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iFi Audio skunkworks....micro iDSD. Crowd-Design - by you, for you

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Crowd Design Outta This World #3: Turbo

Over at Head-Fi, we have just announced the 3rd most exciting, "OTW" feature. It is the Turbo headamp option which gives a whopping "8.0V max/4,000 mW @ 16 Ohm."

 

Put it this way, the micro iDSD will drive the HiFi Man HE-6 to 108dB. That is moving some serious air!

 

And Super Duper feature 1.7 "SmartPower" to recharge your iDevice from the micro iDSD!

 

Hope you had as much fun reading this as we did developing these features after your Crowd-Design suggestions.

 

cont'd

Crowd Design Outta This World #3: Turbo

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Crowd-Design: Power Supply (i) The Meaty Monster is Power Mad!

 

The power supply is the heart of every audio device. It provides the power which is modulated into audio signals. One just cannot take too much care to the power supply. Within the breast of the beast that is the "Meaty Monster" beats two hearts. And they beat very, very fast. And they draw their power from one of the biggest batteries found in any portable audio device.

 

350x700px-LL-31c5acae_godzilla2hearts_zps2e9e73cf.jpeg

 

A. The poor old standard 500mA USB port …

In the micro iDSD, we need a lot of power, to produce one of the most powerful headphone amplifiers fitted to ANY DAC/Headamp, never mind a portable one. Our 18Watt/Hour Lithium-polymer can deliver 18 Watt for one hour, or 1.8 Watt for 10 Hours. That is a lot of power.

 

But standard USB ports are limited to 500mA! This issue not something unique to us, to deliver 1W per channel and power the DAC, clocks and the XMOS USB interface, 500mA are wholly insufficient.

 

"Intelligent Power-Path" (IPP):

A standard USB port offering 500mA is only sufficient to operate the iDSD micro in “xxx” mode (you have to wait for upcoming OTW#2), without leaving any current to charge the battery.

 

Hence for the micro iDSD, when on USB power, we have developed the special "Intelligent Power-Path" (IPP) battery charger will use battery power to "backup" USB power if more current is needed. So, the micro iDSD will dip into the battery backup to sustain power peaks. This is somewhat like a hybrid car that uses the petrol engine if and when required.

 

 

B. “With such a humongous battery, it will take ages to recharge!”

This is why we integrated a special circuit to detect the attachment of dedicated charges and the special high power USB ports found on many modern computers. The micro iDSD can detect these ports and then can take advantage of the so-called BCP-1.2 standard, able to play audio AND draw 1,500mA from the computer, not just a measly 500mA. This way in normal operation the battery can recharge in only around 5 hours while simultaneously playing music.

 

C. High Power output needs High-Voltage

In order to deliver a powerful headphone output, a powerful and high-voltage power supply is needed. With Lithium-ion batteries limited to around 4.2V maximum, it would mean to either use 8 batteries in series (which requires a lot of space and very complex charging systems) or use some form of power conversion to step-up a single battery voltage to the voltages needed.

 

D. Can I have both Positive and Negative voltages too please?

For uncompromised audio performance, a dual supply with positive and negative voltage is a must. Hence we use power converters to create a symmetrical PSU adjustable from ±4.5V@1,000mA transient to a maximum ±13.5V@500mA.

 

Our first take producing this analogue dual-rail power, using a theoretically very neat design just did not work right, never reaching design efficiency and had to be abandoned. This was the problem we highlighted a month ago.

 

Our next take was to cascade two converters, first one to make an adjustable positive voltage at twice the current required and then a second to invert this power line to provide the negative voltage.

500x1000px-LL-5b10e931_photo1t_zpse9c5ee9b.jpeg

 

This circuit alone is quite challenging (in fact, very challenging), while many power IC's are on offer, very few are fast enough for our needs and even fewer allow the output voltage to be adjusted in real-time! We had to find a chip (we went through more than 100 different ICs) that is sufficiently flexible to allow us to use a rather neat design trick – so we can adjust the output voltage of this converter from our 32Bit ARM Cortex CPU, which has a 12-Bit DAC built-in.

 

This way we can adjust the output voltage between 4.5V and 13.5V in over 4,000 precise steps. This chip operates at around 95% efficiency at 0.64MHz and uses a very small PCB area with a solid ground plane and a shielded choke, so very low radiated noise.

But this leaves us with only a positive supply, no negative line. The next step was to find a way to invert this positive power line.

Again, there is no simple off-the-shelf option; we had to use another "undocumented feature" to create a servo-controlled power converter that precisely inverts the positive rail, so by adjusting the positive rail the negative rail follows precisely to within 1-2mV!

500x1000px-LL-2e03d6e7_photot2_zpse5936d14.jpeg

Note: Servo-controlled power converter normally only used in $$$$ equipment like the AMR PH-77 (Euro12k/US$12k).

 

 

cont'd

iDSD micro Crowd-Design. Software Design Notes (4). No ordinary DSD - page 56 - Page 52

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micro iDSD: Software Design Notes (4) DSD – No ordinary DSD

 

The recent discussion about chipsets and what constitutes what prompted us to bring in part 4 of the Software Design Notes. (also the AudioStream interview is quite heavy going as Thorsten does like the details).

 

Mainly - why we chose the Burr-Brown and use an analogue volume control (we avoided using a digital volume control).

 

There is DSD playback and DSD by iFi which we believe is different. We are really pleased with our DSD implementation - it really is quite one of the most original DSD implementations out there. At the core, no data conversion and manipulation is done INSIDE this chip, so the DSD data is preserved Bit-Perfectly. An analogue filter is applied to the DSD data before it is sent to the output stage.

 

For us, "doing digital" means keeping the signal path original as much as possible; ideally from the ADC being DSD kept through to DAC being DSD (the same of course goes for PCm which we will cover later).

 

But in the case of the nano iDSD and micro iDSD, we have this:

350x700px-LL-51257985_BB-DSD_zpsb8342a0e.png

 

Therefore, when playing back an originally-recorded DSD file through this Burr-Brown chipset on the iDSD, the listener has ensured that the WHOLE ADC > DAC path has remained native” in its DSD format. Like this:

500x1000px-LL-ff26fa3c_DSDnativepath_zps1688deec.jpeg

 

The DSD chip we use is under full software control in order to gain access to many “undocumented features” (yes, they all have them). What are those “undocumented features”, we will announce them (a few should be a world’s first) closer to when we officially launch the micro iDSD.

 

Compared to the lion’s share of DSD-capable chips out there, most of them perform data conversion and manipulation of the DSD data and hence are no longer Bit-Perfect. This maybe the designer's choice, which is very much their prerogative but for us, we just about make it our mission to avoid such conversion processes.

 

Why? - conversion from one format to another is lossy. Hence to us, this is best avoided as much as possible.

 

What is the giveaway? If they do digital volume control on the DSD stream, this is very likely to convert the DSD data into NON-DSD data (does not necessary mean that they are converting into PCM, but converting into something non-DSD at the very least).

 

Even Pro Audio Studios use DAWs that convert

Pyramix do not even pretend to use DSD, in their DAW any processing means the DSD signal is converted to DXD (24Bit/352.8KHz) and processed as this, then converted back to DSD.

200x400px-LL-de3bbb6c_Pyramix-Masscore-at-Liverpool-Institute-for-Performing-Arts_zpsa1124ad4.png

 

And Sonoma converts to DSD wide (aka PCM narrow), then applies a 24Bit scaling factor, ending up with 32PCM which is then converted back to DSD (remodulated from PCM).

200x400px-LL-d50b9823_HiattSOM2_zps9e2ecdc8.jpeg

 

It means that any processing of DSD in either Sonoma or Pyramix converts DSD to a form of PCM. Only "Tape Splice" (this refers to physically cutting the old magnetic tape and splicing two different tapes together) style edits can be done while retaining DSD.

 

If these VERY expensive DAW (Digital Audio Workstation) music recording/production packages cannot fade/volume control DSD without turning it to PCM, this begs the question of how come mainstream and far less costly commodity DAC's chipsets can?

 

This comes full circle back to why we selected the Burr-Brown chipset AND central to this why we use an analogue volume control (which yes, also has its issues but to us, these are far less sonically-damaging).

 

cont'd:

iDSD micro Crowd-Design. OTW#2 Perfect-Match with Power modes+iEMatch! (page 60) - Page 56

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micro iDSD: Outta This World #2: Perfect Match with Power Modes and iEMatch.

 

Background

In any audio system, the matching between the amplifier and the transducers is arguably the most crucial.

 

In the loudspeaker market, speaker + amplifier matching is typically well-matched.

i.e. low-powered amplifiers are paired with high-efficiency speakers and vice versa.

 

HOWEVER, in the headphone market, the gamut of headphones paired with headphone amplifiers is very inconsistent. This often leads to poor-matching from not enough power to drive headphones (typically: unimpressive sonics) to far too much power to drive in-ears (typically: unusable volume control + excessive hiss).

 

Explanation

In the headphone market, we went through virtually every current production headphone out there and what we found shocked us.

 

Running the ruler over current production headphones, we found that there is a massive 53dB difference between the most efficient In-Ear-Monitors (IEMs) and the most inefficient headphones. This is an absolutely enormous range (think of this as the difference in loudness between a disco and a quiet library so this is NOT subtle.)

 

At one end of the spectrum is the HiFi Man HE-6 which is as hungry as things go. Rated at 90dB/V, this “Hummer” of a headphone needs well over 3,000mW to drive properly to good levels. Let’s categorise these as low-efficiency headphones.

 

BTW, for the K1000 die-hards out there, it is the "Mack juggernaut" as it is rated crazily low at 84dB/V!!!

 

At the other end of the spectrum are super-efficient IEMs. The Sennheiser IE800 is rated at 143dB/V and even driven by the iPhone’s paltry 15mW, you can only dial-up to 50% of its digital volume before it starts to encroach upon ear-damaging levels! Let’s categorise these as ultra-sensitive IEMs.

 

It is not surprising to find that we had yet to come across a headamp that can deal with this gamut let alone a DAC headamp that is portable that can deal with this full spectrum of headphones! :regular_smile :

 

Note: dB/mW cannot be compared directly, we have normalised all headphone sensitivities to 1V signal, which is close to the maximum output of an iPhone, incidentally.

 

 

How best to consider the max power output and the perfect headphone pairing?

The micro iDSD has max power output of 4000mW.

 

The Porsche 911 Turbo S, has a maximum power output of 560bhp. To put all that power down onto the tarmac and to ensure that it grips the road to very best ability of the driver’s demands, it has Sport Plus/Sport/Comfort (see Sport buttons below). To zero-in that perfect-setup, the Porsche Dynamic Chassis Control (see PDCC button below) further fine tunes the whole of the car’s drivetrain to ensure maximum grip.

350x700px-LL-79c20f9f_turbo-controls_zps44279dac.png

 

The micro iDSD has Turbo/Normal/Eco and in conjunction with iEMatch, the listener is able to dial-in the IEM/headphone used.

 

Unleash the beast! (we mean the micro iDSD + your headphones, not the 911 Turbo!)

 

How does this benefit the listener?

OTW #2 is the perfect-match of headphones with the micro iDSD.

500x1000px-LL-f173e1f9_HeadphonemodesieMatch_zps0da6a0e4.jpeg

 

For the very first time ever, from the Sennheiser IE800 > HiFi Man HE-6, the listener is able to “dial-in” the perfect match using a combination of the micro iDSD’s Power Modes + iEMatch.

 

For example:

HE-6: Power mode = Turbo and iEMatch = Off

IE800: Power mode = Eco and iEMatch = Ultra-Sensitivity

 

These are of course, the two polar opposites so with any other headphone or in-ear-monitor, then adjust the different settings under Power mode + iEMatch to suit.

 

cont'd

iDSD micro Crowd-Design. Super Duper feature 2.0: XBass, the Ace of Bass (page 65) - Page 60

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The R&D team asked us to update you:

- testing pretty much complete

- all the really difficult stuff in software control works a treat

- just a few minor bugs to squash...

 

From the production dept:

i) Early July - the micro iDSD ships out

ii) Mid-July - in store and available for pickup (around the world simultaneously.)

 

We shall update with the global launch date once we know when all our major retailers are likely to them in store.

 

So no major delays of months or anything.

 

Full speed ahead!

 

cont'd

iDSD micro Crowd-Design. Super Duper feature 2.1: The CCK/OTG port High-Fidelity on the go! (page 67) - Page 63

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Some of you with experience of the nano or micro iCAN will already be familiar with our XBass feature in the upcoming micro iDSD.

 

But for others, we hope you find this interesting.

 

Super Duper feature 2.0-XBass (not all headphones are created equal)

 

Background

“Listening to the radio I feel so out of place

There's a certain something missing that the treble can't erase

I know you can tell just by looking at my face

A word about my weakness I'm totally addicted to bass”

 

The Puretones – “Totally Addicted to Bass”

 

 

No one headphone produces a perfect bass response.

 

Explanation

Between different recordings and different headphones, bass is often found wanting.

 

To have Bass or not to have Bass, that is not the question here

Listening to great music is always a positive experience; from the most humble to the most extravagant system, all are capable of providing great enjoyment. However just as in the song by the Puretones, if the Bass is not right, then “There's a certain something missing that the treble can't erase”.

 

With headphones, bass performance varies widely. Some headphones have prodigious bass, some have perfect, even-handed bass, yet many others are bass shy or have severely missing bass. There is no direct link to cost in this, some rather inexpensive headphones can have killer bass, while rather more expensive headphones are found lacking. Of course, bass performance is only ONE factor in Headphone sound quality.

 

Here are some representative frequency responses of different headphones:

500x1000px-LL-b239d483_XBass_zps8c6e55c8.jpeg

 

 

Leftmost is the Ideal curve, this is what a headphone SHOULD measure like. Real ones never do. The other three are examples of REAL headphones and show their varying degrees of bass response.

 

Going from second left, real world Example 1 has very good real bass. Such headphones are quite rare though.

 

Example 2 has some attenuation in the bass. This is often found even with rather expensive headphones. This curve is indicative of a certain US$ 1,500 Headphone which is all around excellent and of the best ever made, yet the bass is still a little lacking, not that one would call it bad, but always leaves one wishing for more.

 

Example 3 is typical of many smaller headphones. Bass is noticeably absent; not just a little at the very bottom, but a big chunk has gone AWOL. Such headphones do sound distinctly lacking in bass; thin, weedy and unsatisfying. They make some correction mandatory.

 

Another possibility that is not shown is that the headphone will have a very heavy, boosted bass, some DJ Headphones and some in-ear-monitors types are like this. Depending on music and taste this may be perceived as a good thing, or not. For such headphones it is very important that the headphone amplifier has a very good damping factor, so that the extra bass is well-controlled without becoming boomy. To show what actual, real headphones look like, below is a comparative shot of four different ones measured by HeadRoom.

500x1000px-LL-10b499f6_headroomgraph_zps08df6ba9.png

 

 

At iFi we have been aware of this common bass problem with many headphones. Oddly, headphones with the best bass are rarely those with the cleanest midrange or the best imaging. Hence buying headphones is often a compromise.

 

i) One could buy a set of headphones that has almost everything and give up a bit of bass. With the player software, the equaliser function could be adjusted to compensate for the lack of bass. But this brings into play DSP and the music signal is no longer Bit-Perfect.

 

ii) And of course, with your iPod or Laptop, the limits become obvious: the limited power output simply cannot supply the extra power needed for the equalised bass and sound becomes distorted, so you have to turn the volume down, but you do regain some lost bass. It still often does not sound that natural either, as few of these equalisers are correctly tailored to compensate for the shortcomings of headphones…

 

Enter XBass...

 

How this benefits the listener

If your headphones leave your craving for deep, clear, solid bass unsatisfied, you need something eXtra. You need eXtra-Bass. XBass - adds back the "missing bass" and the customer is able to dial-in their desired level. As with other iFi features, this is performed in the analogue domain so the music signal remains original.

 

Further, as XBass is integrated in the micro iDSD Headphone Amplifier we have more than enough power to add the bass back without distortion - the extra bass is tight, crisp and precise.

350x700px-LL-2c7642f6_endcapXBass_zpsc59ad602.jpeg

 

 

XBass is integrated into the micro iDSD (along with nano and micro iCANs). Just flick the switch to ON and away you go. If you find it doesn't suit a particular headphone or track, just switch it to OFF.

 

Wanna make your 'phones the Ace of Bass? then checkout XBass...

Edited by Stereo_Electronics

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Super Duper feature 2.1 - The CCK/OTG USB port

500x1000px-LL-5dfc3103_photo36_zps1b3de178.jpeg

 

Background

Nowadays, high-fidelity portable audio is on the rise and shows no sign of abating. If you just look around and see how many IEMs there are, it gives you a sense of the sheer number of users who want audio on the move.

 

For the micro iDSD Crowd-Design, the CCK/OTG connection came up. And so now you have it.

 

Explanation

To use a Smart device as a portable transport + DAC, there are two options:

 

1. Apple - has the Camera Connection Kit (CCK) is the previous, 30-pin version. The newer USB Adapter is the 9-pin version. But both are essentially the same.

 

2. Android - Samsung has the On-The-Go (OTG) cable.

 

Both the CCK/OTG have the proprietary manufacturer connection at one end and the USB type A socket at the other end.

200x400px-LL-0e53fbf2_photo35_zps979cd5ab.jpeg

 

With USB type A socket, this NORMALLY goes to a short USB cable and then connects to the USB Type B port (as most DACs have this port).

 

With the micro iDSD, there is no need, the CCK/OTG cable can be connected directly to the micro iDSD as it has a type A plug.

 

Like this:

350x700px-LL-cacb4dc9_photo29_zps9eecf774.jpeg

 

When you are home on a desktop/main system, you just use either of these USB adapters (both are to be found inside the micro iDSD box) to connect the USB cable > micro iDSD

350x700px-LL-1d7a783b_USBadapter1_zpseca50f22.jpeg

 

How this benefits the listener

Now you get the best of both worlds with unrivalled convenience:

 

Portable audio = Smart device + CCK/OTG + micro iDSD > IEMs

 

Desktop/Home audio = Computer + USB Adapter + micro iDSD > Headphones/Amplifier

 

 

Addendum:

For Apple - the playback players range from iTunes, Onkyo HF Player, Capriccio and Hibiki.

For Android - best stick with the most ubiquitous which is the USB Audio Player Pro UAPP.

 

You can open a, iFi support ticket (iFi-Audio :: Support Ticket System) and we shall email the pdf to you concerning these connections.

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Crowd-Design. Software Design Update (5) - Three filters each for PCM and DSD. Enjoy..

 

Digital and Analogue Filters - have it your way

 

High-end selectable digital and analogue filters on a portable DAC this size is very rare, let alone 6 (3 digital ones and 3 analogue ones!)

 

Most of these filters were trickled-down from AMR’s CD-77 (USD11,400) and DP-777 (USD5,000), so the development cost has already been amortised which has benefited iFi and the micro iDSD.

 

 

3 Digital Filters (for PCM)

Bit-Perfect

Minimum Phase

Standard

 

The Standard filter – does as its name suggests and it “measures the best.”

 

The Minimum Phase (MP) filter - greatly reduces the unwanted pre and post-ringing of the digital signal and produces a more natural sound. This is the “Super” digital filter for most high-end DACs.

 

The Bit-Perfect filter – as Jose Mourinho coined, is the “Special One.” It originated in the CD-77 (where we called it Digital Master mode), then on the DP-777 (Bit-Perfect mode). This is the mode that gives the most organic sound. This not only comes from just us but all the users of the CD-77, CD-777 and DP-777. After playing around with the other modes, this is the mode they settled on and don’t have any urge to alter, this mode is highly-addictive. It really does compare to vinyl done well.

 

Now the micro iDSD features all 3 of these high-end digital filter modes thanks to AMR.

 

 

3 Analogue Filters (for DSD)

Top of the range SACD players (SACD is DSD) do have selectable analogue filters, but most DSD capable DACs don’t have any selectable analogue filter, why?

 

Because for most DSD capable standalone DACs, DSD is only afterthought, hence no selectable analogue filters. However, the micro iDSD was designed ground-up as a native DSD (and native PCM) DAC, DSD is not an afterthought at all. We even name it “iDSD” :smile:

 

Actually, back in the nano iDSD, we already had selectable analogue filters for DSD playback.

 

In the micro iDSD, we are just bring this to another level and implemented 3 of them:

Ultra-wide Range

Extended Range

Standard Range

 

There is no “best” one, just pick the one that you like to listen to the most. To us, the most important thing is to have the freedom to have it your way, like that well known “foot long” sandwich.

 

Not 3 Donuts, but 3 Footlong sandwiches

350x700px-LL-ab5111e9_footlong_zps7a163dbd.jpeg

 

Having said that, we do like the Ultra-wide Range one but this may not work for everyone, as some of the amplifiers out there don’t like this kind of ultra-wide band width and may produce an unpleasant noise (no damage will ensue).

 

 

Digital Filters - Reload

With iFi, even though we bring up measurements, you will often find we always say, they are more exclusive than mutual: each should be taken in their own right.

 

Which digital filter is more relevant to measurement and which one is more relevant to listening to music?

 

To answer this question, we must bear in the mind that the following:

A Sine wave is more useful for measurement and testing, a music signal is more impulse-like.

 

So if one wants to measure the performance of a DAC, we recommend using the Standard filter, which give the “best performance” on a sine wave signal.

 

However, for normal real-world listening, the Minimum Phase filter will be a more accurate reproduction of an impulse signal when compare to a Standard one; however the most important thing to note is that the Bit-Perfect filter will give the MOST accurate reproduction of an impulse signal.

 

i.e. for the most accurate reproduction of an impulse signal (which music signal is more akin to), in order of accuracy: Bit-Perfect > Minimum Phase > Standard.

500x1000px-LL-e696da95_Differentfilters_zpsc54e4d84.jpeg

 

Which one would you rather listen to? We do not mind. Because you can choose yourself with the micro iDSD.

 

We have our preference but the customer should always come to their own sonic conclusion.

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Outta This World #1 "Audio has a New Order: the micro iDSD"

 

Octa-Speed DSD512 + 768kHz

 

Over the last few weeks we kept you guessing OTW#1 but along the way, gave some clues:

i. 3 Donuts

ii. Mention of “Damp squid”

iii. Picture of Godzilla and wrestling with Gezora

 

The ANSWER was that the micro iDSD is capable of OCTA-SPEED DSD512 and not only that but also PCM768kHz and 2xDXD (it is mega on all 3 formats)

 

Capable of full DSD512 and 768kHz PCM (2xDXD) directly from the computer to the micro iDSD via USB, natively with NO conversion - we have had to bite our lip as we have been absolutely gagging to tell you but had to keep refraining from letting anything slip.

 

We have probably driven you all rabidly insane guessing OTW#1 but now it is finally out, we hope you are positively salivating as the prospect of enjoying some stonking audio quality that is not a quantum leap but an Octa-Leap!

 

OTW#1: Octa-DSD512/PC768kHz/2xDXD

500x1000px-LL-c78bfe06_LOGOver18_zps72885270.jpeg

 

Background

Computer audio technology is advancing at breakneck speed. AMR/iFi is at the cutting-edge of this. The upcoming micro iDSD propels our market-defining position even further ahead.

 

We have made extensive enquiries and to the best of our knowledge, the micro iDSD will be the very first DAC in the world capable of ALL 3 of the following, native: Octa-Speed DSD512, PCM768kHz and 2xDXD!!! (Up/OverSampling does not count, sorry!)

500x1000px-LL-0d4e0f55_mDSDunderside_zpsc3bd4416.jpeg

 

By comparison, even the most expensive DACs in the world costing upwards of US$50,000, are a little “old hat” as they are several format levels behind only now, attaining:

DSD128 (one or two at DSD 256)

PCM384kHz

 

The iFi micro iDSD feature set means it has blasted light years ahead to bring true high-end technology to the mass market.

 

To summarise the micro iDSD’s Outta This World features:

 

Outta This World #1 Octa-Speed DSD512/PCM768/2xDXD

 

Outta This World #2 Perfect-Match with Headphone Power modes and iEMatch

 

Outta This World #3 Turbo headamp power output of 8v/4000mW

 

The micro iDSD is available in stores mid-July so you are only ~two weeks from having the Micro iDSD in the palm of your hand.

 

 

Explanation

We are all in the pursuit of ever better quality of audio playback. DSD is in resurgence and shows no signs of abating. PCM should cannot be ignored as the library of PCM vs DSD recordings is still overwhelmingly in favour of PCM.

 

For us, we don’t favour one format over the other. We enjoy both and we believe you should do too. The hard part is to source music on each format – life is too short to worry about which format is “better” we’d rather you enjoy both to the highest possible standard.

 

 

How this benefits the listener

Since we have been running this Crowd-Design project, along the way, we hope you have gathered a better sense of why we do not concern ourselves so much with each format, but offer the widest choice possible whilst making a recommendation based upon what we like, but always advising that you find what you like.

 

In this case, by being able to select the correct format for each file type, you have ensured a chain that is

 

DSD recording > DSD playback

500x1000px-LL-c2290a0f_DSDnativepath_zps98229a51.jpeg

Or

 

PCM recording > PCM playback

500x1000px-LL-69c11a90_1-01_zps7a814027.jpeg

 

This matters because we strongly believe that the original cannot be bettered and should be retained end-to-end (i.e. not just on the playback side as we always talk about the whole chain).

 

With this OTW#1, Quad-Speed DSD256 recordings are now making a breakthrough and we have it on good authority that Pyramix and Sonoma which are already on the Quad-Speed DSD256 standard will see a revision in 3Q 2014 to enable their recording systems to handle Octa-SpeedDSD512.

 

This does not include the moves by recording studios to also move to a higher sample rate on the PCM format.

 

What this means for you, the micro iDSD customer is real, hard future-proofing for many years to come. And from day one!

 

For more information on the micro iDSD and others:

Micro – iDSD

 

 

We will also post links to super hi-res music downloads over the coming days. Super hi-res recordings are coming…

 

From all the staff/directors at AMR/iFi, a big THANK YOU for participating in this Crowd-Design project, you have helped make the micro iDSD one helluva "Meaty Monster!"

And more to come…

Last but not least, within the next few days, we shall outline how the upcoming first production run of micro iDSDs will be special “Octa-Adopter” units. There are extra goodies - these will be collector’s units in the years to come.

 

Watch this space!

Edited by Stereo_Electronics

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iFi Audio Micro iDSD Pre-Order @ $649!

 

Yes, you saw it right! Starting today, 4th July, Stereo Electronics is now accepting pre-orders for Micro iDSD.

 

Pre-order batch is extra special with a FREE T-shirt plus a unique "Red Hot Turbo" serial number that comes on each set. We are expecting the stocks to arrive by mid or end of this month.

 

Hurry and be one of the firsts 512-first batch unit owners worldwide and make a pre-order only at Stereo@Plaza Singapura or Stereo@ION Orchard!

MicroiDSDPre-Order_zps61032874.jpg

 

Read up for more info:

iDSD micro Crowd-Design. HiFi Man HE-6 takes on the Meaty Monster! (page 82) - Page 73"]iDSD micro Crowd-Design. Head-Fi

 

Stereo your one stop headphones and earphones store in Singapore"]Micro iDSD. Stereo - The Headphone Concept Store

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micro iDSD: Super Duper 2.2. The iPurifier

500x1000px-LL-0251d150_iPurifier_logo_zps94ac2b99.png

 

Background

This is the last of the Super Duper features so it is fitting that we cover one of the Crowd-Design features you asked for - the iPurifier to be incorporated into the micro iDSD.

 

Well, the micro iDSD features iPurifier technology to tackle issues surrounding USB transmission.

 

Explanation

The USB carries the audio+power signal downstream from the PC.

350x700px-LL-cd058fef_usb_cable_20_construction_zps75b6b5da.jpeg

 

Due to the general implementation of costing-cutting in PC hardware (mass market product), the USB signal coming from the PC is usually low-quality and certainly inadequate for quality USB audio playback.

 

Together with the unwanted EMI/RFI picked up along the way, the USB signal (which is a balanced signal) becomes unbalanced, noisy and exhibits detrimental DC offset.

 

This imperfection can easily be confirmed just by applying an oscilloscope on the USB signal (the oscilloscope needs to have sufficient bandwidth, say 300MHz, otherwise the oscilloscope will be too slow and the issue will not be visible).

 

The iPurifier in the micro iDSD:

Cleans up the data lines

Re-balances the USB signal

Removes the DC offset and

Filters out the EMI/RFI noise.

 

Graphically, like this:

500x1000px-LL-1e345c88_iPurifier_graphs_zps321bdc85.png

 

The iPurifier filter in the iDSD micro forms a lowpass which rejects High Frequency noise. At 1MHz it reduces noise by around 50dB (300 times).

 

The filter is designed to filter both differential and common mode noise, it will also stop noise radiating along the ground line and thus polluting the audio grounds with RF noise.

 

How this benefits the listener

Better inner resolution and better noise floor compared to one without the iPurifier. The iPurifier also renders the USB cable/adapter issue much less of a concern.

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Power Matters

350x700px-LL-2c595057_Turbo_zps733debf1.jpeg

 

Over the last few days, we have been a little quiet. You guys have emailed and PM'd us about the micro iDSD but we have keep mum because we wanted to nail a last few items down before going public.

 

Besides getting the one unit to Japan for the Net Audio photoshoot, we have been fine tuning the power output of the micro iDSD. In turn, we had to modify the software to allow these higher power levels, as our power supplies are controlled by the microprocessor and the software.

 

The thought to just send out the micro iDSD as is, had crossed our mind, but given our OCD for implementing the very best technology, we just had to do that one last thing.

 

Well, below, you will see the revised power output figures as measured on the AP2. We have underlined the most important power changes.

ScreenShot2014-07-16at115221am_zps1c666bcb.png

 

Salient Points

Turbo mode - the continuous power has been uprated from 1000mW to 1,560mW. This increased power means in actual listening, better dynamic grip and bass response is better for the most demanding of headphones*.

Normal mode - continuous power is also up from 500mW to 950mW. Same as Turbo but for medium-efficiency headphones.

Eco mode – minor adjustment for maximum power from 250mW to 500mW, the continuous power of 250mW remains unchanged.

 

We tested using the Hifi Man HE-6 and now, from heavy metal through to jazz tracks, these headphones are even more enjoyable than before and when required, these drivers move some serious air.

 

Regardless, whichever headphone you use with the micro iDSD, it should retain an overall even better control/grip of that headphone, especially during dynamic swings and when the bass goes loooow.

 

Things have not changed much for IEMs (as these are most likely to be used in Eco mode).

 

In the next few days, we will also update you on the battery-side of things as behind-the-scenes, it is quite complex.

 

As a result of this, the worldwide launch date (when it should be in retailers) has been shifted from 15th July > 22nd July.

 

We know you are somewhat eager to get your hands on the micro iDSD - but we think you will find the additional 1-week wait was worth it.

 

Cont'd

iDSD micro Crowd-Design. iDSD Tutorial: MP3>DSD256/512. Get more out of those compressed tunes! (page 93) - Page 86

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Team iFi udates micro iDSD: Those Pesky Bugs!

 

Hi all,

 

The software revisions following the power increase took a couple of days longer than expected to fully-implement.

 

Last week, we crunched through the night, every night, through the weekend and then some. There were some software bugs that needed squashing and they took somewhat longer than expected.

 

Just about everything in the micro iDSD is inter-related so we could not change the hardware without changing the software - for the battery recognition alone, there are a few thousands lines of code.

 

Here is a screenshot of some of that:

500x1000px-LL-a06cbf8a_code_sample_zpse156154e.png

 

This gives you a small insight into how much of a pain it was to debug. Given we write our own code, we were the only ones who could sort it out!

 

The good news is that it has been sorted.

 

The bad news is that this added 3-4 days of delay so now, all retailers should have their units ~Monday 28th July (instead of 22nd July).

 

Cont'd

iDSD micro Crowd-Design. The Meaty Monsters are flying out! (page 95) - Page 90

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SmartPower® Some say, it is so smart it should have a PhD.

 

Ahead of the global launch on 28 July, this article sheds some light on SmartPower® which is the complete battery power management/Smart device recharge functionality of the micro iDSD.

 

How, why and what the battery recharging function does in the upcoming micro iDSD.

350x700px-LL-e2fc1504_SmartPower_zps694dc240.jpeg

 

IMPORTANT INFORMATION:

Upon first receiving your micro iDSD, we strongly recommend that it undergoes a full-24 Hour charge with the unit turned OFF. This gives it the absolute best start and maintenance for many years to come. In addition, after a long period of disuse or after the battery has gone completely flat, please allow a full 24-Hour charge cycle.

 

Also, different USB cables are able to carry different amounts of current. We recommend the USB 3.0 cable (supplied in the micro iDSD) for fastest recharging.

 

Afterwards, you can mostly relax about the battery.

 

 

Background operational information

If the PC goes into normal standby, it is usually possible to set it to keep the USB ports alive. The iDSD micro’s power and battery management system is designed with the maximum “smarts” built-in to look after your battery.

 

The battery we use includes protection circuitry that will self-disconnect in case of overvoltage, excessive load current or low-voltage.

The protection circuitry is self-resetting and even under low-voltage shutdown, the battery can be charged. This way the battery is maximally-protected from conditions that may damage it.

 

This is built-into the battery itself and independent from anything we at iFi do. But we go out of our way to make sure the protection circuitry has a cushy job, it just comes to the office, pours itself a cup of coffee and then puts its feet up on the desk. Normally there is never any work for it...

 

350x700px-LL-84cddbe0_photo3_zpsb13b9abe.jpeg

 

Power-save: when no signal is detected

The iDSD micro likes to guzzle juice, especially in Turbo mode. So, we implemented a power-save mode to cover all eventualities. If there is no signal on either SPDIF or USB input the iDSD will go to sleep after either:

 

After 3 minutes on battery or

After 15 minutes on USB power

 

Only the SPDIF input and the ARM Cortex remain powered if there is no USB (otherwise USB is also powered up) and will be set to the lowest power consumption, in total a few 10 milli-ampere. This maximises play time on battery and on USB power allows charging at the maximum rate while “sleeping” when turned on.

 

 

Works while it sleeps

Even better, while in battery mode with a USB source attached the iDSD micro will attempt to detect if it is attached to a charger or computer or a smart device. If attached to PC or charger even in battery mode, the iDSD micro will charge when in sleep mode, it will switch back to 100% battery power when playback resumes.

 

At the lowest power-save sleep rate of discharge a full battery can last 4 days before the iDSD micro will go into full shutdown, as the battery charge becomes too low. Even at that point there is enough charge remaining to avoid engaging the battery’s own protection circuitry for several weeks.

 

 

Measures to maximise battery life

In addition, we have implemented the maximum possible measures to extend battery life, including different charging end voltages for "always on" and "cycle" use. As long as the iDSD micro is switched on, the battery is charged to a lower voltage, this makes the battery’s lifespan essentially the same as the shelf-life, as it is never stressed. This limits battery capacity to around 80%, which is still plenty, unless you are wearing your K1000's out on the subway and you need to run Turbo mode with the volume maxed out.

If charging with the iDSD micro switched off, the battery is charged to 100%, so if you do and switch to Economy mode you should have juice enough for LAX (Los Angeles) > NRT (Narita) or ICN (Incheon) non-stop listening all the time including a couple of hours in the waiting lounge...

 

To be cont'd.

 

iDSD micro Crowd-Designed. Phase 2: What speakers did you use to develop the micro iDSD? (page 101) - Page 98

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