[iFi audio]

I think you are experiencing a grounding problem. I resolved buying a ifi groundhog

Yup, Groundhog was designed to provide ground and am happy that it did the job for you

 

[dac64]

I have two primary amps on my desk that I like to alternate between.

I'm trying to figure out a simple way, that won't degrade the sound, to get the signal to both amps.

Y-Split

 

[MWeston]

Just a tip. The Qutest and your headphones are a class above the S.M.S.L. I suspect you have a lot to gain by upgrading that headphone amplifier.

Haha, yes I knew a comment like this might come up. The SP200 does a decent job but I am working on a new amp for my headphones. It's on the roadmap for sure! I'd like something with a touch warmer sound. The A90 looks nice but we'll see. That amp will have the same ground loop issues from what I've read so I have to solve this issue first.

 

[ra990]

Haha, yes I knew a comment like this might come up. The SP200 does a decent job but I am working on a new amp for my headphones. It's on the roadmap for sure! I'd like something with a touch warmer sound. The A90 looks nice but we'll see. That amp will have the same ground loop issues from what I've read so I have to solve this issue first.

The SP200 is actually a cool pairing with the Qutest. It's a similar size, easily stackable, very quiet, powerful, and it's a single ended amp for a single ended source. I use it on my bedside setup at times.

 

[Hooster]

Haha, yes I knew a comment like this might come up. The SP200 does a decent job but I am working on a new amp for my headphones. It's on the roadmap for sure! I'd like something with a touch warmer sound. The A90 looks nice but we'll see. That amp will have the same ground loop issues from what I've read so I have to solve this issue first.

Something from Violectric or SPL might be worth considering too. The best of luck.

 

[DecentLevi]

Hey all,

I've had a major disappointment tonight. I'm using the Qutest through a S.M.S.L. SP200 amp and then into my Sony MDR-Z1R's. They are pretty sensitive and at the end of a song, I noticed a little bit of static when nothing was playing. I cranked the amp full (with no music playing) and the noise was terrible plus it was making lots of morse code-like sounds at me; just bleeping and blooping away at me.

I disconnected the USB from the computer...no change. (not a USB issue)
I disconnected the RCA jacks from the Qutest but left the 1m lengths hanging out of the amp...noise all gone. (not an RCA noise coupling issue based on wire length)
I use surge protection/battery backup (pure sine output) so I moved the power adapter straight to the wall...noisy.

So this noise is being generated internally to the Qutest and the remaining noise input is the power supply adapter. Are other people seeing this? If so, did you find a way to solve it? This thing is way too expensive to sound like an old AM radio between songs, not cool at all!

Is the solution for me to run a ground wire from the chassis of the Qutest to the earth ground of my home? I don't even think this old place is even providing earth grounding in the outlet box.


Thanks!

I would say the sound you describe would unmistakably be either from a cell phone or Wi-Fi router; probably the former; both of which are very detrimental to the audiophile hobby that people spend a lot of money getting rid of such RF or HF interference. Try turning off one or both and see it that solves the problem. If so, consider further moving away either cell phone or Wi-Fi router, or getting shorter or better shielded RCA cables would be my advice.

 

[Triode User]

I would say the sound you describe would unmistakably be either from a cell phone or Wi-Fi router; probably the former; both of which are very detrimental to the audiophile hobby that people spend a lot of money getting rid of such RF or HF interference. Try turning off one or both and see it that solves the problem. If so, consider further moving away either cell phone or Wi-Fi router, or getting shorter or better shielded RCA cables would be my advice.

Agreed and that would be my first thought of what is causing the noise. I have also had a 'wifi power thingy repeater that plugs in the mains to send the signal' make the same noise through a DAC placed too close. @MWeston I would suggest looking at all your wiring routing and any nearby Router, DECT phone, wifi repeater etc.

 

[DecentLevi]

So then, in thinking about how much of a difference clean DC power from an LPS makes to the Qutest, it's had me wondering how the chosen digital input may be coloring the sound (in my case BNC coax cable from my DI-20 audio interface AKA DDC). Is there any merit to the notion that a BNC connection may introduce any impurities in the signal to the Qutest? Granted it's not carrying a power signal in the same way as DC power but it's got to be carrying some sort of current or voltage.

If so, would anyone recommend a sort of isolator or galvanic device for digital coax connections that would further improve things? And what product might that be? I've already looked at the iFi Groundhog, but that seems to serve a different purpose. I'm getting fantastic sound nevertheless, but just curious about possible tweaks.

 

[blueninjasix]

Try a different optical cable, even the cheapest one. If it plays, then your cable is not suitable for such a high flow.

And my understanding is that Chord have changed their blurb to now say the limit for optical is 96khz and not 192khz as previously stated even in the Qutest manual.

 

[Flognuts]

How does this compare to the mojo as a desktop dac?
I am seriously impressed with the mojo's dac so wondering how different this sounds

 

[nxxo]

It sure does have the signs of a ground loop. I'll see if my other DAC does this because it has a similar power setup (power brick, no USB power). Testing with a battery pack might be a good way to see if it goes away, but it's definitely not the solution to my problem. This is a purely desktop setup so I must solve this in a more permanent way.

Edit: My other DAC does the same thing. The loop is happening when the signals get into the amp which has an internal switching supply and, likely, isolated ground from the mains. I guess this is the argument for an all balanced system!

Looking at ifi ground hog is not very expensive and it might be a good idea in your situation.

 

[DecentLevi]

I'm using a medium quality BNC cable with from my DDC to the Qutest, the Belden 1694A from BlueJeans cable for $25, and will soon be getting an industry-leading one from Wave High Fidelity - will chime in on any differences.

 

[uzi2]

Although this was in answer to the use of BNC cables with M Scaler, Rob Watts comments are very interesting. I was surprised that a longer cable (2M) would produce better sound than a shorter one, but ferrites appear to be the way to go and are included with the Wave cables.

 

[snatex]

Try a different optical cable, even the cheapest one. If it plays, then your cable is not suitable for such a high flow.

I tried a cheaper Fospower cable today and that didn't work either. Instead of the faint static I got from the Lifatec, the Fospower played nothing.

I confirmed my Mac Mini 2014 plays 192khz and my Audio Midi settings were correct.

I noticed that the light in the middle of the Qutest that turns green when playing 96hz flashes red when I switch to 192khz. Does that flashing red light indicate anything?

 

[uzi2]

I regularly swap the Qutest from desktop to main system. I have just built a new PC around a Gigabyte Aorus Elite AC motherboard and USB to Qutest is really clean. I think the modern motherboard designs are doing really well to reduce noise to audio systems. I am running HQplayer, so 705/768k to Qutest. The desktop system uses the stock power supply with no issues. The main system is fed via RPi4 NAA and both Pi and Qutest are powered by Shanti. I am more persuaded that it is the Pi that needs the linear power supply more than the Qutest
Edit : I should add that I am using a Corsair RW750x power supply for the computer