USB isolator for Mac Mini to Chord Hugo

I've got the same Mac and a Hugo, and have a USB Regen on the Hugo end and a Jitterbug on the Mac end of the USB cable.  Both made a difference, as did the USB cable, but the USB Regen made the biggest difference.  Unlike some other devices you can still play high res material with this set up and it sounds superb 

There's also a newer device called the Intona High Speed USB isolator. This gives you galvanic isolation and (unlike other similar devices) allows all USB 2.0 speeds so you can use it in the HD I out of your Hugo and play high res material. I think you'll find that Rob Watt said that he "can't see any reason why it shouldn't work - looks like an interesting and useful device." I don't think the USB Regen or the Jitterbug give galvanic isolation.

Galvanic isolation simply is a method of preventing earth or ground plan loops and reducing resultant common mode noise as well as  decoupling the DC element from the signal. Galvanic isolation will have little if any effect on RF  noise from the USB transmission itself and poor impedance matching.

The USB regen for example rebuilds the USB balanced serial lines from what I can gather and decouples the power line wires in the USB cable and therefore it appears it effectively provides galvanic isolation.  Without galvanic isolation there is a possibility that you may get earth loops and a resultant hum from the audio output depending on what USB source you use and what you connect the USB DAC to. A galvanic isolator will prevent this hum.

https://en.wikipedia.org/wiki/Galvanic_isolation

The Jitterbug is an easy one to try and send back if you don't like what it does. The Regen is great and i found it worked well when i was running a Mini / Audivarna front end. I use an Intona USB isolator with my present setup which is available on sale or return so it's little risk giving it a go. 

amirm has produced some interesting measurement of both the regen and the jitterbug over on the whatsbestforum. Essentially he concluded that they both make things slightly worse - there is certainly no measurable noise reduction. Nor it seems could the designers of the devices produce any measurements to justify their claims.

To be honest - these things are cheap tweaks to try and easy to send back, sell on if you don't like. Too much crap and hidden agendas in some of those places you mention Likesmusic...

likesmusic posted:

amirm has produced some interesting measurement of both the regen and the jitterbug over on the whatsbestforum. Essentially he concluded that they both make things slightly worse - there is certainly no measurable noise reduction. Nor it seems could the designers of the devices produce any measurements to justify their claims.

I'm much more interested in what I can hear than in what someone says they can measure on some system that isn't mine.  When I first started out in hifi the prevailing wisdom was that speaker wire could have no impact on sound that could be measured.  They were wrong too.  Trust your ears, you know them better than Amirm I suspect, and send back anything you can't hear give an improvement on your own system.  I rarely choose a hifi component or an album based on its measurements - although I do choose my shirts that way

Thank you all for your responses so far. The topic of isolation, jitter and the like seems to be not so clear-cut, though it is encouraging that many of these devices have the option to return if unsatisfying. 

In terms of "do I need galvanic isolation", is it as simple as "I do not hear a background hum, therefore I do not need galvanic isolation"? I certainly do not hear any hum.

When first setting up my Mac Mini with the Hugo earlier this year, I did try some A-B comparisons between the Mac Mini optical output and the USB output, and I couldn't hear any differences. I was using my PSB M4U 2 headphones. My Mac Mini is loaded exclusively with ripped CDs.  

I also couldn't really detect any differences between ripped CDs on the Mac Mini (via USB) and my old Marantz CD67SE CD player playing the same disc into the Hugo via coaxial cable.

Having read many of the discussions on the best Hugo inputs, I'm wondering if my system or my ears are not sufficiently resolving to pick up the differences some of the more owl-eared forumites detect!

Flumpet posted:

When first setting up my Mac Mini with the Hugo earlier this year, I did try some A-B comparisons between the Mac Mini optical output and the USB output, and I couldn't hear any differences. I was using my PSB M4U 2 headphones. My Mac Mini is loaded exclusively with ripped CDs.  

I also couldn't really detect any differences between ripped CDs on the Mac Mini (via USB) and my old Marantz CD67SE CD player playing the same disc into the Hugo via coaxial cable.

Having read many of the discussions on the best Hugo inputs, I'm wondering if my system or my ears are not sufficiently resolving to pick up the differences some of the more owl-eared forumites detect!

I'm not sure that noise cancelling headphones are the best way to make these comparisons. I haven't heard your PSBs, so this is partly speculation, but if they're anything like the Bose QCs they may not be resolving enough to show up the differences you're listening out for. 

Also, are your CD rips up to scratch?

Thank you. My headphones have 3 settings: passive, active and noise-cancelling. Passive sounds flat and muddy, whilst the noise-cancelling setting sounds brighter but a little artificial. So I tend to use the active setting. They are probably not the last word in headphones, but they were a clear winner for my tastes versus the other headphones (Sennheiser Momentum, Musical Fidelity something) in the shop (Audio T, Cheltenham). 

The PSBs are considered by some to have inferior noise-cancelling capabilities compared to Bose, but superior music replay. Are active headphones generally thought of as not sufficiently 'hi-fi'?  

I'm more confident about the rips. They were done using dbPoweramp with my CD drives fully configured, and they are Accurate Rips.

My impression is that noise cancelling headphones are generally considered to have rather average sound quality, and I seem to recall the odd post on this forum to that effect. My own experience, though, is limited to Bose, which were great for long-haul flights, but didn't really make me want to listen to music. Maybe I'm underestimating your PSBs; I don't know?

Re. CD rips,it sounds like you've got that sorted - just checking that you weren't using some nasty lossy MP3s or something!

Re OP, i use a Gustard U12 USB/SPDIF isolator/convertor. Bought last summer from a well known auction site for about £110 (new), also available from an online former bookstore for a tad more. Very happy with it: without it Mac Mini -Audirvana into Hugo was distinctly mediocre, poorer than ND5XS into Hugo (and poorer than ND5XS alone). The isolator/convertor lifted the veil and it sounded better than ND5XS into Hugo, enabling retirement of the ND5XS (XP5XS already having been retired in favour of the improvement Hugo gave for less money).

I solved the galvanic isolation issue with my Hugo by changing it to a Hugo TT. And very good it is too! 

is the TT worth the cost of two Hugos +isolators?

Innocent Bystander, I've heard a lot of good things about the Gustard, and the coaxial input on the Hugo in general. Unfortunately the coaxial connection to my Hugo always drops out which a light or electrical socket is switched in the near vicinity. I live in an apartment in Switzerland.

I've tested this with CD player into the Hugo and with the TV optical output converted to coaxial (via a cheap convertor) into the Hugo. In both instances drop-outs occur. 

However, when I change to a cheapo DAC these problems no longer occur. I have also tried the Hugo with two different coaxial cables, and with unplugging the power supply so it is running on batteries only. In all instances the drop-outs occur. 

Any ideas what the reason might be?

Likesmusic, did you part-exchange your Hugo for a Hugo TT? If so, may I ask if you recouped much of your Hugo costs? I could maybe stretch to a TT, but only if I could get a good price for my Hugo.

You might want to try a better SPDIF cable, and is your CD player (feeding your Hugo) galvanically isolated? 

It sounds like you are picking up noise in your SPDIF transport 

The coax cable is a QED Performance. I have no idea how to find our or test the galvanic isolation of the Cd player. It is a Marantz CD67SE purchased in 1998! 

I'll try to repeat some of these tests soon, but so far the only common denominator I can see in the problem is the Hugo itself. And my apartment block (I've moved up one floor since getting the Hugo, amd the problem remains).

I would just use the optical out from the mac to the Hugo.

Rob watts says the optical out is the best sounding input anyway, and the hugo reclocks and buffers the signal.

I use the squeezebox touch optical out, which is by default galvanically isolated, and it sounds just fine to me.

No need to upgrade to a Hugo TT and saved me lot of money buying an alternate streamer, which may not, in the end sounds as good as the squeezebox.

Any streamer with an optical output would do the job with a Hugo/Mojo/TT/2qute, as they all reclock the signal, in my humble opinion, but YMMV.

Any differences in hearing streamers with the Hugo, in my humble view is due to using USB or Coax inputs. There of course there is no galvanic isolation, so electrical signals can influence the sound of the Hugo as it is not decoupled electrically.

I am sure I will be contradicted on this, so feel free to do so, but I am only saying what Rob Watts advises, use the optical for best sound quality on the Hugo.

Thank you. I will try to have an extended listen to the optical input from the Mac Mini.

My preference was to keep the optical input on the Hugo free for the TV so we can use the hi-fi for films as well. The TV only has an optical output. 

I could have both the TV and Mac Mini optical connections going to the Hugo if I use a 2:1 optical switchbox (the company Cyp makes one for a modest sum). If the Hugo reclocks the signal anyway, is there any danger in using a modest switching device before the Hugo? Are there other ways that the music signal could get compromised with such a device?

Flumpet posted:

Likesmusic, did you part-exchange your Hugo for a Hugo TT? If so, may I ask if you recouped much of your Hugo costs? I could maybe stretch to a TT, but only if I could get a good price for my Hugo.

Yep, I did a p/x with the original dealer and got a pretty fair price. I got the TT on trial really just to satisfy my curiosity and fully expected to return it. But the improvement over the plain Hugo was much more than I expected, so I kept it. Some of the improvement may be down to the fact that I have active speakers, so the balanced outputs of the TT have an advantage, and some may be down to the fact that I like to use JRiver on a fanless laptop via USB for some of my listening, so that galvanically isolated USB input would be beneficial, but comparing s/pdif via optical from my Squeezebox Touch using Sennheiser HD650 headphones there was still a pretty decent difference, so there's more to the difference than just balanced outputs or galvanically isolated USB. It's just a more solid, tangible, musical experience, I just get so lost and moved by and involved in and enriched by my music, it's something very special and precious to me. 

All though into a resolving system I have yet to hear optical sound as good as electrical SPDIF into the Hugo. If you use a good quality isolated transport then go SPDIF. If the quality of the transport is mediocre to poor or is not isolated go optical.

i use a NDX with a choked 75ohm cable with BNC to phono to feed my Hugo.. and it works!! That is the transport that gives me that goose bump inducing  inner presence to the sound that makes the Hugo the incredible DAC it is. None of my optical transports achieve this, although they sound very good they don't show off what the Hugo is truly capable off... and at that level there are probably lots of other cheaper DACs to choose from.

I once did use Vertere Acoustics D-Fi V2 USB cable into Hugo (with a WinPC setup/Foobar) but did not try any USB isolator. I then switched to Mac Mini (Late 2014) end of last year, but did run into the USB bug that came with early OS X El Capitan, causing stops, distortion of playback.

I bought Wireworld Supernova 7 optical cable which unfortunately did not fit 100% into Hugo.

With such a “loose connection” I did expect no sound at all, but strangely could play up to 24bit/96kHz. I noticed immediate improvement compared to USB connection and connection with by packed standard plastic toslink cable, so kept this setup.

Some months later, I swapped to Hugo TT and Wireworld Supernova 7 now fits perfectly. With OS X El Capitan 10.11.4 update the USB bug was solved in the meantime but there are currently no plans for me to think about going back to USB (as I don’t need playback for anything higher than 24/192 or DSD64).

I'm not convinced that optical is the best way to link Mac Mini and Hugo: when I first set up MM and Audirvana, pre Gustard isolator/convertor, I found an optical connection better than USB, however using the Gustard U12 between USB MM output and Hugo electrical SPDIF input sounds better. This is consistent with what Damian Plisson, Audirvana's developer, says in his paper Beyond bit-perfect: The importance of the Player Software And MAC OS X Playback Integer Mode :

"First way to connect to the DAC is to use the build-in TOSLINK output of the Mac. But this one should be dismissed for being too jittery for serious use. Strong improvement comes by using “computer connection” to the DAC, being either USB or FireWire."

As for the dropout problem experienced with Hugo's electrical SPDIF input, I haven't anything to offer - I certainly don't have a problem, and if It does it when Hugo is running on battery with power supply disconnected the influence of mains interference could only be on the digital source(s), maybe injecting some noise that overloads the Hugo's input (wild guess). If that is the case, an isolator between those sources and Hugo may do the trick for them as well as Mac Mini. Either way, the Gustard U12 has optical output as well as electrical SPDIF, so could connect to Hugo that way, though I haven't  tried myself (yet)

There are so many variables - it's possibly unwise to make categorical statements. After all, who has tested every pc or mac or s/pdif device with a Hugo. Mr W himself prefers the sound of USB into a DAVE, but even he has just discovered his humungous Windows 10 computer sounds better running from batteries than mains so even he hasn't sorted all the issues or got all the answers.