[Rob Watts]

If the DAC is connected via optical only, and the only connection to earth is via the PSU, then no current can flow. The only other path is via parasitic capacitance to ground, and I have calculated/estimated that to the order of 0.1pF. From listening tests that is not enough to cause a SQ issue.

With HMS/TT2 you would have about 2pF (that's the capacitance of the isolator on the BNC drivers) ground loop connection around the mains, HMS, TT2 and back to mains. But this would be fixed by battery feeding HMS, or by using multiple solid core 2GHz ferrites on the BNC cables connecting HMS to TT2, as this increases the RF impedance thus breaking the loop caused by the 2pF isolation capacitance.

We are actually talking about ultra small currents causing audible changes; I keep on getting surprised how ultra small things can have an easily audible change - this is the amazing thing about putting numbers onto errors and then doing rigorous listening tests - I am constantly finding that these numbers are ridiculously small.

 

[ZappaMan]

I had thought the shared ground plane issue, was less about direct connection of source to dac, but that all components would become connected via the mains, and create a network. Then if mscaler was very “noisy”, it could travel to the dac via the mains.
but I don’t understand these things tbh.

 

[Rob Watts]

That's true about voltage; but that's not important with ground plane noise, and that's just about the source inducing current flow into the DAC ground plane. The finite impedance of the PCB ground plane then induces voltage drops across the ground plane, and then the analogue electronics will create noise floor modulation. A simple voltage on earth isn't a problem unless it creates currents across the DAC ground plane.

I know it's not easy to get one's head around this stuff...

 

[thePhones]

If the DAC is connected via optical only, and the only connection to earth is via the PSU, then no current can flow. The only other path is via parasitic capacitance to ground, and I have calculated/estimated that to the order of 0.1pF. From listening tests that is not enough to cause a SQ issue.

With HMS/TT2 you would have about 2pF (that's the capacitance of the isolator on the BNC drivers) ground loop connection around the mains, HMS, TT2 and back to mains. But this would be fixed by battery feeding HMS, or by using multiple solid core 2GHz ferrites on the BNC cables connecting HMS to TT2, as this increases the RF impedance thus breaking the loop caused by the 2pF isolation capacitance.

We are actually talking about ultra small currents causing audible changes; I keep on getting surprised how ultra small things can have an easily audible change - this is the amazing thing about putting numbers onto errors and then doing rigorous listening tests - I am constantly finding that these numbers are ridiculously small.

Just tested this with my powerbank and things do sound warmer to me. It‘s like strings and percussion lost a bit of the aggressive edge. Can you or someone else recommend a solid ferrite for using on the 2m cable with HMS/Dave for building a cable. I really don‘t want to charge my powerbank everyday

 

[Triode User]

@Rob Watts Hi and I hope you are well and looking forward to being allowed out! I have not been intentionally ignoring you or your comments, I just had to deal with a little matter of a failed wisdom tooth extraction which rather took over my life for several days.

Many thanks once again for injecting the benefit of your knowledge and for considering this further. All my comments are based on what I hear. For instance I have two different CD players and when I connect them for instance to Dave by optical they sound quite different. I will do more listening to other sources connected by optical and see if I can find any pattern to the differences. None of my listening is with headphones (I don’t own any) and I always either use my active ATC speakers or my power amps connected to speakers.

With your laptop, am I right in recollecting that you use it with its battery rather than with the charger plugged in for critical listening? I admit though that even if that is a correct recollection I cannot remember if you were using usb or optical.

If you suspect issues with your source, then just use your mobile phone with bit perfect app - you can use USB - as the phone is isolated from ground, so you can't get any ground plane noise from this. If your source sounds identical, or close to identical, then don't worry about the source from a SQ POV

On this I have spent several hours today listening to an iPad (battery only for the ipad, no charger) outputting by usb to my Qutest. I compared this to my usual Innuos Zenith streamer (mains powered). Both were streaming the same file. I simply swopped over the usb cable between the two. The iPad usb option consistently had a hard edge to the treble and it seemed to artificially enhance the treble. This was with Qobuz and also with ripped files (44.1/16) stored on a local hard drive accessed by both the iPad and the Zenith. The iPad was really quite fatiguing to listen to and it was a relief to swop over to the streamer. I checked on the digital streams and both seemed to be supplying the same bit perfect signal from the same source. I have compared notes with a few other people and they say they also have similar poor experiences with using an iPhone in a similar way.

This is perplexing as your experience seems to contradict this and I wonder why we are hearing different things.

 

[118900]

deleted

 

[Triode User]

are we letting him out?

It could be a negotiated thing, perhaps a new device being launched in return for a limited amount of freedom!

Although I have just listened to the UK R4 news and foreign travel does not seem likely this summer . . .

 

[miketlse]

are we letting him out?

He is secure in his skunk works in Wales, but can only travel to England.

 

[Ragnar-BY]

@Triode User
I have similar opinion. It’s not only about batteries. My MacBookPro sounds significantly worse (less depth, more harsh) than my opticalRendu, despite the fact that MBP is running on battery and oRendu is on mains. Both playing same records with Roon via USB.

 

[Vyyy]

In my experience windows usb laptop - harsh edges.
I listen Android USB out via audio player pro.
I have made many test - android usb is relax and soft. Even the praised mac mini in my ears is harsh. Usb android after many test has relax soft highs and better bass definetely. I am using usb out android and stream qobuz.

I have also tried 2go - and this is marvelous. It adds more micro details while retaining android bass and relaxed highs.
This is why ibordered 2go 2yu. Dealer told me that on next shipping i might receive.

By the way i was impressed by auralic g1 streamer.
Made AB test with proac d30rs (switcing inputs on sugden ia4) qutest with auralic g1 against hugo2/2go and to my surprise there was no any difference at all. At all.

Same test were done using macmini, windows and android and above all is just android.

1st cheap solution android.
2nd if you can afford 2go or dedicated streamer like auralic g1.

 

[118900]

deleted

 

[feddar]

...I have also tried 2go - and this is marvelous. It adds more micro details while retaining android bass and relaxed highs.
This is why ibordered 2go 2yu. ...

Are you plugging this into the HMS via optical?
Also, how do you control the source? Is it a Hugo app on you phone?

Thanks,

Fed

 

[Vyyy]

Are you plugging this into the HMS via optical?
Also, how do you control the source? Is it a Hugo app on you phone?

Thanks,

Fed

No, just usb.
Once i will receive 2go2yu i will test all outputs.

I use Android USB player pro, with 2go test unit used BubbleUPNb qobuz stream

 

[feddar]

Thanks. I like USB player pro as well.

I was thinking of the Bluesound Node2i, or Vault2i, via optical to the HMS. Any comments?

 

[Triode User]

Thanks. I like USB player pro as well.

I was thinking of the Bluesound Node2i, or Vault2i, via optical to the HMS. Any comments?

i had a 2i and I like the control software with it. Here in the uk there is quite an interest in removing the smps from the 2i and inserting an interface board which allows external power supplies to be used. That is what I did with mine and liked the result very much.