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Topping D90 Balanced USB DAC Review

hmscott

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I go farther in my setup, using an audio isolation transformer on the balanced outs of my DAC to the inputs of the preamp.
What is the isolation transformer product info? Link?

What improvement does it provide beyond the XLR connection between the DAC and AMP? Do you not have balanced inputs on the preamp?

Speaking of isolation transformers, I also added inexpensive AC power filtering on the D90 MQA / A90 which reduced the noise on the RCA audio, I'd also like to add one of my Tripp Lite AC power isolation transformers from storage - someday.

Before re-cabling and power filtering the RCA line noise was audible on L Gain, it took a several stage approach to solve the noise problem for RCA - power filtering, shielded RCA cables, shielded USB cable with RFI / EMI reducing ferrite cores built-in, and now I'm trying to remove the last of the USB induced noise by using an improved USB output from the PC or a USB isolator / converter.
That's a great illustration of how valuable balanced connections can be.
Unfortunately we don't always have XLR balanced connections available on inexpensive or small portable consumer DAC's, or related equipment in the audio chain.

The D90 MQA isn't "inexpensive" at $700 so including XLR connections is "standard", and I'd like to see USB signal isolation and galvanic power isolation "standard" in this price class of DAC's.

The D90 MQA only has two outputs, one balanced XLR and one unbalanced RCA, so if you need more than one audio stream from the D90 MQA you still need to use the RCA output.

Removing the RCA connections, stopping the GPU birdies and other noise riding on the RCA connection improved the audio... I'm listening to the same tracks with KZ ZAX's.
https://tidal.com/browse/album/107167238
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https://einsteinathome.org/content/latest-einsteinhome-discovery
 
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MakeMineVinyl

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What is the isolation transformer product info? Link?

What improvement does it provide beyond the XLR connection between the DAC and AMP? Do you not have balanced inputs on the preamp?

https://www.parts-express.com/jensen-jt-11p-1-premium-line-input-transformer-1-1--246-0103

This might be a bit more DIY than you want. The main reason I went this route is my system is very complex and I needed to break the possibility of ground loops, especially since some of my gear is routed through a patch bay. Transformers offer absolute isolation which electronically balanced inputs/outputs cannot.

My preamp is unbalanced in, vacuum tube, my own design.
 

Dclone

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Thank you, I had hoped you had used some other converters you could suggest too. I've seen quite a few, but noticed the Singxer version is much less expensive than the Kitsune "tuned" version, which from the open top looks the same - except for a "different" USB connector.

There is still the consideration of the I2S "compatibility" with the D90 / D90 MQA which is why I included the link and spoiler with text concerning that to see how the D90's might be compatible. If you get a chance to check out the notes please let us know what you think, will it be compatible with the D90's?

I do still get the GPU noise faintly under certain setup parameters - rare but it's there. So I'm still working to find a solution - hopefully one that isn't $400-$700+ to solve.

I see ifi has some USB isolation and power noise mitigations built into their DAC's, perhaps something to consider for a future Topping DAC feature set? :)

Have You tried another USB cable? Solved noise problem for me. I use Supra midprice cable and my system is totally quiet after cable change
 

hmscott

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https://www.parts-express.com/jensen-jt-11p-1-premium-line-input-transformer-1-1--246-0103

This might be a bit more DIY than you want. The main reason I went this route is my system is very complex and I needed to break the possibility of ground loops, especially since some of my gear is routed through a patch bay. Transformers offer absolute isolation which electronically balanced inputs/outputs cannot.

My preamp is unbalanced in, vacuum tube, my own design.
Thank you, that's awesome. That product page had a link to "Jensen JT-11P-1 Project Design Schematics" that referred to a consumer product I had actually already looked at: the Jensen consumer boxed up version with 2 of these isolation transformers:
https://www.jensen-transformers.com/product/ci-2rr
1603905387715.png
Balanced to unbalanced:
https://www.jensen-transformers.com/product/pc-2xr/
https://www.parts-express.com/jense...-high-to-low-level-signal-converter--246-0127
1603912051780.png
I also noted the design guidelines recommend a short connection between the audio source and transformer vs target device, and to isolate the transformer case from the car ground. ifi's DAC's do a good job of isolating components and grounds internally so as to not get stray currents inducing noise or creating ground loops.

Especially for Topping that provides both the DAC and Headphone AMP I would hope they would work out the stray current paths from RCA / XLR across their devices. Perhaps Topping will pay more attention to these considerations in the next products.
 
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hmscott

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Have You tried another USB cable? Solved noise problem for me. I use Supra midprice cable and my system is totally quiet after cable change
Sounds interesting, link? Product / model details?

What kind of noise did it get rid of? General PC internals induced USB Hash noises? Hissing / crackling USB powerline noises?, or GPU birdies?
 
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Dclone

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Sounds interesting, link? Product / model details?

What kind of noise did it get rid of? General PC internals induced USB Hash noises? Hissing / crackling USB powerline noises?, or GPU birdies?

All noises sent away immediately and there were lots of them... Pops, clicks, cpu, hissing sounds etc. I use the 10 meter cable. I even use those cables for my DSPs. Here is the link
http://www.jenving.com/products/view/usb-2.0-a-b-1001908381
Good luck!
 

bogi

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Supra cables have all wires separately shielded and therefore EMI from VBUS and ground power lines does not pollute data wires. That's the trick. And also the precise 90 Ohm impedance match. These cables are not expensive, when looking how they are done.
 

hmscott

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Supra cables have all wires separately shielded and therefore EMI from VBUS and ground power lines does not pollute data wires. That's the trick. And also the precise 90 Ohm impedance match. These cables are not expensive, when looking how they are done.
All noises sent away immediately and there were lots of them... Pops, clicks, cpu, hissing sounds etc. I use the 10 meter cable. I even use those cables for my DSPs. Here is the link
http://www.jenving.com/products/view/usb-2.0-a-b-1001908381
Good luck!
Thank you both!, I've had these recommended to me before but I can't find them to purchase - Amazon is always out of stock, where did you purchase the Supra Cable? :)

Supra 0.7 Meter USB 2.0 Cable - Type A to B
https://www.amazon.com/Supra-0-7-Meter-USB-Cable/dp/B00GTSSJZK

You gave me the source site, Jenving Technology, and following their distributors list to the USA distributor and that points back to the manufacturers home site, under Purchase they say Ebay...

Okay, found it:
https://www.ebay.com/itm/Supra-USB-...I-FI-5-STAR-RATED-Made-In-Sweden/154018467773

Thanks again :)
I've used ferrite clip-on filters with success in the past when I've run into noise on USB and Firewire. Amazon has them.
Hi, back again, it looks like I should pick up a box of these in varying sizes to clip to USB cables without ferrite cores. Which "clip on" Ferrite cores are effective? I've heard that some are "fake" or ineffective, which product / model did you find were effective for you? Link(s)? Thank you :)
 
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Atanasi

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No, USB is not always *best* to use, not if the source lays a barrage of noise induced on the USB power and data lines.
I think a USB-optical bridge makes sense for galvanic isolation, they are not expensive.
For USB, one can use a USB isolator like Intona if there is a problem with stray currents. I like the idea of USB isolators, because they can be used for multiple purposes: they are not restricted to audio and for audio applications, they can be moved from one device to another.
 
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MakeMineVinyl

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Hi, back again, it looks like I should pick up a box of these in varying sizes to clip to USB cables without ferrite cores. Which "clip on" Ferrite cores are effective? I've heard that some are "fake" or ineffective, which product / model did you find were effective for you? Link(s)? Thank you :)

Honestly, I just used some I had in my parts box, so I don't know what spec they would have. I did have to use a couple on one cable to supress the noise, and in a couple instances they didn't do much at all. I did put a couple on the AC wires coming from a light dimmer which reduced the buzz bleeding through my electronics.
 

hmscott

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Honestly, I just used some I had in my parts box, so I don't know what spec they would have. I did have to use a couple on one cable to suppress the noise, and in a couple instances they didn't do much at all. I did put a couple on the AC wires coming from a light dimmer which reduced the buzz bleeding through my electronics.
Thank you, I've have similar in storage - not the right size and probably old enough that I shouldn't rely on them - I used them around the house on various phone, data, cables looped several times around the core as each successive turn reduced the RF successfully for mitigating stray RF from Ham Radio transceivers. I'll dig into current Ham reviews and articles to find good parts that have proven to work.

I did message the ebay seller for the 0.7m Supra cable, here is the exchange:
"Hi, I've got issues with USB powerline and dataline noise from my PC making it in to my Topping D90 DAC and via RCA connection to my Topping A90 Headphone amp I am getting GPU noise, USB hash noise, and power noise. Using an inexpensive Tripp Lite USB A-B cable with Ferrite Cores on each end I've gotten rid of most of the noise, but I've been recommended to switch to your cable to reduce noise further, but you don't have Ferrite Cores on the ends of your cables - can you add them? I need to keep out RFI and EMI noise as well as PC noise. If you don't build in the Ferrite Cores can you point out to me "clip on" ferrite cores that work? - Thank you!, Scott "

"Greetings, Scott:
Unfortunately, we can't offer the cable with ferrite cores. But - really - the Supras will remove your difficulties. Just try them!"
So I'll look for ferrite cores and order the Supra cable and see how it compares.

Thanks to all for your suggestions :)
I think a USB-optical bridge makes sense for galvanic isolation, they are not expensive.
For USB, one can use a USB isolator like Intona if there is a problem with stray currents. I like the idea of USB isolators, because they can be used for multiple purposes: they are not restricted to audio and for audio applications, they can be moved for a device to another.
Thanks for the suggestion, it looks like Intona has a number of models:
https://intona.eu/en/products/

And, there's a review of USB isolators here on ASR that includes a positive result for the Intona:
https://www.audiosciencereview.com/...s-of-intona-usb-isolator-for-audio-dacs.2616/

Intona section of Conclusion:
"It is in this context that I smile when I see the performance of the Intona USB Isolator. Finally a USB filter that actually filters! So congratulations to Intona for building a proper product that reproduces the USB bus cleanly.

Alas, as I have shown with RME ADI-2 DAC, you do not need USB filters. The solution to Modi 2 Uber noise and distortion is to buy a DAC at the same price or lower that doesn't have these issues. Schiit products seem to be sensitive to quality of USB power. Better designed DACs don't have that problem."

It will take more research to figure out which to get for my specific USB noise problems, I'll email them and ask. But, initially my first thought is, the USB isolators don't cost much (any?) less than the USB Converter Isolators I've seen, which works best at lowest cost is something I'll have to find out.

For now the short Supra USB cable is an inexpensive positive next step. I didn't follow through on trying it due to the lack of feedback I found on USB noise - I only found audio quality comparisons and while positive I didn't see how it applied to my USB noise problems. Hopefully the power / data shielding and isolation will help reduce the noise, but I still think the GPU noise will come through. It will be interesting to find out.
 
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hmscott

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Thank you, that's awesome. That product page had a link to "Jensen JT-11P-1 Project Design Schematics" that referred to a consumer product I had actually already looked at: the Jensen consumer boxed up version with 2 of these isolation transformers:
https://www.jensen-transformers.com/product/ci-2rr
View attachment 90030
Balanced to unbalanced:
https://www.jensen-transformers.com/product/pc-2xr/
https://www.parts-express.com/jense...-high-to-low-level-signal-converter--246-0127
View attachment 90052
I also noted the design guidelines recommend a short connection between the audio source and transformer vs target device, and to isolate the transformer case from the car ground. ifi's DAC's do a good job of isolating components and grounds internally so as to not get stray currents inducing noise or creating ground loops.

Especially for Topping that provides both the DAC and Headphone AMP I would hope they would work out the stray current paths from RCA / XLR across their devices. Perhaps Topping will pay more attention to these considerations in the next products.
@MakeMineVinyl - I found an interesting paper written by Bill Whitlock of Jensen Transformers, I thought you might be interested - or have already seen it :)

UNDERSTANDING, FINDING, & ELIMINATING GROUND LOOPS
CEDIA Class EST016
Instructor Bill Whitlock President & Chief Engineer
Jensen Transformers, Inc. Chatsworth, CA
https://web.mit.edu/jhawk/tmp/p/EST016_Ground_Loops_handout.pdf

Some sections of Particular interest: All of it, all the way to the end + references. :)
 

Dclone

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Thank you, I've have similar in storage - not the right size and probably old enough that I shouldn't rely on them - I used them around the house on various phone, data, cables looped several times around the core as each successive turn reduced the RF successfully for mitigating stray RF from Ham Radio transceivers. I'll dig into current Ham reviews and articles to find good parts that have proven to work.

I did message the ebay seller for the 0.7m Supra cable, here is the exchange:
"Hi, I've got issues with USB powerline and dataline noise from my PC making it in to my Topping D90 DAC and via RCA connection to my Topping A90 Headphone amp I am getting GPU noise, USB hash noise, and power noise. Using an inexpensive Tripp Lite USB A-B cable with Ferrite Cores on each end I've gotten rid of most of the noise, but I've been recommended to switch to your cable to reduce noise further, but you don't have Ferrite Cores on the ends of your cables - can you add them? I need to keep out RFI and EMI noise as well as PC noise. If you don't build in the Ferrite Cores can you point out to me "clip on" ferrite cores that work? - Thank you!, Scott "

"Greetings, Scott:
Unfortunately, we can't offer the cable with ferrite cores. But - really - the Supras will remove your difficulties. Just try them!"
So I'll look for ferrite cores and order the Supra cable and see how it compares.

Thanks to all for your suggestions :)

Thanks for the suggestion, it looks like Intona has a number of models:
https://intona.eu/en/products/

And, there's a review of USB isolators here on ASR that includes a positive result for the Intona:
https://www.audiosciencereview.com/...s-of-intona-usb-isolator-for-audio-dacs.2616/

Intona section of Conclusion:
"It is in this context that I smile when I see the performance of the Intona USB Isolator. Finally a USB filter that actually filters! So congratulations to Intona for building a proper product that reproduces the USB bus cleanly.

Alas, as I have shown with RME ADI-2 DAC, you do not need USB filters. The solution to Modi 2 Uber noise and distortion is to buy a DAC at the same price or lower that doesn't have these issues. Schiit products seem to be sensitive to quality of USB power. Better designed DACs don't have that problem."

It will take more research to figure out which to get for my specific USB noise problems, I'll email them and ask. But, initially my first thought is, the USB isolators don't cost much (any?) less than the USB Converter Isolators I've seen, which works best at lowest cost is something I'll have to find out.

For now the short Supra USB cable is an inexpensive positive next step. I didn't follow through on trying it due to the lack of feedback I found on USB noise - I only found audio quality comparisons and while positive I didn't see how it applied to my USB noise problems. Hopefully the power / data shielding and isolation will help reduce the noise, but I still think the GPU noise will come through. It will be interesting to find out.

I can confirm that, in my setup, every kind of noise even USB noise disappeared totally with the change of cable to Supra. Reason why I chosed Supra is that it was the only cable available in 10 meter. I can now plug/unplug the cable to/from the system on without any pops, clicks or noice
 

hmscott

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I can confirm that, in my setup, every kind of noise even USB noise disappeared totally with the change of cable to Supra. Reason why I chosed Supra is that it was the only cable available in 10 meter. I can now plug/unplug the cable to/from the system on without any pops, clicks or noise
That's great, I sure hope my new Supra 0.7m USB cable has the same effect on my USB noise. It's estimated to be delivered Monday, I'll report how it works next week after it arrives. :)
 
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Atanasi

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It will take more research to figure out which to get for my specific USB noise problems, I'll email them and ask. But, initially my first thought is, the USB isolators don't cost much (any?) less than the USB Converter Isolators I've seen, which works best at lowest cost is something I'll have to find out.
There is one point about Intona, and probably other isolators. Many XMOS-based products like Topping DACs are not fully USB-compliant and have problems with isolators. Inserting the device doesn't always initialize it correctly.
I have tried Intona 7055-C with Topping E30. Initialization problems were fixed by adding a bus-powered USB hub downstream from Intona, and changing the cable upstream from Intona to a shorter, 1 meter cable.

MOTU M4 is also based on XMOS and required a similar chain, except that the cable upstream from Intona had to be USB 3 to get enough power, or a self-powered hub had to be used downstream from Intona. MOTU M4 is bus-powered and requires 500 mA.

I have heard XMOS-issues can be fixed through firmware upgrades. I hope Topping would release fixes for their products.
 

Veri

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There is one point about Intona, and probably other isolators. Many XMOS-based products like Topping DACs are not fully USB-compliant and have problems with isolators. Inserting the device doesn't always initialize it correctly.
I have tried Intona 7055-C with Topping E30. Initialization problems were fixed by adding a bus-powered USB hub downstream from Intona
You realise the Intona also uses some power and feeds remaining to the isolated device? If you need a bus-powered USB hub downstream from Intona, it simply means the Intona by itself feeds insufficient power.

From Intona:
  • 300mA nominal output current on isolated side
 

Atanasi

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You realise the Intona also uses some power and feeds remaining to the isolated device? If you need a bus-powered USB hub downstream from Intona, it simply means the Intona by itself feeds insufficient power.

From Intona:
  • 300mA nominal output current on isolated side
7055-C supports more power on the isolated side without an additional power supply, but as I said, it requires USB 3. USB 3 provides 900 mA, which is enough for Intona, the hub and MOTU M4. A USB 2 cable doesn't give enough power.
E30 is self-powered, so it doesn't have power issues.
 
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Veri

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7055-C supports more power on the isolated side without an additional power supply, but as I said, it requires USB 3. USB 3 provides 900 mA, which is enough for Intona, the hub and MOTU M4. A USB 2 cable doesn't give enough power.
Right. I own an USB 2.0 intona and honestly, it can only power low-energy devices. Even a little audio dongle maxed out in power would make it lose connection at peak consumption :) it works well for devices that hardly need the mA, others not so much.
No experience with the USB 3.0 one.
 

Atanasi

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Right. I own an USB 2.0 intona and honestly, it can only power low-energy devices. Even a little audio dongle maxed out in power would make it lose connection at peak consumption :) it works well for devices that hardly need the mA, others not so much.
No experience with the USB 3.0 one.
I added a USB current meter, and Intona-hub-E30 takes 0.6 A, and Intona-hub-M4 takes 1.2 A. Technically they are both out of spec, except if the first connects with USB 3, but they seemed to work. I think 7055-C has a larger overhead compared to a USB 2 isolator.
 
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