Trying to achieve HiRes Streaming on Phantoms

[Charcharius]

If you use RAAT directly from Nucleus to Phantom Roon will downsample to 48kHz (or 44.1 depending on the source rate and how you've set up Roon). […] Because Phantoms handles max 48kHz. One can send higher rez to Phantoms (via UPnP for example), but Phantoms would internally downsample to its own working rate.

This is the statement I’m looking to confirm.  I understood that the new Phantom I’s use an updated ADH amplifier, but wasn’t sure if that meant they have an updated DAC as well.

[ogs]

but wasn’t sure if that meant they have an updated DAC as well.

I believe the DAC in Phantoms (old and new) can handle up to 192kHz, but communication from one Phantom to the other in a stereo pairing is set to 48kHz. Hence the stream (even to a single Phantom) is limited to 24/48.
48kHz may have been the limit since Phantom was introduced many years ago. Devialet just didn't tell us... When RAAT was enabled recently this was revealed by looking at the Signal path in Roon. Devialet also changed the Phantom spec to read 48kHz. I think one can still stream 192kHz to Phantoms (96kHz for sure) via UPnP, but the speaker will downsample to 48kHz. So this is a choice Devialet has made, not a hardware limitation as such.

[edgecrush3r]

This makes sense indeed as the stereo communication between the speakers needs to be pretty flawless. This also suggests that the highest bitrate would be by connecting an external DAC and feeding each Devialet through seperate RCA cable for left and right. Any thoughts on this?

Also note: older forum posts mention that SQ would be better over PLC or Ethernet. However i have not found any proof on this?! Could it be, that the bitrate is higher when using PLC or Ethernet?

[ogs]

I have recently learned, through a support case I submitted on the Roon forum https://community.roonlabs.com/t/no-mqa-...old/155440 , that RAAT, or indeed any stream, at 48kHz will not allow decoding of MQA. If the device or DAC does not support 88.2 and 96kHz MQA first unfold will not be performed by Roon

[Charcharius]

Thanks for sharing. Interesting but frustrating. I’m thinking I should invest in a BlueSound Node 2i and try that path (decodes/renders MQA) but with a desire for a Roon Core and some Phantom I’s, it may have to wait. :/

[edgecrush3r]

Roon Core is always a nice option as it opens many doors to streaming audio, given that you also have Tidal or Qobuz.

So to narrow the initial question down: how to get Hi-Res.
As mentioned before, if you have a stereo pair anything will be mixed down to 24bit/48kHz as @ogs mentioned. Even connecting a Node 2i will not change that if you planned to use Optical and not RCA (skipping the DAC of the Phantiom). The other option, would be to run the Phantoms into Direct Mode.. in that case you could use two optical cables but you will need to split into steroe somehow. Toslink is capped at 24/96 i believe.

So the only easy solution i guess is to not use the DAC of the Phantom at all and go from your Streamer/DAC such as Node2i straight into two RCA/mini-jack cables. You will need to break stero mode, and just use 2x sets of RCA cables to minijack. Ommitting right channel on left speaker and vice versa. This way you will havr proper analogue Left and Right, while the streamer Node2i/Raspberry will also do DAC. this way you can stream at whatever bitrate your DAC allows you and thus only uses the Phantom for amplification.

[ogs]

not use the DAC of the Phantom

I think this is not possible. There is no way of bypassing the DAC in any of Devialet's products AFAIK. The Reactor (Phantom II) has an additional ADC (like Expert amps) for digitizing analog signals, but this is again run through DAC stages after cross over and other DSP corrections (SAM etc.). Phantom I is similar, but has only digital inputs. If it is Optical direct you refer to it only reduces latency by bypassing some of the "expensive" DSP functions.

[edgecrush3r]

not use the DAC of the Phantom

I think this is not possible. There is no way of bypassing the DAC in any of Devialet's products AFAIK. The Reactor (Phantom II) has an additional ADC (like Expert amps) for digitizing analog signals, but this is again run through DAC stages after cross over and other DSP corrections (SAM etc.). Phantom I is similar, but has only digital inputs. If it is Optical direct you refer to it only reduces latency by bypassing some of the "expensive" DSP functions.

ADC  that would mean everything gets re/sampled even if you put a nice DAC in front. Thats painfull  I thought that the Analogue signal would just pass through and not go through an ADC=>DAC as that would completely destroy anything near bit-perfect streaming. An ADC is needed when steropair is used (transmission to the other speaker would be digital), however i hope that the Analogue signal would not pass a ADC/DAC combo if you dont use pair them as stereo (as there is no need for ADC in that case). This exposes some serious limitations for HiRes streaming if ADC is always in the path of the signal.

Maybe we can test something and measure the output using a UMK-MK1 mic or something similar: https://appuals.com/how-to-determine-the...udio-file/

[ogs]

not use the DAC of the Phantom

I think this is not possible. There is no way of bypassing the DAC in any of Devialet's products AFAIK. The Reactor (Phantom II) has an additional ADC (like Expert amps) for digitizing analog signals, but this is again run through DAC stages after cross over and other DSP corrections (SAM etc.). Phantom I is similar, but has only digital inputs. If it is Optical direct you refer to it only reduces latency by bypassing some of the "expensive" DSP functions.

ADC  that would mean everything gets re/sampled even if you put a nice DAC in front. Thats painfull  I thought that the Analogue signal would just pass through and not go through an ADC=>DAC as that would completely destroy anything near bit-perfect streaming. An ADC is needed when steropair is used (transmission to the other speaker would be digital), however i hope that the Analogue signal would not pass a ADC/DAC combo if you dont use pair them as stereo (as there is no need for ADC in that case). This exposes some serious limitations for HiRes streaming if ADC is always in the path of the signal.

Maybe we can test something and measure the output using a UMK-MK1 mic or something similar: https://appuals.com/how-to-determine-the...udio-file/

Yeah, if you put a DAC before the analog input of the Phantom II it will be re-digitized. All signal processing in Phantoms (and Experts) like volume, SAM, cross over is done in the digital domain.
The signal between units is also digital. The ADC (Analog to Digital Converter) is only used for input from an analog source, never anywhere else.

[eniriop]

Welcome to the forum...

Who knows what RAAT will bring to the Phantoms?  Unfortunately, Devialet had a poor record with the introduction of RAAT on the Expert Pro....

There is no problem with playing HiRes, up to 24/192.  But with Tidal and dodgy MQA (may have better master recording, often louder than the CD tracks), the resolution is determined by Roon.

If you want to improve streaming, look at getting an Uptone  EtherRegen.

Thank you for your reply!
Is there however a specific reason that the streaming from Qobuz in HiRes is consistently awful?

I use Audirvana 3.5.44 to stream Qobuz Hires files up to 24/96khz on my Phantom golds or reactors.  With optical out there is no problem. Using UPNP i may get some gaps for a few seconds.