USB to Optical/Spdif

[Liberte]

When using my Mac's USB connection to a Chord Mojo to powered speakers I have a high pitched noise, it seems to be fine when tested with optical outputs, however my Mac has no optical output so I'm looking for an acceptable convertor, if anyone has some suggestions it would be appreciated.

I have tried USB isolators but they do not work and only introduce more noise.

Thanks in advance for any help.

 

[MCH]

Thread 'PHIREE U2S 2019 & Douk Audio U2 Review and Measurements (Digital USB to S/PDIF Interfaces)' https://audiosciencereview.com/foru...ments-digital-usb-to-s-pdif-interfaces.29765/

 

[staticV3]

there's the Hifime S2 Digi, Hifime UT23, and the SMSL PO100, which the brand has since discontinued and replaced with the more expensive PO100 Pro and PO100 AK.
I'd try to find an original PO100 somewhere. It's great

 

[Berwhale]

I have tried USB isolators but they do not work and only introduce more noise.

Which isolators have you tried? Some 'audiophile' ones don't really isolate (i'm looking at you iFi).

A cheap, ADUM4160 chip, isolator like this one worked for me, but it will limit your sample frequency to 96kHz...

https://www.amazon.co.uk/DollaTek-Isolator-Eliminator-Industrial-Protection/dp/B07KXRP784

The Topping HS01 is more expensive, but won't limit you to 96kHz...

https://www.amazon.co.uk/HS01-Isolator-Eliminate-Portable-Suitable/dp/B09LCRCT8T

 

[Liberte]

Thank you so much for the quick replies. I had already found the Douk U2 and great to see it measures well and doesn't cost the earth.

The highest bitrate music I have is 96kHz, I think one 192 kHz album, so some of the other suggestions may be overkill, although don't cost much more for future proofing.

The isolator I tried was the iFi iDefender, powered from a phone charger and also the Vbus2. Thank you for the links, I'm in the UK so should I go the isolation route that is very helpful.

I'm only now unsure whether to try the isolation route again to try and avoid any jitter which may be introduced, if that is an issue, or go with the conversion route. I'm however now somewhat confident I may find a solution to this issue!

 

[MCH]

there's the Hifime S2 Digi, Hifime UT23, and the SMSL PO100, which the brand has since discontinued and replaced with the more expensive PO100 Pro and PO100 AK.
I'd try to find an original PO100 somewhere. It's great

I believe the hifime S2 Digi has an optical input, not output. It is a sort of toslink interface

 

[staticV3]

I believe the hifime S2 Digi has an optical input, not output. It is a sort of toslink interface

 

[MCH]

View attachment 247820
View attachment 247821

Yes, exactly, optical input. What the OP needs is something that has an optical output to feed his mojo dac

 

[staticV3]

Yes, exactly, optical input.

it has both Toslink In and Toslink Out.

 

[MCH]

it has both Toslink In and Toslink Out.

I stand corrected, didn't know that

 

[Tangband]

When using my Mac's USB connection to a Chord Mojo to powered speakers I have a high pitched noise, it seems to be fine when tested with optical outputs, however my Mac has no optical output so I'm looking for an acceptable convertor, if anyone has some suggestions it would be appreciated.

I have tried USB isolators but they do not work and only introduce more noise.

Thanks in advance for any help.

I have a Mac M1 and I have looked around for a good USB bridge and found two - Douk U2 and sky song. The latter sounds slightly better in my opinion . The sound using this with Mac M1 or iPad with Apple lossless is better than from the Yamaha wxc50 playing flac files from a NAS.

https://www.aliexpress.com/item/32899343638.html

Sound review here : https://www.audiosciencereview.com/forum/index.php?threads/bits-are-not-bits-…-or.25101/

Digital out : Yamaha wxc50, skysong , Douk U2 - soundreview.

I have recently done a test in longterm listening with three units used as digital preamps to the digital input of my Genelecs . 1 . Yamaha wxc 50 digital out , spdif , pre amp mode . AirPlay from iPhone with Apple Music lossless. 2. Sky song - a chinese USB bridge with xu208, lt1963...

www.audiosciencereview.com

 

[DonR]

Such a shame Apple removed toslink from their Macs.

 

[Liberte]

Thank you, I find the descriptions of the skysong on Ali a bit confusing, do you use an external power supply with it? There's no clear pictures of the I/O head on and looks like a power connection on the same side as the USB. Edit: I have seen your review and can see it is indeed a power connection.

I will probably try the Topping isolator previously suggested and if that doesn't work the Douk U2, SMSL or sky song convertors.

I'm not sure why apple removed toslink when it was already previously integrated into the 3.5mm port which they still have.

 

[DonR]

I'm not sure why apple removed toslink when it was already previously integrated into the 3.5mm port which they still have.

They saved $0.10 in production costs per unit.

 

[Tangband]

Thank you, I find the descriptions of the skysong on Ali a bit confusing, do you use an external power supply with it? There's no clear pictures of the I/O head on and looks like a power connection on the same side as the USB. Edit: I have seen your review and can see it is indeed a power connection.

I will probably try the Topping isolator previously suggested and if that doesn't work the Douk U2, SMSL or sky song convertors.

I'm not sure why apple removed toslink when it was already previously integrated into the 3.5mm port which they still have.

The skysong can be used with the computer as power supply, or with an external power supply between 5-12 volt.
If using batterys, the resolution in the sound with my SAM monitors take a leap for the better . I have no measurements as evidence , so its my subjective opinion.
The soundquality with skysong driven without batterys is slightly better than using the Douk u2.
Douk u2 is slightly better sounding than Yamaha wxc50 with digital out. Again - my subjective opinion.
Theres small but important differences with these digital transports.

 

[Ken Tajalli]

When using my Mac's USB connection to a Chord Mojo to powered speakers I have a high pitched noise, it seems to be fine when tested with optical outputs, however my Mac has no optical output so I'm looking for an acceptable convertor, if anyone has some suggestions it would be appreciated.

I have tried USB isolators but they do not work and only introduce more noise.

Thanks in advance for any help.

I truly believe either your Mojo has a fault with its USB input chip, or there is a fault with your Mac.
Have you tried the Mojo elsewhere? or possibly another DAC with your Mac? (borrow any dac from a friend).
I did have a Mojo once with a faulty USB chip. Chord repaired it for less than £50 including delivery.
They actually replaced the large chip!
Before spending more money, check it out and contact Chord.
USB decrapifiers won't work in your case, pretty certain.
BTW, max bitrate for optical is 192kHz, and Mojo can take that, provided the cable is decent and the sender can send 192.

 

[Tangband]

When using my Mac's USB connection to a Chord Mojo to powered speakers I have a high pitched noise, it seems to be fine when tested with optical outputs, however my Mac has no optical output so I'm looking for an acceptable convertor, if anyone has some suggestions it would be appreciated.

I have tried USB isolators but they do not work and only introduce more noise.

Thanks in advance for any help.

Might also be problems with groundloops - Using a douk u2 or skysong with toslink out might solve this problem.

 

[Liberte]

Might also be problems with groundloops - Using a douk u2 or skysong with toslink out might solve this problem.

I think it is a groundloop problem which the Mojo is sensitive to, as I only have issues with the Mojo in the middle of Mac and Active Speakers, in every other chain it's OK.

Mac > Mojo > Headphones - Good
Phone > Mojo > Active Speakers- Good
Mac > M-DAC/FC3/Apollo DACs > Active Speakers - Good
Mac > Mojo > Active Speakers - High pitched noise

I did contact Chord but no response unfortunately.

 

[Berwhale]

The isolator I tried was the iFi iDefender, powered from a phone charger and also the Vbus2. Thank you for the links, I'm in the UK so should I go the isolation route that is very helpful.

I bought an iFi Defender and the cheap ADUM4160 one at the same time and tested both. The iFi Defender did nothing so it went back to Amazon

I also solved my ground loop issue by switching to an optical connection (added SPDIF/TosLink bracket to my PC). Eventually I moved to a balanced DAC/Amp (Topping EX5) which fixed the issue for good.

 

[Liberte]

Ha yeah the iFi went straight back, if you're in the UK we probably had the same one!

My balanced DAC (M-DAC) is also fine, although I can use the RCA outs with no issues either.

I feel pretty confident the USB to optical is going to help so have a Douk U2 on the way from China. I will however test the Mojo via USB with my Windows PC when I'm home out of curiosity to see if it also has the high pitched squeal listening through the active speakers.