iDAC2. Calling 5 Head-Fi'ers. A litte surprise. (page 37) | Headphone Reviews and Discussion - Head-Fi.org

iFi audio · Feb 12, 2015 at 12:15 PM

This is mid-point between the nano iDSD and the micro iDSD.

This replaces the original iDAC.

Some initial specs :

- Burr-Brown chipset (same as nano iDSD and micro iDSD)

- True Native on DSD256 and PCM384khz

- Bit-Perfect, Minimum Phase and Standard filter settings

- USB 'B' input with Jitterless Lite

- SPDIF output

- 350mW headphone amplifier

The iDAC2 is available for audition at the upcoming Bristol Show with LCD-X, LCD-2 and HE-6. All in the iFi "Big Rig".

See you there!

iDAC2 album by Sound Liasons - Free PCM/DSD (page 21)
http://www.head-fi.org/t/754820/idac2-launching-with-a-bang-competition-with-mega-goodies-gotta-be-in-it-to-win-it-see-page-4-for-details/300#post_11749432

#4 and #5 Winners are

http://www.head-fi.org/t/754820/idac2-is-landed-4-and-5-winners-are-page-27-also-free-dsd-pcm-album-see-page-21/390#post_11781614

#2 and #3 Winners are (post 418)
http://www.head-fi.org/t/754820/idac2-is-out-4-and-5-winners-are-page-27-also-free-dsd-pcm-album-see-page-21/405#post_11784027

#1 Winners is
http://www.head-fi.org/t/754820/idac2-is-out-2-and-3-winners-are-page-28-also-free-dsd-pcm-album-see-page-21/435#post_11790916

iFi audio · Feb 14, 2015 at 12:14 PM

This is a summary of the current iFi family of digital-to-analogue converters.

In descending order, think of them as BMW 5 series, 3 series and 1 series.

Model

Chipset

no of DACs

Native

DSD

Native PCM

Filters

Zerojitter Lite

SPDIF

iPurifer Lite

Battery

Headphone
Amplfiier

XBass®

3D Holographic®

micro iDSD

Burr-Brown (True Native)

2

Up to Octa-DSD512

Up to 768kHz

Bit-Perfect/
Min Phase/
Standard

Yes

In/Out

Yes

Up to 4,000mW

Yes

For Headphones
and Speakers

micro iDAC2

Burr-Brown (True Native)

1

Up to Quad-DSD256

Up to 384kHz

Bit-Perfect/
Min Phase/
Standard

Yes

Out

No

350mW

No

nano iDSD

Burr-Brown (True Native)

1

Up to Quad-DSD256

Up to 384kHz

Min Phase/
Standard

Yes

Out

No

Yes

150mW

No

iFi audio · Mar 13, 2015 at 9:06 AM

Looking under the lid of the iDAC2

Close-up of the Silmic Caps (part 1)

At the heart of the iDAC2 is a brand spanking new, ground-up analogue stage, designed to give optimal line output from the Burr-Brown DSD/DXD native DAC Chip used. To support this analogue stage two special audio grade Elna Japan Silmic II (the highest available grade and likely the best audio grade electrolytic capacitor money can buy) are fitted. Heck, these are used in the uber AMR machines.

The Analogue stage also uses a discrete, Class A buffer that combines a N-Channel J-Fet and a PNP bi-polar transistor that allows this buffer to handle even 600 Ohm loads. While in the end not applied in the upcoming Pro range, this buffer was originally designed and tested for inclusion in the Pro range, before it was decided that something more radical would be used in the Pro line.

All this analogue circuitry is directly below the two Silmic capacitors, this "3D" Arrangement of circuitry making sure the capacitors providing the "backup power" for the Class A buffer are as close as possible to the circuit they supply.

Next time, Part 2.

Mr Creosote · Mar 13, 2015 at 4:36 PM

Just noticed this.Looks very interesting I wonder what the price will be?Should be very reasonable if it is between the iDSD nano and iDSD micro.
Looks like some nice parts inside.

HPiper · Mar 13, 2015 at 5:54 PM

When is this going to become available to the general public? Any idea of the price, I would assume it is going to be around $350 being as how the Nano is about 190 and the micro is 500. I was about to get a DSD Micro but I may wait now and get one of these instead.

iFi audio · Mar 16, 2015 at 2:38 PM

hpiper said:
When is this going to become available to the general public? Any idea of the price, I would assume it is going to be around $350 being as how the Nano is about 190 and the micro is 500. I was about to get a DSD Micro but I may wait now and get one of these instead.

Hi,

In about 4 weeeks' time.

We are finalising the packaging design and marketing materials.

Otherwise, the iDAC2 is on the launch pad.

iFi audio · Mar 17, 2015 at 9:02 AM

Looking under the lid of the iDAC2

Close-up of the Topside (part 2)

Topside PCB comments:

Noteworthy, past the two Elna Silmic Power Supply capacitors that decouple the power for the analogue stage and Class A Line Output Buffer is the large number of 470uF low impedance electrolytic capacitors that decouple the power supplies for other circuit parts.

1. The four capacitors on the far right (#1 at the far end, near the analogue volume potentiometer) are responsible for backing up the power for the headphone Amplifier two each per channel, the headphone Amplifier is dual-mono, with two separate headphone amplifiers. Having big power supply capacitance only a few mm from the Amp means it can deliver transients easily, at full power.

2. At the lower edge, centre is the DAC section (underlined) and its power supply including our new and rather unique shunt noise filter (#2 green arrow) which cleans the USB Power for the DAC. For the DAC there is a critical pin called "reference." We always pay much attention to this pin, however the iDAC2 benefits already from trickle-down from the upcoming Pro-range where we utilised a high-grade Panasonic Japan made Film Capacitor for surface-mounting, which combined with a smaller value C0G capacitor provides the "cleanest" reference pin voltage yet. On the AP2, it measures pretty darn nice.

3. The left part of the PCB is the whole digital engine with the digital power supplies, back again with a brace of 470uF low impedance capacitors, the Audio Clocks (which have a dedicated low-noise linear regulator) and the switch to select the digital filters.

Next time, PCB underside comments.

KT66 · Mar 17, 2015 at 1:57 PM

I first met you at a Vintage Audio Jumble in Tonbridge what seems a long time ago now!
I was very impressed, but the "3d" button put me off.
I see this doesn't have that button, is it still on your other products?

iFi audio · Mar 18, 2015 at 5:06 AM

kt66 said:
I first met you at a Vintage Audio Jumble in Tonbridge what seems a long time ago now!
I was very impressed, but the "3d" button put me off.
I see this doesn't have that button, is it still on your other products?

Hi,

Yes - nice mini show is the AudioJumble.

The 3D Holographic for Headphones is an on/off switch.

Plus it is Analogue Signal Processing, not Digital Signal Processing - so it is quite different to other implementations that have garned not so good press.

Further, the iDAC2 does not have it.

The micro iDSD has it - along with nano/micro iCAN (for Headphones), iTUBE (for speakers).

Cheers.

rickyleelee · Mar 19, 2015 at 7:12 AM

ifi audio said:
This is mid-point between the nano iDSD and the micro iDSD.

This replaces the original iDAC.

Some initial specs :

- Burr-Brown chipset (same as nano iDSD and micro iDSD)

- True Native on DSD256 and PCM384khz

- Bit-Perfect, Minimum Phase and Standard filter settings

- USB 'B' input with Jitterless Lite

- SPDIF output

- 350mW headphone amplifier

The iDAC2 is available for audition at the upcoming Bristol Show with LCD-X, LCD-2 and HE-6. All in the iFi "Big Rig".

See you there!

Me wants the under side

iFi audio · Mar 20, 2015 at 1:04 PM

Looking under the lid of the iDAC2

Close-up of the Underside (part 3)

Here we can see the analogue stage that occupies the centre of the PCB. We can see the J-Fet input "Soundplus®" Op-Amp from Burr-Brown (by TI) which is actually a Quad type.
The second pair of Op-Amps inside the case are used as DC servo, to eliminate any need for coupling capacitors.

So yes, the signal path is DC coupled from the DAC all the way to the RCA and Headphone jacks!

As a DC servo not only handles the DC offset in the circuit, but must remove all the signal before feeding the correction voltage into the Audio Path any distortion here will cause problems. The common solution is the use of inexpensive and poor quality Op-Amps for the DC Servo, leading to unanticipated sonic compromises.

As can be seen, passive components for the analogue stage are also at the highest level of Quality, with MELF resistors and C0G capacitors for all critical sections (including the power supply).

C0G Capacitors

MELF Resistors

Leftmost is the new dual-mono headphone amplifier, with extensive power supply decoupling for lowest noise, including C0G Capacitors.

Again, MELF resistors are used for the audio functions.

As you can gather by now, we don’t use inexpensive parts and to give you some idea of the lengths we go to, we will upload some internal pics of the soon to be launched 777 Signature Edition as they are also used there too.

earfonia · Mar 27, 2015 at 12:12 AM

ifi audio said:
This is a summary of the current iFi family of digital-to-analogue converters.

In descending order, thing of them as BMW 5 series, 3 series and 1 series.

Model
Chipset
no of DACs

Native

DSD

Native PCM
Filters
Zerojitter Lite
SPDIF
iPurifer Lite
Battery
Headphone
Amplfiier
XBass®
3D Holographic®

micro iDSD
Burr-Brown (True Native)
2
Up to Octa-DSD512
Up to 768kHz
Bit-Perfect/
Min Phase/
Standard
Yes
In/Out
Yes
Yes
Up to 4,000mW
Yes
For Headphones
and Speakers

micro iDAC2
Burr-Brown (True Native)
1
Up to Quad-DSD256
Up to 386kHz
Bit-Perfect/
Min Phase/
Standard
Yes
Out
No
No
350mW
No
No

nano iDSD
Burr-Brown (True Native)
1
Up to Quad-DSD256
Up to 386kHz
Min Phase/
Standard
Yes
Out
No
Yes
150mW
No
No

Thanks for the comprehensive information!

I would like to ask about the meaning of the 'True Native' label for the Burr-Brown DAC. Probably I have wrong understanding, please correct me if I'm wrong. My understanding is, unless the DAC is the ladder R2R DAC, these days we actually don't have new native PCM DAC chip anymore, as the PCM data is converted to bitstream by Delta-Sigma (or Sigma-Delta) modulator, before converted to analog by a low pass filter. So the DAC chip is true native for DSD, but not true native for PCM.

I'm not against or pro to any of the conversion technique. I'm just trying to understand what 'True Native' means.

Unless ifi is using 2 type of DAC chip, R2R for PCM, and Delta-Sigma for DSD. Kindly please enlighten me, Thanks!

Beside that, I would like to know the consideration of placing the RCA output at the front panel, and placing the On/Off power switch at the back. Why not the other way around. Tx!

ClieOS · Mar 27, 2015 at 2:57 AM

earfonia said:
Thanks for the comprehensive information!

I would like to ask about the meaning of the 'True Native' label for the Burr-Brown DAC. Probably I have wrong understanding, please correct me if I'm wrong. My understanding is, unless the DAC is the ladder R2R DAC, these days we actually don't have new native PCM DAC chip anymore, as the PCM data is converted to bitstream by Delta-Sigma (or Sigma-Delta) modulator, before converted to analog by a low pass filter. So the DAC chip is true native for DSD, but not true native for PCM.

I'm not against or pro to any of the conversion technique. I'm just trying to understand what 'True Native' means.

Unless ifi is using 2 type of DAC chip, R2R for PCM, and Delta-Sigma for DSD. Kindly please enlighten me, Thanks!

Beside that, I would like to know the consideration of placing the RCA output at the front panel, and placing the On/Off power switch at the back. Why not the other way around. Tx!

The same question has been answered by Thortsen Loesch in this article: http://www.audiostream.com/content/qa-thorsten-loesch-amrifi

More detailed explanation is in the article, but here is what you are probably looking for:

Ideally we play PCM back as PCM, with a true Multi-bit DAC (no matter what the original ADC source is – we invariably save one stage of manipulation and losses). And we play back DSD as pure Delta Sigma, with no manipulation in the digital domain at all (no matter what the original ADC source is – we invariably save one stage of manipulation and losses). This is what we call “native” playback. DSD remains DSD and is converted directly to analogue. PCM remains PCM and is converted directly to analogue.

In the iDSD nano (and the whole upcoming iDSD range) we go to great length to provide that. Finding a readily available DAC chip that treats both DSD and PCM fairly was a challenge. Manufacturers generally are quite mum about what goes on inside their chipsets, so often you have to actually test the part in detail to figure out what is really going on.

The DAC chip we use in the iDSD nano offers a rather unusual way to handle things. It uses a 6-bit true Multi-bit DAC for the upper 6-bits of PCM Audio and delivers the warmth and slam Burr Brown Multi-bit DAC’s are so famous for. Any bits below this are converted with a low order 256 speed Delta Sigma modulator (in effect DSD256), giving PCM playback the smoothness Delta Sigma DAC’s and DSD are famed for.

When playing DSD the same Delta Sigma Modulator is used as directly to convert the DSD bitstream to analog. Of course, there is no digital filtering available for DSD and no digital volume control, so we have to add these features in the analogue domain, where they arguably should belong.

Note: the same chip is used for both iDSD nano, micro as well as the upcoming iDAC 2.

earfonia · Mar 27, 2015 at 3:22 AM

clieos said:
The same question has been answered by Thortsen Loesch in this article: http://www.audiostream.com/content/qa-thorsten-loesch-amrifi

More detailed explanation is in the article, but here is what you are probably looking for:
Note: the same chip is used for both iDSD nano, micro as well as the upcoming iDAC 2.

Thanks you very much !
So that what it means by 'True Native'

iFi audio · Mar 27, 2015 at 4:50 AM

earfonia said:
Thanks for the comprehensive information!

I would like to ask about the meaning of the 'True Native' label for the Burr-Brown DAC. Probably I have wrong understanding, please correct me if I'm wrong. My understanding is, unless the DAC is the ladder R2R DAC, these days we actually don't have new native PCM DAC chip anymore, as the PCM data is converted to bitstream by Delta-Sigma (or Sigma-Delta) modulator, before converted to analog by a low pass filter. So the DAC chip is true native for DSD, but not true native for PCM.

I'm not against or pro to any of the conversion technique. I'm just trying to understand what 'True Native' means.

Unless ifi is using 2 type of DAC chip, R2R for PCM, and Delta-Sigma for DSD. Kindly please enlighten me, Thanks!

Beside that, I would like to know the consideration of placing the RCA output at the front panel, and placing the On/Off power switch at the back. Why not the other way around. Tx!

Hi,

Thanks.

True Native simply means there is not conversion inside the chipset. So DSD stays DSD and PCM stays PCM - throughout. Very few chipsets do this. You have to look 'behind the curtain' so to speak.

As for the detailed technical aspects, there is way too much information but here is where we laid it all out:

http://www.audiostream.com/content/qa-thorsten-loesch-amrifi

What CLIEos has pointed out is correct.

No Standby switch because here in the UK, being part of the EU, the environmental regulations have gone crazy.

From 1st Jan 2013, it was mandatory that Standby meant power consumption of <0.5W (not a typo).

Any electrical product that does not conform faces a hefty Euro5,000 fine.

AMR/iFi in order to conform, we do not have a switch as this ensures our products have and will always conform. Totally On or totally Off.

Hope this sheds more light.

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