Chord Qutest question ...

[Tony L]

I understand and partly agree with the arguments Chord make for using SMPS, but the amount of leakage current going into the chassis of the TT2 and Mscaler really should be sorted. One hand on the mains chassis grounded Sugden amp and then lightly touching the Chord product with the other hand givers that finger tingling/static feeling which tells you the PSU leakage is rather higher than it should be in products of this cost. They all do it - TT2, Mscaler, Huei, Anni, Qutest.

I’ve always assumed that was a grounding thing. MacBooks do it badly unless you use the earthed extender lead for the Apple PSU, and then they don’t at all. The standard Apple plug fitting doesn’t connect the mains earth pin for some reason. It bugs me!

PS I’d hoped Apple had fixed this with USB-C charging, but my M3 Pro is even worse than the mid-2012! Really ‘tingly’!

 

[Robert]

Rob Watts gets quite animated on the subject.
All I can say is the sound is superb so perhaps we have to tolerate these niggles and quirks but this was his view on PSUs:

Hugo TT 2 by Chord Electronics - The Official Thread

... Also, something to note: Even when you turn off the TT2 before swapping power, when the power cable is plugged in, the unit automatically powers on. It would be fine except there is a split second where the output stage gets current (you hear a thump on the speakers) and you see the volume...

www.head-fi.org

 

[camverton]

Rob Watts gets quite animated on the subject.
All I can say is the sound is superb so perhaps we have to tolerate these niggles and quirks but this was his view on PSUs:

Hugo TT 2 by Chord Electronics - The Official Thread

... Also, something to note: Even when you turn off the TT2 before swapping power, when the power cable is plugged in, the unit automatically powers on. It would be fine except there is a split second where the output stage gets current (you hear a thump on the speakers) and you see the volume...

www.head-fi.org

Well that’s the bottom line, the sound is superb.

To read some posts over the years you’d think noise was a major problem with Chord products. It isn’t, but that doesn’t mean there isn’t scope for minor improvements. There is with all equipment that has ever been manufactured. That cables with ferrites make a very small improvement to the sound doesn’t mean that the sound was bad before using them, quite the contrary. Let’s face it, in this sort of thread, we are discussing the minutiae of sound quality at a level which wouldn’t even be noticed by the vast majority of music lovers let alone the man on the Clapham omnibus.

 

[llatpoh]

And there was one mod that put that over the top

Out of interest, can you please elaborate?

 

[Justin_P]

Without the external linear supply, it sounded grainy and synthetic to me too. The LPS got rid of the nasties, leaving it much more natural and liquid sounding, but also too relaxed for my tastes. The Denafrips Pontus II has more excitement, but was a bit overexuberant compared to the Qutest. Then the Benchmark DAC2 was more detailed, but too clinical. I didn't strike paydirt until I hit the likes of the Weiss DAC204, Ferrum Wandla+Hypsos and T+A DAC200.

Mike, looking forward to your thoughts on the Wandla with the cornwalls. I have Cornwall iv's too with tubes (primaluna) and looking to upgrade my node x to a better dac.

Your thoughts have been great to read. Have been looking at holo, Weiss, denafrips and the Wandla myself and Maybe t+a 200, but that's pushing the budget. Was worried some of these might be too glaring with the horns. Thanks!

 

[cb01]

Out of interest, can you please elaborate?

RFI Mitigation. I'll do a thread on it eventually.

 

[Mike Hanson]

Mike, looking forward to your thoughts on the Wandla with the cornwalls. I have Cornwall iv's too with tubes (primaluna) and looking to upgrade my node x to a better dac.

Your thoughts have been great to read. Have been looking at holo, Weiss, denafrips and the Wandla myself and Maybe t+a 200, but that's pushing the budget. Was worried some of these might be too glaring with the horns. Thanks!

As you climb the DAC ladder, DACs generally are less "glaring" and more natural. However, the one outlier for me was the Chord Dave. I found it to be rather sharp and edgy to my ears, but I believe it was running standalone (no additional power supply(ies), MScaler, etc.) Most serious Dave owners tend to trick them out with all the outboard help. It also could be the system it was paired with, which was completely new to me.

I'll probably post the my latest DAC observations tomorrow.

 

[martin clark]

the amount of leakage current going into the chassis of the TT2 and Mscaler really should be sorted. One hand on the mains chassis grounded Sugden amp and then lightly touching the Chord product with the other hand givers that finger tingling/static feeling which tells you the PSU leakage is rather higher than it should be in products of this cost.

One of the reasons for such with off-board SMPS is that they all, for reasons of EMC regs - tend to have a small class Y cap, usu c 2.2nF, from output back to Mains side - across the output switch. Makes the emissions graph nice, but injects leakage current.

That's up to 0.1mA of mains leakage current (on UK mains) - harmless but as you say disturbing in terms of 'touch'.

Realise the effect of such a current might have in generating 50/100Hz/harmonic spectrum + intermod voltages across the length of shared-impedance such as single-ended interconnect. In say a 1-5meter of interconnect and all in-series connections inc plugs (say 1-10ohms for all included resistances, for decent-gauge cables... worse for others) well: that utterly ruins the potential SNR and for reasons that have nothing to do with how good the DAC is! At 10ohms for the interconnect, pessimistic but possible for some daft designs, you've just limited the maximal achievable SNR at 3Vac out of the dac to just -69dB (!)

It is also why Toslink is probably best - because then you do not have leakage currents from the DAC's SMPS (any dac) and your laptop's (any laptop/ PC/ NUC) also in contention. It breaks that galvanic path, and for no penalty. Tie the two electrically using USB - who knows what is going on, and no it's not as clean a sound, even with a 'fixed' 5v supply (says a MoJo user since they came out)

tl;dr: no: I am not surprised that even daft-simple linear PSUs can be found beneficial - if so, the principal reason is the typical lack of such large, common-mode mains leakage currents entering the signal path. Yet this will be incredibly context-dependant.


[ETA: line 5 edited to make context clear following @adamdea useful post below on balanced wiring.
NB - there will still be a 'touch voltage apparent!]

 

[Mike Hanson]

One of the reasons for such with off-board SMPS is that they all, for reasons of EMC regs - tend to have a small class Y cap, usu c 2.2nF, from output back to Mains side - across the output switch. Makes the emissions graph nice, but injects leakage current.

That's up to 0.1mA of mains leakage current (on UK mains) - harmless but as you say disturbing in terms of 'touch'.

When you realise the effect of such a current might have in generating 50/100Hz/+, +, + intermod voltages across the length of shared-impedance in say a meter+ of interconnect and all in-series connections inc plugs (say 1-10ohms for all included resistances, for decent-gauge cables... worse for others) - that utterly ruins the potential SNR and for reasons that have nothing to do with how good the DAC is! At 10ohms for the interconnect - pessimistic but possible for some daft designs - you've just limited the maximal achievable SNR at 3Vac out of the dac to just -69dB (!)

It is also why toslink is probably best - because then you do not have leakage currents from the DAC's SMPS (any dac!) and your laptop's (any laptop/ PC/ NUC!) in contention. It breaks that galvanic path, and for no penalty. Tie the two electrically using USB - who knows what is going on, and no -it's not as clean a sound, even with a 'fixed' 5v supply (says a MoJo user since they came out...)

So - no: I am not surprised that even daft-simple linear PSUs can be found beneficial - from their lack of such large common-mode leakage currents. Yet this will be incredibly context-dependant.

The only caveat is the optical S/PDIF interfaces are occasionally included as "checkmarks" in the design. I've encountered multiple devices where the optical option sounded shockingly worse than the coax. Also, S/PDIF interfaces are also typically limited to 192KHz, and often start glitching beyond 96KHz.

If I'm stuck with S/PDIF, then I've experienced the best results with AES/EBU (if available).

However, I prefer to use USB, which supports data rates up to 768KHz. There's the possibility of problems with noisy power wires coming from the source, but an inexpensive Topping HS02 usually nips that in the bud. If it's really bad, one could stretch to a DDC to do USB-to-I²S. There are a many of those available, across a wide range is prices.

 

[Linear]

I had a 2Qute, thought it was a bit bright, a change of interconnect's helped but it was still a bit too shiny for me. I changed it for a Topping, which I thought sounded better.

 

[adamdea]

One of the reasons for such with off-board SMPS is that they all, for reasons of EMC regs - tend to have a small class Y cap, usu c 2.2nF, from output back to Mains side - across the output switch. Makes the emissions graph nice, but injects leakage current.

That's up to 0.1mA of mains leakage current (on UK mains) - harmless but as you say disturbing in terms of 'touch'.

When you realise the effect of such a current might have in generating 50/100Hz/+, +, + intermod voltages across the length of shared-impedance in say a meter+ of interconnect and all in-series connections inc plugs (say 1-10ohms for all included resistances, for decent-gauge cables... worse for others) - that utterly ruins the potential SNR and for reasons that have nothing to do with how good the DAC is! At 10ohms for the interconnect - pessimistic but possible for some daft designs - you've just limited the maximal achievable SNR at 3Vac out of the dac to just -69dB (!)

It is also why toslink is probably best - because then you do not have leakage currents from the DAC's SMPS (any dac!) and your laptop's (any laptop/ PC/ NUC!) in contention. It breaks that galvanic path, and for no penalty. Tie the two electrically using USB - who knows what is going on, and no -it's not as clean a sound, even with a 'fixed' 5v supply (says a MoJo user since they came out...)

So - no: I am not surprised that even daft-simple linear PSUs can be found beneficial - from their lack of such large common-mode leakage currents. Yet this will be incredibly context-dependant.

Am I right in thinking that this is mainly going to be an issue with single ended interconnects as current flowing through the shield of balanced differential cables has a job doing any harm?

 

[Tony L]

I notice some Chord DACs have a phono-stage-like ground terminal on the rear panel, e.g. the 2Qute (eBay), DAC64 (eBay). Is this the reason? My only experience of this is from Macbooks, and there using the longer grounded cable for the Apple PSU adapter stops it.

PS No connection to the auctions, just using some pics from an advertising affiliated source!

 

[martin clark]

Am I right in thinking that this is mainly going to be an issue with single ended interconnects as current flowing through the shield of balanced differential cables has a job doing any harm?

Yes that is correct - but how 'good' balanced interfaces are, is also matter of quite some precision. It's easy to get ...sub-optimal.
Bill Whitlock of Jensen transformers wrote a few interesting things on the latter - rather than waste space here, PM me an email address if its of any interest.

For my own Mojo - I modified a standard 5v wallwart with a bit of copper tape that ties output 0v to mains Earth: that, optical interconnect from macbook pro (used with the earthed extension cable) and no chassic potential differences whatsoever... took five minutes. One of these years I might build an LPSU, but the mojo then has internal smps to boost 5v to 8.4 to charge the battery. and having replaced the battery after 6yrs use - easy diy - there's no significant diff between running off internal battery, and 5v usb supply connected, via headphones anyway...

NB the optical still sounds better / fuller/more refined than usb, but I'm only feeding 44.1Khz/16bit, mostly.

 

[Tim Jones]

My MCRU/Longdog LPSU arrived this morning, and I look forward to testing it with my Qutest when I get home from work.

 

[hifi-dog]

You will like it I’m sure..

 

[Thegreatroberto]

When I had my quietest, I spent too much time trying to hear differences in the filters. A complete waste of my time. Still convinced that just the lamp changed colour and that was it.

 

[camverton]

When I had my quietest, I spent too much time trying to hear differences in the filters. A complete waste of my time. Still convinced that just the lamp changed colour and that was it.

It’s pretty damn subtle isn’t it. Switching between them and comparing the sound I couldn’t hand on heart claim hearing any difference. The funny thing is, however, that in the long term I did prefer one filter over another for listening to music, and it was a different filter when used with different partnering equipment and speakers. Of course the different colours on the filter button have a different effect… Which is annoying because currently I prefer the ”sound” of the white colour but don’t like the look of it!

 

[Tim Jones]

It's a definite improvement, perhaps 10-15% on my Fidelio-Meter. Not entirely night and day, but it certainly takes the slight grain of the cooking SMPS out of the upper registers and makes everything more hear-through.

It's staying.

 

[James Evans]

When I had my quietest, I spent too much time trying to hear differences in the filters. A complete waste of my time. Still convinced that just the lamp changed colour and that was it.

Maybe you should have turned it up a bit

 

[Thegreatroberto]

Maybe you should have turned it up a bit

Haha. I'm sure I did crank it up .