
• Playback from Hard disk drive, USB Memory or SDHC Memory Card
• Playback from Network Attached Storage (NAS)

Play direct from SD card



Zero Jitter for all inputs

For all inputs data is sent to the aforementioned Memory Buffer, which iFi describes as ‘large’ and ‘elastic’. Here it is de-jittered to eliminate any transmission of source jitter to the DAC output. The data from the Memory Buffer is further re-clocked by with the low-jitter Global Master Timing® clock, which also drives the X-Core 200 & FPGA.

Click on this more information on iFi’s jitter solution:

http://www.amr-audio.co.uk/html/dp777_tech-papers_jitter.html

Studio Remastering

While the X-Core 200 is favourable for USB Audio, AES/EBU/SPDIF decoding and decoding MQA, DSD, it is not the best platform for DSP, digital filters and PCM-to-DSD conversion. This is where the iDSD Pro’s Studio DSD Remastering system comes in. It excels at handling the Upsampling and Digital Filter duties and has at its heart the Crysopeia FPGA Digital Engine for digital filtering and PCM to DSD remastering, up to DSD1024.



Upsampling in hardware, on board has enabled iFi Audio to overcome the current USB limitation of DSD512 as well as implement multiple filters optimised for specific time-domain behaviour, including that of the DAC and Analogue stage, a level of optimisation not possible in generic software upconversion (as found in Foobar et al).

The five filters available are:

• ‘Bit-Perfect’ No digital filtering is applied, 1 Tap
• ‘Bit-Perfect+’ No digital filtering is applied, 1 Tap
• ‘Minimum Phase’ Minimum filtering, no pre-ringing, minimum post ringing, 32 Taps
• ‘Apodising’ Modest filtering, no pre-ringing, modest post ringing, 128 Taps
• ‘Transient Aligned’ Max filtering, max Pre-Ringing, maximum Post-Ringing, 16,384 Taps

Stay tuned, there's more!

[TF1216]

Preview – Pro series - part 4/5
Jaw-dropping features - the story goes on...

Full Galvanic Isolation

All inputs are galvanically-isolated (including USB). As found in the AMR DP-777.

The USB Input is self-powered and does not draw power from the USB bus, making it impervious to after-market add-ons or tuning accessories.



Cutting-Edge SPDIF technology

The SPDIF etc. inputs use the technology derived from the AMR DP-777, including a new, solid-state implementation of HD-VDi, memory buffer and the Global Master Timing® clock system:

http://www.amr-audio.co.uk/html/dp777_tech-papers_spdif.html
http://www.amr-audio.co.uk/html/dp777_tech-papers_jitter.html

The SPDIF etc. inputs are not expected to benefit much from any kind of tweaking or tuning gizmos.

External Clock options and Synchronisation

For synchronization in recording studios the iDSD Pro supports AES3id based DARS (Digital Audio Reference Signal) as recommended in the Audio Egineering Society’s published AES11 standard. And if you happen to have a really good atomic clock (at least a Sanford Research Systems PERF10 should be used) this can be used as to further elevate the iDSD Pro over the internal clock system.



Yes, this is hugely over-specified but the iFi flagship deserves it.

Passive Filtering and Discrete Analogue stage

The DACs operate ‘Voltage Output Mode,’ giving >119dB dynamic range. All filtering is passive, using a fully-balanced third order capacitor/inductor/capacitor filter, rather than active, feedback-based circuits, to remove ultrasonic noise. (Active filters struggle with the amount of ultrasonic noise and RFI they have to handle and at a few 100kHz they can lose the ability to filter noise at all, which is precisely where a lot of noise is present.)

Using passive CLC filtering directly after the DAC means that the following analogue stage is not required to handle ultrasonic noise and RFI originating from the DAC process. Directly after the DAC and filter is the analogue domain volume control, which uses a six-track Alps Japan potentiometer. This can be bypassed for the line outs.



The analogue stage is more precisely a line/headphone driver stage. Using Class A circuitry, it is fully-balanced, fully-discrete, direct-coupled (coupling capacitor less) and Tube/Solid-State user-selectable.

Stay tuned, there's more!

[TF1216]

Folks, we were able to catch our Skin the skunk lady for a short iDSD Pro related Q&A session.



Who knows? Maybe in the future she'll be able to give us even more insight about the product itself? In the meantime, here goes...

• Us: People ask how we do USB galvanic isolation on the Pro. Is it the same as iGalvanic? A trickle-down perhaps?

Skin: No, in the iDSD pro we operate very differently. We use a suitable isolation barrier between the digital (noisy) section with XMOS, WiFi/networking, the Chrysopeia FPGA and the DAC's / Reclocking / Clock. In essence, all noisy digital processing is confined to a blocked of "island" on it's own board and isolated from all audio circuitry.

This parallels the way in which i.e. the JVC K2 system is implemented for playback and the isolation of the DAC from digital noise found in the legendary Marantz CD/DA-12 system featuring the TDA1541. All this is essentially trickle-down from the DP-777.

The iGalvanic isolates the USB connection instead, so it is a less complete solution which can't isolate noise inside the DAC itself.

• Us: And what clocks do we use?

Skin: We use the same proprietary GMT clock system as originally developed for the AMR DP-777. Please see here to know more:

http://www.amr-audio.co.uk/html/dp777_individual.html

• Us: Are there digital outputs on the Pro?

Skin: No, what would be the point? This device was designed as a d/a converter above all else.

• Us: What is the RJ-45 output for?

Skin: It is not an output, it is a connection to your local area network (LAN). For reliable streaming, especially for high resolution audio wireless networking can be frustrating with dropouts and glitches.

If streaming hi-res content from a NAS or a server on your home network, a hard-line network connection is preferred over WiFi.

• Us: Does the iDSD Pro use an OCXO clock?

Skin: No, baking a crystal merely reduces long term thermal drift (over periods of minutes to hours) which is inconsequential to audio playback. We employ a high quality miniaturized 10MHz discrete crystal (not canned oscillator) as timebase for our GMT clock system.

The GMT clock system allows the clock frequency to be set with appx. 0.01ppm (parts per million) or better than 0.5Hz accuracy compared to the nominal 45/49MHz audio clock frequencies

• Us: Skin, many thanks!

Skin: Yup, anytime, but not too often as I have things to do!

[dburna]

Way cool, and lots of great information, but do you have:

1. Availability ETA?
2. Est. Price?
3. Additional pictures (especially the back)?

Thanks,  -dB

[TF1216]

Way cool, and lots of great information, but do you have:

1. Availability ETA?
2. Est. Price?
3. Additional pictures (especially the back)?

Thanks,  -dB

• 1st Quarter - Finally!
• ~$2,500
• Let me work on that 

[mresseguie]

Okay. I'll take the bait.

Will one be ready in early February? I'd like one to take to an upcoming get together near Seattle. There will be a half-dozen audiophiles who would love to be impressed.

Contact me.

Regards,

Michael

[TF1216]

Okay. I'll take the bait.

Will one be ready in early February? I'd like one to take to an upcoming get together near Seattle. There will be a half-dozen audiophiles who would love to be impressed.

Contact me.

Regards,

Michael

Hi Michael,

Unfortunately, not one of the Pro iDSD will have arrived in the States by early February.  Sorry man!

I am interested in your gathering though.  What kind of fun stuff will be in attendance?

[mresseguie]

Bummer. I suspect we could hold another G2G in May with the right incentives. 

The following goodies ought to be present for February's G2G:

One custom built KICK ASS to-die-for dedicated listening room
GR Research OB speakers (forgot the model) with dual 12" bass units
Daedalus Apollo speakers (possibly)
Don Sachs Model 1 6SN7 preamp
Don Sachs KT88 Kootenay 120
Mivera 1200as Iceedge amp
MP-D2 DAC upgraded with Mundorf caps (possibly)
DB Audio Labs Tranquility SE DAC with Jupiter Cu caps
Lampizator Atlantic DAC
Yummy food and choice alcohol

There may be other goodies depending on who attends and on what they decide to bring.

It ought to be a lot of fun. This will be our third G2G.

Michael
 

[TF1216]

Preview – Pro series - part 5/5
Jaw-dropping features - the story ends

Power Supplies

Using classic tube design, brought up-to-date with 21st Century technology, all incoming DC is converted to a high-frequency waveform then rectified and filtered by a choke input capacitor filter. This produces a first-level DC bus from which all further voltages are derived. The circuit also generates a galvanically-isolated power supply voltage for the USB input circuitry.



The digital section is powered by a bank of Super Capacitors totaling 6.6 Farad (6,600,000uF). iFi uses Elna Dynacap DZ (TM) Super capacitors because they have a 400 times lower internal impedance than common grades of super capacitors.

Individual low-noise TI LDO Regulators with local LC filtering provide the final low-noise power for all individual digital sections, a total of six individual regulators cover Clock, SPDIF Input and the DAC's digital section.

For the analogue stage (especially the tubes) higher voltages are needed. The whole stage effectively operates on a 60V rail offering massive potential dynamic range.

The USB input section has its own separate power management system with multiple regulators and filtering operating from the galvanically-isolated voltage generated to power this section.



For the analogue stage, higher voltages (especially for the tubes) are needed. The whole analogue stage in effect, operates on 60V rail, giving massive potential dynamic range. These are generated from the main DC Bus and filtered using multiple stages of inductor/capacitor filters, with Elna Silmic Capacitors forming the final stage.

Every section in the iDSD Pro has received massive attention to detail and combines classic design techniques for tube equipment with state-of-the-art technology to deliver extreme performance.

iDSD Pro Features

Sample Rates:

• PCM up to 768kHz
• DSD up to 24.576MHz
• DXD and double speed DXD (2xDXD)

Studio DSD Remastering:

• PCM 705.6/768kHz (from all PCM sample rates)

Crysopeia FPGA Digital Engine:

• DSD 512/1024 (22.5792 - 49.152MHz) user-selectable

Inputs:

• USB (required for DSD, DXD and sample rates above 192KHz)
• Wifi – Linkplay
• Ethernet – Linkplay
• USB-Memory/Harddrive – Linkplay
• SDHC Memory Card - Linkplay
• AES3 (XLR - single link)
• SPDIF (RCA/Optical combo)
• BNC multifunction In (SPDIF/AES3id In, DARS In, 10MHz In, Atomic clock in
• BNC multifunction Sync Out (DARS out, 10MHz out)

Outputs:

• 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 2.3V, 5V or 8V maximum
• Headphones BAL 3.5mm Jack at 4.6V, 10V or 16V maximum
• Headphones out 1,500mW RMS X 2 @ 64 ohm, 4,000mW max. 2 X @ 16 Ohm

Volume Control:

• Balanced (quad) Alps potentiometer, motorised with IR remote control
• XLR/RCA outputs can be selected as fixed level or adjusted
• 6.3mm Headphone Jack is always adjusted

Other Functions:

• Various digital and analogue filters can be selected for DSD and PCM up to 192KHz

PCM Filters:

• Bitperfect (no digital filter, minimal analogue filter)
• 44.1 - 192KHz, always used for 352.8 - 768kHz

• Bitperfect II (no digital filter, analogue filter corrects HF rolloff)
• 44.1 - 96kHz

• Minimum Phase (Filter has no pre-ringing and minimises post-ringing)
• 44.1 - 384KHz, 32 Tap

• Apodising (Filter has no pre-ringing and moderate post-ringing)
• 44.1 - 384KHz, 128 Tap

• Transient Aligned (Filter has extreme pre- and post-ringing)
• 44.1 - 384KHz, 16384 Tap

• additional fixed 3nd order analogue filter @ 100kHz

DSD Filters:

• fixed 3rd order analogue filter @ 100kHz, compensation for 6dB level difference between DSD & PCM

[pfarthing]

Very impressive. Can this function as a DAC/pre-amp straight into a power amp? Also, to be clear, if I'm using say a standard laptop as a source, does this mean things like iDefender, iUSB3, iPower, iGalvanic, Mercury and Gemini cables would all be unnecessary?

[TF1216]

The story about digital filters ...
... as we see it

Alright, let's be frank about one thing...

ALL FILTERS ARE WRONG. ALL OF THEM, INLUDING THE 'NO FILTER' OPTION.

The reason is that such rules like Nyquists's law sampling theorem are true, but are limited by strictures that make them not directly applicable to highly variant signals (e.g. music) which may contain content that can't be resolved into finite numbers of sine-wave wavelets.



Digital filters are based on steady state mathematics and thus distort the music signal, primarily in the time domain. This is an unavoidable byproduct of their function. Operating without filter distorts the music in a different way.

Many publications offer good reasons why a specific form of digital filter is superior. Usually the reasons are based on theory and in how close a given filter implementation comes to such a theoretical ideal.

What is commonly omitted and ignored are listening tests of radically different filters with different types of signals.

All digital filters (including non) differ in how they are wrong and how this influences objective measured performance as well as subjective listening performance with music and indeed specific music.



Music with a highly percussive nature and many instruments containing non-harmonic sounds (i.e. Jazz or Pop) will react different with a digital filter than music which is based mainly on pure tones and harmonics (i.e. a string ensemble plus a soprano singing).

These distortions become all the more relevant and carry greater possible audible consequences, the lower the sample rate. So the most abundant digital music source - CD quality - is most impacted.

Wherever there is a difference, there is also a preference. Subjective listening preference may be informed by a learned or acquired response to recorded sound (e.g. what sounds "right" or "hifi" is not what sounds natural in comparison to a live performance), in addition to direct referencing acoustic music performances.

So, no matter what single fixed filter is present, it is wrong and may not be preferred by a customer at least not with all music. What AMR implemented in the DP-777 (...and now iFi audio in the Pro iDSD) is to give a user a choice between the CORE possible approaches to digital filtering that we have found to produce meaningful differences and preferences in listening.



We offer the option to bypass digital filtering completely, to select minimum phase filters of differing structure (minimum ringing or apodising) or to select a "transient aligned" FIR filter that offer a maximally long filter response and number of taps to come closes to the idealised textbook filter.

Hence we do not prescribe ONE singular 'perfect' approach, we offer the choice between different approaches that have all been declared by their respective proponents to be 'perfect' and leave the choice which kind of 'perfection' is preferred to the customer.



Note, not everyone is sensitized to the differences digital filters make. Whatever your preference, simply choose what you like based on either what you believe to be right or on what sounds best to you. We do recommend to experiment with filters at least occasionally, especially once listening to different styles of music than usual.

Stay tuned, coming up is Pro iDSD's digital filtering!

[TF1216]

The iDSD PRO offers the following choices of digital processing:

I. Direct - Bitperfect
Both PCM and DSD signals are not processed in any way.
For PCM this is effectively what is sometimes called "non-oversampling" or "zero-oversampling", for DSD it means DSD is retained in the original DSD format and directly converted to analogue without any digital processing.

II. PCM - upsampling
In this case PCM is up-converted to 16 X PCM (705.6/768kHz) using a choice of digital filters (Minimum Phase, Apodising, Transient Aligned) that offer different tradeoffs of time-domain and frequency-domain performance.
DSD remains completely unprocessed.

III. DSD - Remastering
In this case all incoming audio (except DSD512) is converted to either DSD512 or DSD1024 as selected, using the filter selected (including Bitperfect, meaning no digital filtering is applied).
All the above mentioned digital processing options apply to all sources, including the network audio bridge and AES/EBU & S/PDIF inputs.
Inputs other than USB are currently limited to maximum sample rates of 192kHz PCM and DSD(64) via DoP.




In the nutshell, when:
DSD512 Remaster is selected, then all audio (except DSD512) is upconverted to DSD512.
DSD1024 Remaster is selected, then all audio (yes, DSD512 as well) is upconverted to DSD1024.
The upconversion process allows different digital filters, including Bitperfect (no filter), to be selected.



For example, this image shows the screen in DSD Remaster DSD1024 mode with a 44kHz input signal being upconverted to DSD1024 (45.158MHz) using the Bitperfect filter.

[Tyson]

Well I'm ordering one.  I'm super excited for a few different reasons:

1. Clutter cleanup!! Right now I have 3 different DACS in my system.  One DAC for my hirez music on my PC server, one DAC for my 4k Blu Ray player to plug into for movies, and one DAC for my Roku device (it also does wireless streaming for blue tooth).  Each DAC also has power filters in front of it and signal clean up devices in front of it, etc, etc, etc.  It's a mess!!!  The iDSD Pro will let me clean up ALL of that and have one device to handle everything, that's awesome!

2. Tubes!!! It's not touted enough here, but to me having a tube based output is HUGE!  IMO the more tubes in a system, the better.  I can't wait to hear what it sounds like. 

3. DSD - I have tons and tons of DSD recordings, the fact that this handles ALL of them natively is phenomenal.  I'm a big fan of DSD.  IMO the best DSD matches and even surpasses the best Vinyl.  That's NOT true of PCM.  The best PCM is "almost" as good as the best Vinyl, but still falls just short, IME.  Still I'm also excited to hear what the iDSD Pro can do with PCM - maybe there is in fact a way to dial it in to get those last couple percentage points worth of difference/

4. Fully differential!!!!!! This is huge for me because I have crazy sensitive speakers (97db) and ANY noise in my system becomes painfully obvious.  The iDSD Pro should get me that one thing I crave above all else - silence

OK there's other things I'm excited about too, but that's enough for now.  Can't wait for it to get here.

[dburna]

So, is there going to be an iDSD tour?  If so, count me in!!   

Best,  -dGB

[debjit.g]

when is this available in the US ?

[TF1216]

Very impressive. Can this function as a DAC/pre-amp straight into a power amp? Also, to be clear, if I'm using say a standard laptop as a source, does this mean things like iDefender, iUSB3, iPower, iGalvanic, Mercury and Gemini cables would all be unnecessary?

The Pro iDSD is a functioning pre-amp.  However, the Pro iCan would be more suitable in the role if one was already in the chain.

The Pro iDSD does not require the iDefender, the iUSB3.0 or iGalvanic.  The concepts found within these devices have been incorporated into the Pro iDSD.  However, the implementation of the concepts took on a radically different approach with deeper integration into its design opposed to simply applying the technologies on the inputs.

I don't have a good answer regarding the USB cable portion of your question.  I have yet to get a Pro iDSD myself to try different USB cables.  Also, USB cables always surprise me depending on the system they are used in.  I have heard USB cables be winners in some systems and not stunners in others.  Sorry man to drop a dud on you with this one.

[TF1216]

So, is there going to be an iDSD tour?  If so, count me in!!   

Best,  -dGB

No tour but I believe I will have a couple to loan out.  May I put you on a list of folks to contact once the units arrive?

[TF1216]

when is this available in the US ?

Within the next 30 days