[OCC7N]

Are these two things the same thing?

I can not seem to find info on the difference.

 

[audiobomber]

DDC stands for 'Digital to Digital Converter'. The iPurifier3 is one example of a DDC. There are many, many other DDC's, e.g. Uptone IsoRegen, Denafrips Hermes, Singxer SU-6, miniDSP 2x4 etc. Not all do the same things, or in the same ways.

A DDC receives a digital signal, processes the signal, and outputs a different type of digital signal. Some clean, re-clock, convert to another format, split frequencies, etc. An iPurifier3 is a DDC that can do a few of these things.

 

[Ludique]

Let’s not call iPurifier3 or ISO Regen a ddc since they don’t convert anything. They are more like filters.

 

[Andrew_WOT]

iPurifier3 only provides galvanic isolation, there is no DDC in there.
Now discontinued iGalvanic3.0 provided both, reclocking and isolation. Guess demand wasn't super high that iFi dropped it.

 

[audiobomber]

iPurifier3 only provides galvanic isolation, there is no DDC in there.
Now discontinued iGalvanic3.0 provided both, reclocking and isolation. Guess demand wasn't super high that iFi dropped it.

Let’s not call iPurifier3 or ISO Regen a ddc since they don’t convert anything. They are more like filters.

iPurifiers absolutely are DDC's. They receive a digital signal, process it and output a digital signal:
- Active Noise Cancellation, REclock, REgenerate, REbalance
https://ifi-audio.com/products/ipurifier3/

and so is the IsoRegen:
- completely REGENerates the data signals
- isolate the power and signal grounds from computer/stream USB sources
- ultra-low-phase-noise oscillator (Crystek CCHD-575), “Femtosecond” low jitter clock
https://uptoneaudio.com/products/iso-regen

 

[OCC7N]

iPurifier3 only provides galvanic isolation, there is no DDC in there.
Now discontinued iGalvanic3.0 provided both, reclocking and isolation. Guess demand wasn't super high that iFi dropped it.

But it says it does reclock on the 2nd gen

 

[GoldenSound]

Are these two things the same thing?

I can not seem to find info on the difference.

The key thing is that USB works entirely differently from I2S/AES/SPDIF.

I2S/AES/SPDIF are synchronous protocols. Along with the digital data for your music which is sent in a constant stream, the source device also provides a clock signal to the DAC. The DAC will convert the incoming data at the rate it receives it, instructed by the incoming clock signal.
This clock signal therefore you want to be as high quality/low jitter as you possibly can get, as this will result in a better quality conversion.
(There are many DACs with various buffering or PLL systems to reduce jitter, but the TLDR is that with a synchronous source you want the clock signal to be as close to perfect as you can get).

USB however is asynchronous, and differs in two key ways.
Firstly, data is not sent in a continuous stream, it is sent in chunks that are put into a buffer in the USB implementation of the DAC.
The Device then feeds samples (in I2S format) from the buffer and converts them, but does so at its OWN rate, using its own clocks.
The USB source is not providing a clock signal to the DAC.

For this reason, DDCs and USB cleanup devices are quite different.

USB devices can reduce noise, and improve overall signal integrity, but do not affect jitter, and there is no evidence that USB 'Reclocking' (which is actually basically just a USB repeater) will provide any performance benefit other than allowing you to use a longer connection. Cause the USB audio data is not in a stream and the DAC is not using any clock signal from the USB source.
The reduction in noise however can help the DAC itself to perform better.

I2S/SPDIF/AES reclocking though, DOES directly affect performance, as your DAC is using the clock signal from the source

 

[OCC7N]

The key thing is that USB works entirely differently from I2S/AES/SPDIF.

I2S/AES/SPDIF are synchronous protocols. Along with the digital data for your music which is sent in a constant stream, the source device also provides a clock signal to the DAC. The DAC will convert the incoming data at the rate it receives it, instructed by the incoming clock signal.
This clock signal therefore you want to be as high quality/low jitter as you possibly can get, as this will result in a better quality conversion.
(There are many DACs with various buffering or PLL systems to reduce jitter, but the TLDR is that with a synchronous source you want the clock signal to be as close to perfect as you can get).

USB however is asynchronous, and differs in two key ways.
Firstly, data is not sent in a continuous stream, it is sent in chunks that are put into a buffer in the USB implementation of the DAC.
The Device then feeds samples (in I2S format) from the buffer and converts them, but does so at its OWN rate, using its own clocks.
The USB source is not providing a clock signal to the DAC.



For this reason, DDCs and USB cleanup devices are quite different.

USB devices can reduce noise, and improve overall signal integrity, but do not affect jitter, and there is no evidence that USB 'Reclocking' (which is actually basically just a USB repeater) will provide any performance benefit other than allowing you to use a longer connection. Cause the USB audio data is not in a stream and the DAC is not using any clock signal from the USB source.
The reduction in noise however can help the DAC itself to perform better.

I2S/SPDIF/AES reclocking though, DOES directly affect performance, as your DAC is using the clock signal from the source

so on my rme adi-2 fs I need something to relock the spdif signal?

Right?

 

[dcguy73]

so on my rme adi-2 fs I need something to relock the spdif signal?

Right?

Saying you “need” something to reclock the SPDIF signal to your DAC implies that there’s something wreong with the SPDIF signal in the first place (that it needs to be reclocked). I think the need is individual to the gear involved in the equation. But I defer to @GoldenOne, who seems to be much more knowledgeable on the subject.

 

[gimmeheadroom]

Are these two things the same thing?

I can not seem to find info on the difference.

I think a useful distinction is that DDC is expected to provide good connectivity and format conversion(s). In comes USB, coaxial S/PDIF, optical S/PDIF, AES, etc., and out they come again over AES, IIS, coax, optical, etc.

You can argue that a USB->USB decrappifer is a DDC but I don't think that helps anybody. Seems more reasonable to acknowledge the difference, because they are for different use cases.

 

[sungmj]

so on my rme adi-2 fs I need something to relock the spdif signal?

Right?

RME DAC (All DACs) includes DDC (Digital to Digital Converter) and SRC (sample rate converter), before pcm format digital signal to analog signal.

The reason ppl want to use an external DDC is usually separate DDC unit has better clock and better capability in converting between digital format. The reason iPurifier advertise their device as 'purifying' device when it really by nature DDC is..

1. iPurifier doesn't provide full DDC feature sets that other external DDC provides..
2. its focus is (I believe) re-clocking, sound improvement or 'purifying' comes from this re-clocking mainly.

I don't know how active noise cancellation is applied here w/o first converting signal to analog?

 

[OCC7N]

My sound chain is this:

Computer - USB3.0 cable -> iPurifier3 -> RME ADI-2 DAC FS -> XLR -> Active Speakers

But if USB aint good enough then I am waisting my time saving up for a weiss dac?

 

[gimmeheadroom]

My sound chain is this:

Computer - USB3.0 cable -> iPurifier3 -> RME ADI-2 DAC FS -> XLR -> Active Speakers

But if USB aint good enough then I am waisting my time saving up for a weiss dac?

USB is good because it's very high speed. USB is bad because it has the potential to carry noise.

It's a slippery slope. If your system sounds good to you with no sonic defects, stop, you're done. If you have electrical noise that you can prove is coming from USB then you have options. A decrapifier might be enough.

If you want connectivity options, reclocking, etc. then you can look into a DDC. But, the rest of your system has to be resolving enough to capitalize on it. The RME is extremely good. But, the amps in active speakers are not taking advantage of that.

 

[gimmeheadroom]

RME DAC (All DACs) includes DDC (Digital to Digital Converter) and SRC (sample rate converter), before pcm format digital signal to analog signal.

The reason ppl want to use an external DDC is usually separate DDC unit has better clock and better capability in converting between digital format. The reason iPurifier advertise their device as 'purifying' device when it really by nature DDC is..

1. iPurifier doesn't provide full DDC feature sets that other external DDC provides..
2. its focus is (I believe) re-clocking, sound improvement or 'purifying' comes from this re-clocking mainly.

I don't know how active noise cancellation is applied here w/o first converting signal to analog?

It's seems extremely doubtful (ok, unbelivable) that the iPurifier reclocks. Real DDCs are expensive, because stable clocks are expensive. People are spending 5,000 euros for standalone clocks. Let's face it, the small portable decrapifiers might help, but don't expect them to provide good reclocking or any reclocking in most cases.

 

[sungmj]

It's seems extremely doubtful (ok, unbelivable) that the iPurifier reclocks. Real DDCs are expensive, because stable clocks are expensive. People are spending 5,000 euros for standalone clocks. Let's face it, the small portable decrapifiers might help, but don't expect them to provide good reclocking or any reclocking in most cases.

i know right? any decent DDCs that does good reclocking costs $$$. but that's what ifi claims.. reclock, rebalance, etc. like you said the quality I.. doubt it too.