[Jawed]

So this evening I was briefly sat not listening to music and I could hear hiss from my speakers! That's not right I thought, DAVE driving my speakers (91dB/W/m at 1.6m listening distance) is absolutely silent. Why is there hiss? OK, so I've got the volume a bit louder than normal, but DAVE never gave me hiss before I got HMS.

So then I played with inputs and discovered that HMS being active is causing the hiss! If I stop the audio to HMS then the hiss disappears and I'm back to blissful silence from DAVE.

So, remembering that Blu 2 has a dither option switch which can be used when connecting Blu 2 to a non-Chord DAC, I thought about bit depth. With Blu 2 the dither is used to create a 16-bit output that is compatible with an old type of DAC.

So on my computer I changed the bit-depth to 24-bit, instead of the default 16-bit. Now, there's no hiss from DAVE even when "silence" is playing through HMS. So it seems that HMS detects that the input is 16-bit and it outputs dithered 16-bit audio (at 705.6 KHz). The dithering is what I was hearing as hiss with HMS feeding into DAVE.

This seems to be a problem though: anyone who is using a CD transport into HMS is feeding HMS with 16-bit data. HMS then adds dither. The dither is completely pointless if you have a Chord DAC. And worse than that, the dither is audible!

@Rob Watts is this behaviour by HMS intentional? This seems like a bug to me. It's easy for me to solve this problem, but anyone using a CD transport into HMS seems to be stuck! Also I suspect anyone using a streamer that outputs 16-bit audio will have the same problem. In my setup I'm using optical. Perhaps this problem only affects S/PDIF audio (optical and electrical), so USB is fine?

Now playing: Stephen Cleobury, Choir of King's College Cambridge etc. - Lassus: Choral Music

 

[Rob Watts]

No Hugo M scaler has no dither option, nor is dither added at all when using the full 1M taps. 16 bit data is treated identically to 24 bit data - actually 16 bit data is 24 bit with 8 zeroes.

I think you are just hearing the 16 bit dither being added via your PC when you set it to 16 bit mode (which you should never do as 24 bit sources will get truncated and re-dithered).

 

[musickid]

I just paused the music with hms being fed 16bit/44kHz. Optical into hms from my imac. I hear no hiss just complete silence.

 

[Triode User]

Very unlikely because the server is just a computer and computers produce a lot of RF noise. The Innuos Zenith SE, for example, does not have a good track record as a low RF noise source.

An interesting statement. I and others may beg to differ with you on that so I wondered where you had got that information as I have not seen anything indicating it.

 

[Jawed]

No Hugo M scaler has no dither option, nor is dither added at all when using the full 1M taps. 16 bit data is treated identically to 24 bit data - actually 16 bit data is 24 bit with 8 zeroes.

I think you are just hearing the 16 bit dither being added via your PC when you set it to 16 bit mode (which you should never do as 24 bit sources will get truncated and re-dithered).

Thanks Rob, that makes sense!

 

[tunes]

No you can use the supplied bnc cables and add an audio quest adapter on the end. If you search thread for audioquest you’ll find more posts.

So why spend $200 when the Audioquest adapter and 2 gold plated BNC connectors run ~ $16 on eBay. Would there be any difference in SQ between these two options??

 

[musickid]

Rob stated excellent results with adaptors. I prefer the adaptor method. It strikes me as the more technically correct and tested method. Of course 75ohm bnc cables must be used. Higher quality cables than those supplied are easily available.

 

[tunes]

So one light stays on forever? Is it always the upsampling light?

What does the DX OP light mean. On the remote it cycles through black, green and white but always defaults to red. The user manual just states “refer to partnering in product manual”

 

[ZappaMan]

So why spend $200 when the Audioquest adapter and 2 gold plated BNC connectors run ~ $16 on eBay. Would there be any difference in SQ between these two options??

What costs 200 ?

 

[musickid]

Incoming sample rate. DXOP light.

See my photo above tunes. Concerning adaptors my audioquest adaptor is shown.

200$ for moon audio's twin bnc to coax cable for h2/hms.

 

[tunes]

What costs 200 ?

 

[supervisor]

i have one of the cables for sale... PM me

 

[Amberlamps]

What costs 200 ?

This one time at band camp.....

Suffice to say, the words red, light and district are involved.

TOTL

 

[CRITICALSHOT]

This one time at band camp.....

Suffice to say, the words red, light and district are involved.

TOTL

 

[musickid]