Frode said
The confusion here is the use of the HDMI ports. This makes owners think that this port has anything to do with HDMI audio or video, but it doesn't. These ports (with a HDMI cable in-between) are used as a practical way of transferring I2s signals. I2s is the standard way of transferring the digital signal between your CD transport and the internal electronics within the CD player (e.g. DAC). PS Audio has extended this transfer between 2 devices by using the very core signals and thus fewer conversions.
Yes, but my questions remain.
Why would we want to use the I2S inputs if we don’t have a PWT? Is this a better mechanism than the bridge,usb, etc?
Would it be possible to connect a computer music server to DS via HDMI with a driver and/or custom cable? This would make it availabel to a lot more people.
This has already been addressed. Check the compatible I2s sources in the Google spreadsheet already linked to. The LH Labs Geek Source will arrive in Q1-15 (not on this list).
I thought I was clear on this too. Someone else has to step in and explain this better than me.
billg said
1. Why would we want to use the I2S inputs if we don't have a PWT? Is this a better mechanism than the bridge,usb, etc?
Would it be possible to connect a computer music server to DS via HDMI with a driver and/or custom cable? This would make it availabel to a lot more people.
The PS Audio Nuwave Phono Converter has a compatible I2S output. As has been mentions there are other devices which also talk I2S.
I2S isn’t really designed to go long distances reliably but since it has a clock on a separate wire it can be less jitter sensitive than AES/EBU, S/PDIF or TOSLink. On the DirectStream this is less of an issue and I wouldn’t go out of my way to use I2S instead of another more common connection, but I’m sure that there are plenty of systems where, for whatever reason, I2S dilivers a cleaner signal than the others (and vice versa.)
HDMI is a spec, it not only specifies the standard hardware (plugs, sockets and minimum quality for HDMI cables, the signals, encodings, pinouts, etc.) but the “software”, i.e. the protocols and signaling. If it were cost effective we would have explicitly included HDMI as a feature in the DS (and probably other PS Audio products.)
You can buy boxes with HDMI receivers that output the audio on one or more of I2S, S/PDIF, AES/EBU, USB, etc. They aren’t cheap.
I2S is a superior format for transferring data between a transport and a DAC. It is the native format within CD players and DACs. PS Audio is using this format to go directly from the PWT as transport to the PWD or DS.
For the typical S/PDIF, I2S is converted to S/PDIF, sent out to the DAC, and then again converted within the DAC to I2S. PS Audio’s implementation of I2S avoids all this.
As Frode explained, the output from a computer music server is entirely different than I2S. Merely using a custom cable with the appropriate connectors on each end will not make it work.
Elk said
1) I2S is a superior format for transferring data between a transport and a DAC. It is the native format within CD players and DACs. PS Audio is using this format to go directly from the PWT as transport to the PWD or DS.
My understanding is that there is not an industry wide implementation standard in terms of pins used for I2S over HDMI at this time. I have no knowledge of the politics of the HiFi industry. However it would seem to me that before various implementations of I2S over HDMI become too entrenched that maybe now is the time for the industry to adopt an agreed common standard. This would be of overall benefit of the consumer. Or have the various implementations developed too far already?
You are absolutely correct assuming this. There are a lot of proprietary I2s implementations out there and it is not only the pin and signal configurations that differs but also the type of connector. Some also uses RJ45 and Cat x (Ethernet) type.
Since the I2s is supposed to be an internal ‘bus’ there should be no reason for specifying outboard connectors as part of the standard. The problem is that you can never be 100% sure about any interoperability issues without trying it first, as we discovered with the PWD MKII NativeX implementation.
Personally I see no point in conversions between I2s and S/PDIF. Either you go direct with a minimum of conversions (for maximum gain) or you just forget about it.
billg said
Oh well, it's fortunate I'm very happy with my bridge then.
I also was very happy with the bridge, save for the dropouts and lack of gapless play, until I bought the Rendu streamer. The sound improvement over the bridge is remarkable. The setup was easy too. Now better sound, no drops and gapless...perfect with the DSD.
Does anyone know if the new Aria streamer which has I2S output is compatible with the DS? It uses cat 6 type output jack does anyone make an adapter to HDMI connector?
dew1551 said
Does anyone know if the new Aria streamer which has I2S output is compatible with the DS? It uses cat 6 type output jack does anyone make an adapter to HDMI connector?
aria’s audio card is provided with an I2S output which allows for low-jitter, high-quality connection to D/A converters provided with an I2S input. Alas, aside the signals set, no standard is provided for an extra-equipment I2S connection. Various voltage standards, pinouts and connectors are used in various D/A converters which make the connection with aria’s audio card more difficult. This application note focuses on signals voltage and format adaptation in order to have aria’s audio card working with all D/A converters on their I2S input. The user is supposed to be acquainted with the various connectors and the most common voltage standard used in this application. VOLTAGE STANDARDS AND CONNECTORS Various standards and connectors are used for I2S inputs on D/A converters. Amongst voltage standards: •TTL/CMOS single-ended •TTL/CMOS differential •LVDS •ECL LVDS is becoming widely used on commercial D/A converters because of its immunity to noise and capability to drive long cable runs. TTL/CMOS single-ended is more common on DAC boards for DIY’ers. aria’s audio card offers a simple 3.3V CMOS (5V TTL compatible) output. Amongst connectors: •RJ-45 •HDMI •Strip The HDMI connector is generally associated with LVDS format (but this is not necessarily true, so please check specifications before assuming that LVDS levels are carried in on an HDMI connectors), while RJ-45 and the strips are more commonly used with single-ended and differential formats. aria’s audio card uses an RJ-45, 8 pins connector with the following pinout (left to right): 1) SDATA 2) GND 3) LRCK (FS) 4) GND 5) SCLK (BIT CLOCK) 6) GND 7) MCLK 8) GND Signals are LVCMOS,that is CMOS levels at 3.3V supply. They are TTL-compatible, that is, they can directly drive a 5V TTL input stage without need for level translation. The hiFace Aria’s audio card’s I2S output is drive by a high current driver, so it can directly feed an input when no level translation is needed.
They are the I2S signals, we expect them as LVDS not CMOS, but they should work if wired to the correct pins and the other halves of the LVDS pairs are pulled to, say, 1.5VDC. FWIW we don’t care about the master clock.
I just start using Directstream with USB connection and wondering if I’m missing something not using I2s, I have here in my hands few interfaces that may can send I2s signal, Exa2ui, amanero and also Exd, I think that I can use it as interface to DS ? it will better than pure USB ?