New launch - SPDIF iPurifier

[AMR/iFi audio]

@AMR/iFi audio

 

I'm considering SPDIF iPurifier for my current setup. I take Toslink data directly from the motherboard (Gigabyte, z170 based). it connects to an Onkyo 818 AVR Toslink port (Onkyo mainly used as the pre/pro). Onkyo mentions PLL jitter cleaning circuit is already included.

My sources are relatively clean but the audio signal directly coming from the motherboard makes me a bit nervous given so much stuff going on there.

 

Any pointers? Thanks

 

We wouldn't worry too much about the Onkyo AVR. One would need to know precisely what sort of PLL said machine incorporates. All S/PDIF receivers have PLL's and will suppress some jitter, but the problem is that just few do anything in the audio range.PC motherboard SPDIF outputs are usually of quite poor quality. While a iPurifier SPDIF could help here, a better choice may be an external USB to S/PDIF Converter.

[AMR/iFi audio]

We have something special for you today. Lots of things have been said about jitter, and here's our take on the case.

 

 

SPDIF iPurifer^®: Jitter Performance Test Results - Part 1/2

 

Background

 

To show what the SPDIF iPurifier® can do and how it can improve DACs from the inexpensive through to the very expensive, we used the ‘Jitter Generation’ function of the Audio Precision 2 test system to create a ‘J-Test Signal’ (the industry standard for testing and widely used by magazines, including Stereophile, USA).

 

 

The Audio Precision 2 artificially creates a specific, known amount of jitter and then measures how much it is reduced by the SPDIF iPurifier®. Hence it is quite quantifiable AND informative as a measurement tool.

 

The Methodology

 

Audio Precision 2 (AP2) generates a signal with 64,130pS of jitter (measured via loopback into AP2) using a square wave waveform at 250Hz. The specific settings are simply chosen to create a gross amount of easily visible jitter. The test results are scaled to be comparable with those by Stereophile (USA).

 

DACs Tested

 

The majority of DACs (>80%) in the market use either AKM or Cirrus Logic SPDIF receiver chips, hence one DAC using each of these was selected.

The DACs tested are listed below:

 

• DAC 1: AKM based, AK4113 Receiver & AK4490 DAC Chip, RRP US$400
• DAC 2: CS based, CS8416 Receiver & CS4398 DAC Chip, RRP US$500
• DAC 3: BB/TC based, TC Audio DICE Chip as Receiver & PCM1792 DAC Chip, RRP US$5,000

 

The last DAC was included because of two reasons; very high asking price, which indicates its high-end shelf affiliation, and its SPDIF inputs’ specific ‘anti-jitter’ circuitry. It was interesting to see how well it’d work next to DACs with ‘vanilla’ input circuitry.

 

Stay tuned, there's more!

 

 

 

 

 

 

[AMR/iFi audio]

SPDIF iPurifer^®: Jitter Performance Test Results - Part 2/2

DAC 1 - AK4113/AK4490

 

 

DAC 1 - AK4113 & AK4490 - high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz & 64,130pS of 250Hz Squarewave Jitter added; 24-bit data sourced from AP2. Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz. Red trace without SPDIF iPurifier®, Blue trace with SPDIF iPurifier®

 

Without the SPDIF iPurifier® we can see that practically all of the jitter (64,130pS) simply ‘rides through’ causing gross distortion, which actually has the worst peaks past the -70dB upper limit of our graph. It should be noted that here aforementioned -70dB figure is equivalent to less than 12-Bit actual resolution.

 

 

Adding the SPDIF iPurifier® completely eliminates all distortion products relating to the 250Hz jitter frequency and the low-level 229Hz tone in the digital signal, though some low-level sidebands at what appears to be multiples of the mains frequency (50Hz) remain – these are likely caused by noise pickup from the internal mains transformer of the DAC itself (those are outside the remit that SPDIF iPurifier® can cure as they are picked up AFTER the SPDIF iPurifier®).

 

Summary: SPDIF iPurifier® eliminated all 64,130pS of the source jitter.

Jitter Performance Score:

 

• BEFORE: 0 out of 10;
• AFTER: 9 out of 10 (some 50Hz jitter from the power transformer remained).

 

DAC 2 – CS8416/CS4398

 

 

DAC 2 – CS8416 & CS4398 - high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz & 64,130pS of 250Hz Squarewave Jitter added; 24-bit data sourced from AP2. Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz. Red trace without iFi iPurifier® SPDIF, Blue trace with iFi iPurifier® SPDIF

 

The picture without the SPDIF iPurifier® parallels DAC 1 but the results are even worse. Practically all of the jitter (64,130pS) simply ‘rides through’ causing gross distortion which actually has the worst peaks past the -70dB upper limit of our graph. Further, there is a lot of added low level ‘noise alike’ or a-harmonic jitter below -115dB. Not that it matters much, given the gross amounts of jitter passing through. Again, the aforementioned -70dB figure is equivalent to less than 12-Bit actual resolution.

 

Adding the SPDIF iPurifier® completely eliminates all distortion products relating to the 250Hz jitter frequency and most of the low level 229Hz tone in the digital signal. Some low level sidebands at what appears to be multiples of the mains frequency (50Hz) remain. These are likely caused by noise pickup from the internal main transformer of the DAC itself and it can be seen a few distortion spikes related to the 229Hz signal poking up just above the noise.

 

Summary: SPDIF iPurifier® eliminated all 64,130pS of the source jitter.

Jitter Performance Score:

 

• BEFORE: 0 out of 10;
• AFTER: 9 out of 10 (some 50Hz jitter from the power transformer remained).

 

DAC 3 TC-DICE/PCM1792

 

 

DAC 4 – TC-DICE & PCM1792 - high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz & 45,250ps (w/o iP SPD) & 64,130pS (with iP SPD) of 250Hz Squarewave Jitter added; 24-bit data sourced from AP2. Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz. Red trace without iFi iPurifier® SPDIF, Blue trace with iFi iPurifier® SPDIF

 

The DAC completely failed to lock onto our 64,130pS jitter signal and would only lock do so with the SPDIF iPurifier® in the chain.

 

Lowering the jitter added value to 45,250pS allowed the DAC to lock by itself. Once properly locked, this DAC shows what can be achieved if 10 times or more the money of any of the above DACs is spent primarily on precision engineering and not on fancy casework. In effect, this DAC ‘eats’ all the jitter regardless if the SPDIF iPurifier® is used or not.

 

Summary: SPDIF iPurifer® improved the system by increasing the ‘locking range’ of the DAC 4 by ~40% (from 45,250ps to 64,130ps of jitter).

Jitter Performance Score:

 

• BEFORE: 8 out of 10 (couldn’t lock onto the source signal);
• AFTER: (a ‘strictly’) 10 out of 10.

 

Conclusion

 

• The SPDIF iPurifier® can dramatically reduce jitter in the systems (around a thousand times in the cases observed) equipped with DACs based on a ‘text-book’ SPDIF digital receiver design. Yet differences between SPDIF receiver architectures remain observable and so will are sonic differences.

• SPDIF iPurifier® will also improve the sound by providing galvanic isolation to the system.

• SPDIF iPurifier® will also improve the ‘locking range’ of the DACs with anti-jitter.

• SPDIF iPurifier® cannot cure jitter noise if the noise is created AFTER the SPDIF iPurifier®, e.g.: 50Hz power transformer noise pick up by the DAC.

 

Wherever generic, PLL-based SPDIF receivers are used (regardless of a DAC’s price), the potential benefit of the SPDIF iPurifier® is quite tremendous; the worse a source is and the better the DAC quality, the greater outcome from having the SPDIF iPurifier® in the chain.

 

The SPDIF iPurifier® will upgrade the SPDIF input of all DACs regardless of these machines’ price; from entry to an ultra high-end level of performance. The SPDIF section is no longer the ‘weak link in the chain.’

 

[MicJames]

Fascinating results. Thank you for posting.

 

In another thread (perhaps another forum, even) someone from ifi said that the spdif ipurifier would be redundant when used to feed a DAC that employs a PPL for jitter suppression. These results show otherwise, do they not?

 

The author of that post also stated that the ipurifier would be benificial when used with a DAC that employs ASRC for jitter suppression. Could you elaborate on why that is? It does jibe with what I've read about jitter becoming "embedded" in the data with ASRC, but have never quite understood how that works.

 

Thanks for all the info!

[MicJames]

I was mistaken--the post I was referring to is earlier in THIS thread, and states that DACs employing a SECOND ppl after the receiver chip will not benifit from the spdif ipurifier. I gather, then, that the 1st two DACs tested above do not employ that second PPL?

[AMR/iFi audio]

I was mistaken--the post I was referring to is earlier in THIS thread, and states that DACs employing a SECOND ppl after the receiver chip will not benifit from the spdif ipurifier. I gather, then, that the 1st two DACs tested above do not employ that second PPL?

 

Dang, someone had their three shredded wheat today!

 

 

This is correct. The first two DAC's are essentially copies of the IC Datasheet application circuit.

 

Using a secondary PLL or other effective, Bit-Perfect means of eliminating jitter is very rare, > 95% of DAC's, regardless of selling price, simply use a generic Receiver Circuit.

 

Most commonly used to ‘reduce jitter’ are ASRC systems, either as dedicated separate IC's, embedded in the programmes within FPGA's or DSP's or embedded in actual DAC IC's (like ESS).

 

The problem with ASRC is that the incoming data will have significant time-domain variation (jitter) so the ASRC needs to calculate new samples for the output which has a fixed clock. This is done by first applying a digital filter and oversampling by a high factor and then down-sampling again to the output frequency.

 

Well, actually this is what SHOULD be done. With multi-GHz 64Bit CPU's and DSP's the actual re-sampled digital audio would be quite possibly a very close match to the original signal but at a different sample rate.

 

Usually ASRC does not use actual detailed calculation of the results (this takes a LOT of calculation power) but uses ‘lookup tables’ for calculations to increase speed of calculation.

 

But such tables have limited precision in both time- and amplitude domain. So now with jitter the ASRC will flip between lookup tables in sync with the jitter frequency and of course with limited precision lookup, errors will happen that are specific to each lookup table and they are now happening in sync with the jitter. So timing jitter has been removed, but the jitter is re-encoded in the output data through these errors.

 

As the results of the iPurifier SPDIF show, timing errors in the otherwise unaltered data CAN be removed effectively using suitable means. Once data corrupt it cannot be ‘uncorrupted.’

 

Hence at AMR/iFi we generally avoid specifically ASRC and if we can even digital filters and prefer to solve problems at their root.

 

This image illustrates very well how ASRC actually works. This shows well where things can go off track...

 

Source: http://www.patentsencyclopedia.com/img/20120066280_02.png

[Topspin]

Would there be any benefit to placing the SPDIF iPurifier between my audiophilleo2 and my Benchmark DAC3? The AP2 claims 2.6ps of jitter, would this product reduce that number further prior to feeding the DAC?

[MicJames]

Wow, thanks for the detailed explanation. That makes sense (in a general way, as I'm unfamiliar with details of digital audio processing), and also corresponds with what I found in a very limited experiment yesterday. I purchased an spdif iPurifier, and much prefer the sound I hear from it feeding a Lampizator L4/G4 than I do from the stand-alone ASCR jitter-reducer that I already owned feeding the same DAC.

 

The experiment I ran was placing the two jitter reducers in a daisy-chain to see if the ASCR up-sampling from 44.1khz to 96khz sounded better through the iPurifier into the DAC than simply redbook resolution through the iPurifier alone. What I think I've discovered so far (more listening tonight and over the weekend in store) is that putting the iPurifier in front of the ASCR sounded better than putting the iPurifier between the ASCR and the DAC. This seems to correspond with the theory you outlined above, i.e., sending a cleaned-up almost jitter-free signal into an ASCR should greatly reduce the jitter that would otherwise become re-encoded in the output data.

 

I'm secretly hoping I prefer the two in some combination to just the iPurifier alone, so I don't feel I wasted 4 times the money on the stand-alone ASCR/jitter reducer. Of course, maybe the ultimate solution is one iPurifier in front of the ASCR and one also in front of at the DAC, so that I get to spend more money. Ha!

 

BTW, I've always read that a benefit of upsampling before the DAC is to bypass a potentially more damaging digital filter inside the DAC. Could upsampling through the stand-alone ASCR/jitter-reducer in theory improve the sound, or is this just wishful thinking on my part?

 

Thanks again for all the info, and for a great, affordable product.

[AMR/iFi audio]

Would there be any benefit to placing the SPDIF iPurifier between my audiophilleo2 and my Benchmark DAC3? The AP2 claims 2.6ps of jitter, would this product reduce that number further prior to feeding the DAC?

 

For a good quality asynchronous USB to SPDIF converter with isolated outputs (e.g. like our own iLink), there is no benefit using the iPurifier SPDIF, as long as the SPDIF is short and of good quality (in the electrical sense, not all expensive audiophile cables apply).

 

 

The iPurifier SPDIF may improve the situation with asynchronous USB to SPDIF converters in two specific cases.

 

 

The first is if a very long SPDIF cable is used, by simply restoring signal quality and signal integrity, the second is by adding galvanic isolation in systems where the asynchronous USB to SPDIF converter does not include galvanically isolated outputs.

[AMR/iFi audio]

BTW, I've always read that a benefit of upsampling before the DAC is to bypass a potentially more damaging digital filter inside the DAC. Could upsampling through the stand-alone ASCR/jitter-reducer in theory improve the sound, or is this just wishful thinking on my part?

 

As with all good sounding and convincing folk tales, there is a kernel of truth here, among a large cruft of hearsay, ipsedixitism and myth.

 

If our memory serves us well, this myth originated generally with the first available ASRC chips from Cirrus Logic (CS8420) and Analogue Devices (AD1890) in the last decade of the last millennium, generally used with single-bit Delta Sigma DAC's.

 

 

In reality, if an SRC (a synchronous sample rate converter is commonly called a digital filter, an asynchronous one ASRC, but both are Sample Rate Converters, aka. SRCs) is used to up/oversample the signal to a higher sample rate and this signal is then applied to a further digital filter, we have two sets of filters daisy-chained.

 

So instead of one digital filter you now get two in series. And the result can be unpredictable, as both sets of filters combine into a new system.

 

In the "best" scenario we find that the second digital filter, which will operate at the new higher sample rate, tend to have fewer taps and less severe filter response as a lower speed digital filter in the same DAC/Digital Filter Chip. We encourage interested individuals to see what we wrote here:

 

 

iFi iDSD Micro DSD512 / PCM768 DAC and Headphone Amp. Impressions, Reviews and Comments. - Page 165

 

Then, if the first filter in the SRC may be of a non-conventional type, like a minimal low order filter because it is presumed a second digital filter in the DAC will clean up any ultrasonic signals (which probably it won't), one may end up with something that is a little like a non-oversampling or extremely minimum ringing digital filter using DAC's that in theory do not allow such filtering.

 

 

Needless to say, the digital filters in early ASRC chips were quite primitive and DAC's digital filters lacked flexibility. This is no longer the case.

 

Incidentally, many of the PCM->DSD software based conversion options out there implement a vestigial or even no digital filtering of the PCM data before rendering it into DSD, creating in effect the result (both in terms of impulse response, frequency response and leakage of ultrasonic noise) of a 'non-oversampling DAC', so we have a similar situation again. Examining the impulse response of PCM->DSD converters and correlating it with reported sound quality is quite illuminating.

 

Modern stand alone ASRC chips have standard (textbook brickwall) digital filters with no filtering options. More recent PCM-DSD conversion software implements strict digital filtering of the PCM before going into DSD. Thus it's not able to produce the same accidental "magic" as these early examples did. Generally any SRC based process is lossy, be it PCM to DSD or the other way around.

 

 

This is why at AMR/iFi we keep banging on about "bit-perfect" and "true native" processing of digital data (with digital filter selections available on hand), because no digtal conversion process (room EQ, digital domain volume control, ASRC/SRC etc.) can ever restore lost information in the audio data. At the very, very best they may have no effect in the informational sense (highly unlikely) or only introduce minimal errors and losses. Yet even those multiply each time the signal is converted in the digital domain, at the worst the introduced errors are gross.

[AMR/iFi audio]

Boys and girls, just a quick reminder. We'll attend to UK's world famous Sound & Vision - Bristol Show. As per usual, we'll show a new thing or two there, so if you're around, please come and visit us!

The date: 24th - 26th of February

The place: Marriott City Centre Hotel, Lower Castle Street, Bristol, BS1 3AD

The brand: iFi Audio / suite 11

For further info, please take a look here:

http://www.bristolshow.co.uk

See you on the spot!

[SoNic67]

I was a die-hard supporter of the "CD's need to be played in a CD player" theory, mainly because in this way the signal goes from the pickup to the DAC via i2s signals. Hence the clock is always present, separated from data, always jitter-free. This is opposed to SPDIF that embeds the clock with the data and hence is prone to jitter during transmission and recovery.

 

Well, I just jumped in the Chromecast Audio bandwagon. Bought two of them - one for the living room Denon AVR-3808CI receiver and one for the bedroom that has a new-to-me multibit DAC (PCM63J-K fed by a Yamaha SM5843A SPDIF receiver).

Needless to say that the receiver doesn't need any jitter-reduction because of the internal DSP processing (dual processors, lots of RAM).

But I tought that the multibit DAC was in need (can bennefit) of a cleaner SPDIF signal than what CCA can provide (Toslink is notoriously prone to jiiter), so... I have ordered the SPDIF iPurifier. Can't wait to hear the results.

It is nice that the results of the jitter performance where posted here, I think they should be posted on the iFi website too (I didn't find anything as technical there).

LE: I understand that the buffer memory is used in an adaptive mode, based on the incoming jitter, but I was wondering what's the actual size of the used memory?

[Nick-V]

Would there be any benefit to using this between a Chromecast Audio dongle and my Anthem MRX-300 receiver in my main system?

 

How about in my bedroom system between a Chromecast Audio dongle and my Cambridge DacMagic Plus? This review Cambridge Audio DacMagic Plus Review says the DacMagic Plus is immune from jitter, is that correct?

[AMR/iFi audio]

Would there be any benefit to using this between a Chromecast Audio dongle and my Anthem MRX-300 receiver in my main system?

 

How about in my bedroom system between a Chromecast Audio dongle and my Cambridge DacMagic Plus? This review Cambridge Audio DacMagic Plus Review says the DacMagic Plus is immune from jitter, is that correct?

 

Yes, one should see a major sonic improvement.

 

We conduct our own jitter measurements of many non-iFi as well as iFi products. Without giving any names, we recommend that you try for yourself. Let your ears be the judge.

 

The worse the jitter of i.e. $150 dac, the bigger the improvement compared to say a $10,000 dac.

 

The Spdif iPurifier benefits both. Please see previous jitter article, which has a case of a serious dac covered.

[amadeogt]

Would there be any benefit to using this between a Chromecast Audio dongle and my Anthem MRX-300 receiver in my main system?

 

How about in my bedroom system between a Chromecast Audio dongle and my Cambridge DacMagic Plus? This review Cambridge Audio DacMagic Plus Review says the DacMagic Plus is immune from jitter, is that correct?

 

After weeks of research and hesitation, I finally bought an iFi SPDIF Purifier for my Chromecast Audio.

 

Best thing ever. It makes a massive improvement connected between the CCA and the coaxial input on my DAC (a Maverick Audio Tubemagic D1). Finally Tidal sounds as good as my CDs.

[AMR/iFi audio]

After weeks of research and hesitation, I finally bought an iFi SPDIF Purifier for my Chromecast Audio.

 

Best thing ever. It makes a massive improvement connected between the CCA and the coaxial input on my DAC (a Maverick Audio Tubemagic D1). Finally Tidal sounds as good as my CDs.

 

As an approximate guide, the worse the jitter on a device, the bigger the improvement from the SPDIF iPurifier!

 

So GCA, Nvidia Shield, 4K TV have lots of room for improvement compared to say, a US$10,000 DCS.

 

We have measured a few such DACs as in our previous article.

 

And many thanks for good words. Enjoy your device!

 

 

[mordante]

Two questions

 

1) will it work between a Auralic Aries LE and a Schiit Gungnir Multibit?

2) is there a BNC version? RCA connections for 75 Ohm spdif are an abomination.

[AMR/iFi audio]

"Will it work between a Auralic Aries LE and a Schiit Gungnir Multibit?"

 

It will work in front of any SPDIF input and so far we have not encountered a SPDIF output signal that the iP SPD could not lock onto.

 

"Is there a BNC version? RCA connections for 75 Ohm spdif are an abomination."

 

BNC adapters are included. The whole 75 ohm connector story is a bit of a red herring, especially if the iP SPD is directly plugged into the DAC's input. In order for transmission line effects to become notable (which is where characteristic impedance comes in) the length (physical) of the connection must be larger in comparison to equivalent length once the rise time of the source is translated into distance at the speed of light or less (as appropriate for the cable used - assuming 68% C is safe).

 

Even at 1nS rise time (rare in any SPDIF device including iP SPD as it implies 500MHz logic devices to be used) and 100% C propagation speed in the cable we are looking at a distance of 30cm before transmission line effects become notable (note, this relates strictly to characteristic impedance, excluding ANY other factors).

 

By plugging the iPurifier SPDIF directly into the DACs input socket the actual signal path is measured in millimeters, not centimeters. So the whole transmission line caboodle is moot when plugging our product directly into DAC, using RCA or BNC connectors.

 

And the debate about 75R connectors (which incidentally measure anything except 75 Ohm regardless of rating) becomes a non-issue.

[clar2391]

I have the Oppo HA-1 DAC (which I love) and I recently encountered a problem when using it with the ifi SPDIF iPurifier. When there's no digital signal, the HA-1 makes crackling noises and the bitrate display changes, as if it were searching or trying to synchronize.

 

I contacted ifi and they said the ifi could not cause this since it's a passive device.

 

I contacted Oppo and they said that they didn't have any experience with the ifi device, but if it is a passive device, then the HA-1 may be detecting differences in the voltage (coaxial) or the signal (toslink) which is causing the error.

 

I tried the ifi on both the toslink and coax input on the HA -1 with the same noises in both.

 

Any ideas? Have any of you encountered this before?

[Snowmonkey]

I have the Oppo HA-1 DAC (which I love) and I recently encountered a problem when using it with the ifi SPDIF iPurifier. When there's no digital signal, the HA-1 makes crackling noises and the bitrate display changes, as if it were searching or trying to synchronize.

 

I contacted ifi and they said the ifi could not cause this since it's a passive device.

 

I contacted Oppo and they said that they didn't have any experience with the ifi device, but if it is a passive device, then the HA-1 may be detecting differences in the voltage (coaxial) or the signal (toslink) which is causing the error.

 

I tried the ifi on both the toslink and coax input on the HA -1 with the same noises in both.

 

Any ideas? Have any of you encountered this before?

 

I have exactly the same problem using a Micromega MyDAC. I contacted iFi support and they responded as follows:

 

The iPurifier SPDIF cannot output "random digital noise" if it has no input. It will follow whatever input is present. If not input is present, it will simply hold the last clock and transmit silence. This suggests that ultimately there is something on the source side.

 

I can't see the point in getting into a bunfight with tech support, so, since there is more than one of us with this problem I will deal with it here.

 

- It is not due to "something on the source side", because the IPurifier does it even when the input cable is unplugged.

 

- It does seem to have something to do with the DAC. It doesn't happen when I substitute a $50 no-name DAC, but the sound quality is nowhere near as good either.

 

- It definitely has something to do with the output of the iPurifier, since the MyDAC and presumably the Oppo, work fine when the iPurifier is not part of the chain.

 

-The IPurifier can be reset. If the power to the iPurifier is disconnected, then re-connected, the iPurifier remains silent until it gets some audio input. If the audio input is then interrupted, the noise starts again.

 

It is impossible to listen comfortably with the Tidal app as that generates a gap between each track, causing a burst of noise. To use Tidal, I have to bring up the Tidal web page in the Chrome browser and cast the tab to the Chromecast. As long as the tab is being cast, there is no unwanted noise from the iPurifier.

 

At this stage, I would normally chalk it up to experience and throw the iPurifier away. The problem is that when it IS playing music, the combination of the Chromecast Audio and the iPurifier sounds simply sublime. I would even consider getting a new DAC if I could find a reasonable quality one that was known to be compatible with the iPurifier. Anyone know of such a beast?

-

[AMR/iFi audio]

I have the Oppo HA-1 DAC (which I love) and I recently encountered a problem when using it with the ifi SPDIF iPurifier. When there's no digital signal, the HA-1 makes crackling noises and the bitrate display changes, as if it were searching or trying to synchronize.

 

I contacted ifi and they said the ifi could not cause this since it's a passive device.

 

I contacted Oppo and they said that they didn't have any experience with the ifi device, but if it is a passive device, then the HA-1 may be detecting differences in the voltage (coaxial) or the signal (toslink) which is causing the error.

 

I tried the ifi on both the toslink and coax input on the HA -1 with the same noises in both.

 

Any ideas? Have any of you encountered this before?

 

Without any signal the sample rate of the iPurifier SPDIF is undefined, as there is no history of any signal or any sample rate (and it covers 44.1 - 192kHz continuous).

 

After it has locked onto a signal once it will keep the previous sample rate.

 

Normally, without a locked signal the DAC should mute, it seems Oppo's DAC does not do this.

[clar2391]

Without any signal the sample rate of the iPurifier SPDIF is undefined, as there is no history of any signal or any sample rate (and it covers 44.1 - 192kHz continuous).

 

After it has locked onto a signal once it will keep the previous sample rate.

 

Normally, without a locked signal the DAC should mute, it seems Oppo's DAC does not do this.

 

It was support request #676545.

 

The Oppo doesn't make these sounds with any other inputs, with or without a signal or input.

 

 

Sent from my iPhone using Computer Audiophile

[SWL3600]

I have this same issue when connected to my Maverick Audio D2 DAC. When playback is paused, there is a nasty popping and crackling. When playback is resumed, everything is fine.

 

Sent from my SM-G920R4 using Tapatalk

[amadeogt]

I have this same issue when connected to my Maverick Audio D2 DAC. When playback is paused, there is a nasty popping and crackling. When playback is resumed, everything is fine.

 

Sent from my SM-G920R4 using Tapatalk

Sorry to hear that. Works fine with my Maverick D1 (with the iFi connected to a Chromecast Audio SPDIF out and to the Maverick over coax).

 

I bought an old Musical Fidelity M1DAC and will test it with the iFi soon. Hope it works!

 

Enviado de meu MotoE2(4G-LTE) usando Tapatalk

[SWL3600]

Sorry to hear that. Works fine with my Maverick D1 (with the iFi connected to a Chromecast Audio SPDIF out and to the Maverick over coax).

 

I bought an old Musical Fidelity M1DAC and will test it with the iFi soon. Hope it works!

 

Enviado de meu MotoE2(4G-LTE) usando Tapatalk

When I have the staic issue, the iPurifier is plugged into the D2 and fed from a DEQ2496.

 

When I put the iPurifier between my cd player and the DEQ2496 (fed from the cd player) it works perfectly.......AND has a positive influence on the sound quality. [emoji106]

 

Sent from my SM-G920R4 using Tapatalk