I mostly stream my music but when playing a CD, I use the players analogue output into the preamp. However yesterday I purchased a RAC to BNC digital cable so that I could use the significently better DCA capability of my Rossini APEX.
The sound quality via the Rossini is much better than the native CD Player - however I noticed that Mosaic is reporting the input from the CD player as 20bit/44.1 kHz vs 16bit/44.1 kHz.
The Rossini DAC is also connected to a Rossini Clock - and I understand that even though the clock is switched on and connected, the external clock is not used in the case of SPDIF input.
Any thoughts as to if I have a faulty coax cable or if there is a software issue that showing the incorrect bit rate
I am a little confused and would be grateful for seem clarification.
You have a CD player. However what is it? Does it have a wordclock input?
What is a RAC to BNC cable? Do you mean BNC/BNC and are connecting the Rossini wordclcok output 3 to the CD player’s wordclock input? If so how are you connecting the CD player digital output to Rossini , is that the coax?
The dCS wordclocks are electrically and mechanically better places for the crystal. The clock in Rossini DAC is then referenced to this, thus the DAC processor not the inputs. However ensure that the Rossini wordclock outputs 1 and 2 are matched to the DAC wordclock’s inputs 1 and 2 respectively and have not been inverted.
I am guessing that Rossini will report what it is actually receiving and show this on its front panel display. This should also be shown on your device using Mosaic. Is this happening or are you saying that only Mosaic shows this ?
Although it has been held that the information retrieved from HDCD encoded discs could be regarded as the equivalent to having 20 bit when decoded, the disc remained as 16 bits. It used the LSB as a “container” for the additional data. Not dissimilar in concept to MQA.
I have quite a few HDCD encoded discs as they were a popular format for Warners back in the day. I never had a player with a decoder though. They play as 16bit.
CD/SACD player is a Yamaha CDS3000 (got this as I wanted to be able to play both CD and the SACDs I have)
I am using the digital output from the CD player connected to the Rossini (which is also happens to be connected to a Rossini clock - the clock switched on automatically when the Rossini DAC is switched on as I have a d-type cable connecting the DAC and the Clock). The digital cable I am using is a Tellurium Q Black Waveform digital cable - which has a RAC plug at the CD side and a BNC connection at the Rossin end - the cable is connected to SPDF 2 at the Rossini end (which is a BNC connector).
When I play a normal CD on the CD player, the dCS Mosaic app shows that the source on SPDF 2 is 44.1 kHz (which is correct of course) but at 20 bit (vs 16 bit which is what I would expect)
The CD in question is a normal CD - not a SACD or HDCD. I tried a couple of different CD and all of them showed the same frequency (44.1 kHz) and 20 bit (rather than 16 bit) on the Mosaic app.
It will be interesting to find out what he is using. Was it an HDCD encoded disc being decoded with a player equipped with a decoder and does its digital out port send a decoded yet still digital signal or a redbook one? Unknown territory currently.
Anyway it is easy for @fernar to check. Just load another non-HDCD disc.
EDIT: While wring and posting he above @fermat’s latest arrived. The Yamaha was released in 2014 well after the demise of HDCD when Pacific Microsoncs was bought by microsoft who seem to have warehoused the IP. There is no mention of HDCD in Yamaha’s blurb. So I don’t think the solution is to do with this. Anyway he says that standard discs are involved. I assume that the playing of SACDs requires theYamaha analogue outputs connected to his preamp.
I don’t know what an RAC plug is . Looking at a photo of the Yamaha’s rear panel digital out is optical or coax. So is this simply a coax to BNC cable?
I am still unsure if the 20bit info is showing on both Rossini front panel and Mosaic or just Mosaic.
When playing music from Qubuz, all tracks have correctly identified sampling freqency and bitrate shown, also the Rossini clock switches to Worldclock Auto. When playing a CD and selecting the input to SPDIF 2, the clock switches to Audio (as it should correctly do so) and the Rossini goes back to showing 44.1 kHz/20 bit. I now noticed that the bitrate does actually alternatate over time from 20 bits to 16 bits
Not sure if I should stop worring about this as the music sounds great
The S/Pdif input is connected to the Yamaha CD player. Your Rossini displays the bit depth and sampling frequency rate that it actually receives. So the conclusion is that the Yamaha is putting out a 20 bit signal. So it seems to be padding the bit depth ( adding digital zeros). Unexpected.
dCS DACs show the specs for the actual audio that is being played and not just the top level “container” details so when it shows the number of bits then it is showing the number of active bits in the incoming audio data stream.
So if the Rossini is receiving 24bit audio data but only 16bits of that audio data is “active” and in use then the Rossini will show 16bits instead of 24bits.
This has been queried a few times over the years and is, just as @PAR has already mentioned, exactly as it is supposed to be (as far as our DAC and its display is concerned) so nothing to worry about but it is interesting that your CD player seems to be outputting 20 (active) bits of audio.
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yes, RCA not RAC - I was compairing breakdown cover…
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