iFi Audio Pro iDSD discussion thread
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flyte3333

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The circuit path is entirely direct coupled, Class A (except when driving very low impedance headphones to very high power levels).
Hi iFi, what is the circuit path with very low impedance headphones driven to high levels?

Cheers
 
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Probably it goes into Class A/B like many other amps.
 
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Would really like some info on the filters, the manual says

'Bit-Perfect' No digital filtering is applied, one tap
'Bit-Perfect+' No digital filtering is applied, one tap, SINC roll-off is corrected
'Gibbs Transient Optimised' 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

Ringing? taps? what? ;/ What does it all mean in layman terms? Which should I set it to for what reason? hahaha
 
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There's no simple way to explain it all. Digital-to-Analog conversion is complex. I'll give you a very short summary. If you don't understand the basics of digital audio, you'll need to learn how regular PCM audio encodes analog waveforms at the very least.

A DAC has to re-construct the analog waveform using a number of samples taken of the waveform by the original Analog-to-Digital Converter (ADC). The samples are, more or less to a degree inaccurate as, as it is limited by the bit and sample rates, eg: 16/44.1 for "CD Quality". The DAC has to interpolate samples in between those taken to (reasonably) accurately reconstruct the analog signal. This is called "oversampling" (or "upsampling" sometimes). If you don't do this (ie: use the Pro iDSD's Bit-Perfect, or "Non-OverSampling"/NOS mode) you get a form of distortion that results in a loss of clarity. That is, how you perceive the soundstage will be smaller, and instruments will be less focussed.

Over the last couple of decades, there have been all sorts of arguments about how best to create a digital filter. Those arguments have included a focus on the "ringing" that you see around an impulse response sent to a DAC, even though impulse responses don't exist in music (they contain frequencies outside the sample rate, but people got hung up on this for a long while). That's what the GTO and Apodising filters are. Now here is where it gets funky. Some people don't like the sound with the various filters (massive quagmire, don't ask) and so prefer Bit Perfect (NOS) DACs. The particular DACs in the iDSD are sometimes used by people to build DIY non-oversampling DACs and are particularly good if NOS DACs are your thing.

However, with more recent advancements in the amount of computing power that can be put inside a DAC, it is possible to create much more accurate filters than are included with regular DAC (or filter) chips. That leaves us with the most technically accurate filter, the Transient Aligned, that uses the greatest amount of interpolation to most precisely reproduce the original signal.

Alternatively, you can set the Pro iDSD to re-sample everything to DSD512 or DSD1024. DSD is a 1-bit, extremely high-frequency sampling method. It has its own technical imperfections, but can produce results that sound very spacious, but less precise, depending on the DAC.

So what should you set? Whatever you like. There's no right answer.
 
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post-14429815
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Hunki Chunki

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That was roughly what I thought it will have to be. I guess I will have to try them all and just leave it at something when its all said and done.

Thanks for the write up! That will give me something to start with haha!
 
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There's no simple way to explain it all. Digital-to-Analog conversion is complex. I'll give you a very short summary. If you don't understand the basics of digital audio, you'll need to learn how regular PCM audio encodes analog waveforms at the very least.

A DAC has to re-construct the analog waveform using a number of samples taken of the waveform by the original Analog-to-Digital Converter (ADC). The samples are, more or less to a degree inaccurate as, as it is limited by the bit and sample rates, eg: 16/44.1 for "CD Quality". The DAC has to interpolate samples in between those taken to (reasonably) accurately reconstruct the analog signal. This is called "oversampling" (or "upsampling" sometimes). If you don't do this (ie: use the Pro iDSD's Bit-Perfect, or "Non-OverSampling"/NOS mode) you get a form of distortion that results in a loss of clarity. That is, how you perceive the soundstage will be smaller, and instruments will be less focussed.

Over the last couple of decades, there have been all sorts of arguments about how best to create a digital filter. Those arguments have included a focus on the "ringing" that you see around an impulse response sent to a DAC, even though impulse responses don't exist in music (they contain frequencies outside the sample rate, but people got hung up on this for a long while). That's what the GTO and Apodising filters are. Now here is where it gets funky. Some people don't like the sound with the various filters (massive quagmire, don't ask) and so prefer Bit Perfect (NOS) DACs. The particular DACs in the iDSD are sometimes used by people to build DIY non-oversampling DACs and are particularly good if NOS DACs are your thing.

However, with more recent advancements in the amount of computing power that can be put inside a DAC, it is possible to create much more accurate filters than are included with regular DAC (or filter) chips. That leaves us with the most technically accurate filter, the Transient Aligned, that uses the greatest amount of interpolation to most precisely reproduce the original signal.

Alternatively, you can set the Pro iDSD to re-sample everything to DSD512 or DSD1024. DSD is a 1-bit, extremely high-frequency sampling method. It has its own technical imperfections, but can produce results that sound very spacious, but less precise, depending on the DAC.

So what should you set? Whatever you like. There's no right answer.
hello, thank you for your comments, and for your analysis on the dacs in general, from what I understood, either one is on the precision and less musicality, or conversely,
have you been able to compare the iDSD pro dacs costing much more expensive, this to know the real possibilities of the iDSD pro, it is easy to give qualities of analysis, silence, configuration, but most of the time these comparisons are made with dacs of the same price level or even lower, it is by making more in-depth comparisons that we can better appreciate the real performance of the iDSD pro, I think some specialized journalists have to think about it, thank you
 
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hello, thank you for your comments, and for your analysis on the dacs in general, from what I understood, either one is on the precision and less musicality, or conversely,
have you been able to compare the iDSD pro dacs costing much more expensive, this to know the real possibilities of the iDSD pro, it is easy to give qualities of analysis, silence, configuration, but most of the time these comparisons are made with dacs of the same price level or even lower, it is by making more in-depth comparisons that we can better appreciate the real performance of the iDSD pro, I think some specialized journalists have to think about it, thank you
Currawong has a video review of the unit here ->

 
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iFi audio

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Folks...

IFA 2018
...it's almost here!



  • When?
The 31st Aug - 5 Sept 2018!
  • The place?
Berlin!
  • Where exactly?
Hall 1.2, stand 206, WOD Audio (iFi's German distributor)

You'll have a chance to preview our EISA award winner - xDSD! Our two lovely girls - Victoria and Sarah - will be there supported by Thorsten Loesch himself.

If you'll attend, please visit us!
 
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Also folks, AMR will be demoing two machines in the Colorado Audio Society Hospitality Suite at RMAF. Room 6007.




Yup, we're giving away Fast Blow fuses for Magnepan speakers! 2.5A for Magnepan 3.6/3.7 and 4A for other Magnepan machines.
 
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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.
Hi @iFi audio
Is it correct that each of all 5 PCM filters can be applied if PCM to DSD conversation is chosen? For example a cd quality source can be shaped using Transient Aligned filter and then converted to DSD 1024?
Question 2: will this apply in the same way to unfolded MQA files (once this becomes available)? I.e. MQA fully unfolded, then Transient Aligned filtering, then DSD conversion..
Question 3: when will MQA conversation come to Pro iDSD ? Or is there a technical issue to keep this promise?

Thanks,
Özgür
 
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Promising review by Darko:
https://darko.audio/2018/10/off-the-dial-flexibility-and-value-with-ifis-pro-idsd-dac/

It seems Darko heard sound being shaped by Transient Aligned filter when converting PCM to DSD. at least this is his favourite setting..

I own the Pro iDSD for few days now. I’m between “awesome sound” and “this is too harsh”. There are so many combinations (45 to be precise) of sound shaping possible that a week will not be enough to find perfect. I’m very confident that one or two of the combinations will be perfect. The challenge is that “with great power comes great responsibility” and I’m not sure if choosing the right setting for each different track / recording / mood will spoil it in the end. Sometimes I think “life was so simple with a mojo and an iPhone”.. just fun. Now with McIntosh MHA100, LCD-4, Special cables, and 45 options on a super dac, it seems a little fun spoiling. But hey, I could go back anytime and choose not to :) so no complaints, just reflection ..
 
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Two more points:
1. The device is on a slippery mat as bottom. Very annoying as you always have to press it down when operating buttons / switches, otherwise it will move around.. I ordered an “Anti-slip Car Dash Sticky Pad” from amazon and will check if this improves handling .. should not really have to rely on a £5.99 Amazon mat to stop the £2k device from slipping around during intended operation and use.

2. The SS/Tube/Tube+ switch is so stiff that you have to hold the dac with the other hand while switching, and always have to check whether you moved two clicks or one. If anyone has found a way around this let me know please, as I would rather not try to loosen the switch with houndreds of “powered off back and forth movements” ..

Cheers,
Ozgur
 
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Hi @iFi audio
Is it correct that each of all 5 PCM filters can be applied if PCM to DSD conversation is chosen? For example a cd quality source can be shaped using Transient Aligned filter and then converted to DSD 1024?
Question 2: will this apply in the same way to unfolded MQA files (once this becomes available)? I.e. MQA fully unfolded, then Transient Aligned filtering, then DSD conversion..
Question 3: when will MQA conversation come to Pro iDSD ? Or is there a technical issue to keep this promise?

Thanks,
Özgür
1. DSD Remaster mode works with filters, therefore yes.
2. We'll explain how MQA interacts with filters once this functionality is added.
3. We're working on this and are almost done.
 
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Update: the mat works perfect. No more slipping.

Update 2: DSD1024, TA filter, tube+ setting in my setup is just AWESOME. Breathtaking. I have to add one more complaint to my negative comments above: this thing is so seductive in sound that it needs a warning sticker for addiction risk. Really. Thanks ifi!
 
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Update: the mat works perfect. No more slipping.

Update 2: DSD1024, TA filter, tube+ setting in my setup is just AWESOME. Breathtaking. I have to add one more complaint to my negative comments above: this thing is so seductive in sound that it needs a warning sticker for addiction risk. Really. Thanks ifi!
You're welcome, enjoy!
 
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