[Questyle]

Hey there @ra990, I checked with the engineers and here's what they had to say:

"The quality and length of the USB cable has a great impact on sound quality, even for digital signals. We recommend to use a shorter USB audio cable with utmost quality. The CMA Fifteen's USB power supply is provided directly from the CMA Fifteen's motherboard, as to better avoid interference from external power sources. And on other note, just for the record, the optical input can support 44.1kHz to 192kHz flexibly, depending on the source material."

The engineers didn't mention anything about the galvanic isolation, perhaps my mistake for not translating that word precisely enough haha

Did that answer your question?

 

[ra990]

Hey there @ra990, I checked with the engineers and here's what they had to say:

"The quality and length of the USB cable has a great impact on sound quality, even for digital signals. We recommend to use a shorter USB audio cable with utmost quality. The CMA Fifteen's USB power supply is provided directly from the CMA Fifteen's motherboard, as to better avoid interference from external power sources. And on other note, just for the record, the optical input can support 44.1kHz to 192kHz flexibly, depending on the source material."

The engineers didn't mention anything about the galvanic isolation, perhaps my mistake for not translating that word precisely enough haha

Did that answer your question?

Thank you so much for getting their input, really appreciate the feedback. I ended up putting a nano iGalvanic3.0 by iFi audio between the PC and CMA 15 and it seems to have done the trick for me.

 

[Questyle]

Thank you so much for getting their input, really appreciate the feedback. I ended up putting a nano iGalvanic3.0 by iFi audio between the PC and CMA 15 and it seems to have done the trick for me.

Ah good to hear this solved the problem. I'll also forward this to the engineers and see what can be learned from this.

 

[WDitters]

Thank you so much for getting their input, really appreciate the feedback. I ended up putting a nano iGalvanic3.0 by iFi audio between the PC and CMA 15 and it seems to have done the trick for me.

USB ports on PCs and cellphones are notoriously noisy.. DAPs and dedicated streamers in comparison provide a much cleaner USB output signal... That's why I prefer source options such as Auralic Aries or Pro-Ject Ultra S2, Volumio, IFI zen Streamer etc

 

[godmax]

Thank you so much for getting their input, really appreciate the feedback. I ended up putting a nano iGalvanic3.0 by iFi audio between the PC and CMA 15 and it seems to have done the trick for me.

Ah good to hear this solved the problem. I'll also forward this to the engineers and see what can be learned from this.

USB ports on PCs and cellphones are notoriously noisy.. DAPs and dedicated streamers in comparison provide a much cleaner USB output signal... That's why I prefer source options such as Auralic Aries or Pro-Ject Ultra S2, Volumio, IFI zen Streamer etc

I use an Intona 7055-c USB 3.0 Isolator to prevent ground loops between my audio gear and the PC. I had issues in the past with this (also the Questyle CMA 400i was affected), but with the isolator I dont have any ground loops anymore since than. Also the iFi Defender 3.0 serves this purpose very well (and is cheaper).

 

[Dynamo5561]

I had PC USB noise issues as well. I could even hear my mouse moving. iFi iDefender+ solved the issue for me. But it needs a separate USB cable from an external power source, otherwise it will not work.

 

[itsnein]

Does someone experience problems with MQA playing?

I am listening using Roon via USB.
Win10.
The latest driver is installed.
Questyle_USBAudio_v4.11.0_2017-06-29_setup

When start scrolling a few songs, and clicking several times to the next song - MQA playing stop working correctly.
There are some delays, and decoding on Questyle can't be initialized.
Also delays in playing, because Roon is trying to establish a decoding connection.
After turn-off/turn-on CMA15 - all good again, until I am starting scrolling again.

the video that shows my experience
https://drive.google.com/file/d/1XuOB_igpzz_4kdt38du0YrxyXGe3nrVc/view

 

[Questyle]

@itsnein Let me forward that problem and the video to the engineers, and see what they have to say. Thank you for the clear description and also the video, that helps a lot! I'll get back to you as soon as I can.

 

[Questyle]

@itsnein

I talked to the engineers, and they are going to check into this further. Can you help provide the following information about the CMA Fifteen in your hands?

• Serial number of the CMA Fifteen
• USB firmware version (see below)

To find the CMA Fifteen's internal USB firmware version, you need to connect it to your PC via USB. Then, find the CMA Fifteen driver on your computer, and within it you'll find a "DFA" tool. The path for this file is: CMA Fifteen USB Driver/For Windows 7, 8, 8.1/QuestyleAudioDfu.exe

Open this DFU tool, and you'll find the internal USB firmware version (see the picture below). If you have any issues with this just let me know and I'll assist.

 

[itsnein]

serial: 1033330021

Thanks for help!

 

[Questyle]

@itsnein

Got it, thank you! Just forwarded this to the engineers, I'll let you know what they say.

 

[Questyle]

@itsnein

Alright, the engineers got back to me and said that you can first try to update the firmware to version v1.18. This update includes changes to the MQA processing and should solve the problem.

I have your email on file so I'll send the newest firmware directly to your gmail account.

 

[ra990]

I was trying the 1/4" output instead of the XLR output and was impressed to not hear any difference. A lot of balanced amps provide the 1/4" out as a convenience and advise to stick to balanced output. What is @Questyle engineers opinion on SE vs BAL out on the CMA Fifteen?

EDIT: After much more listening and comparison with the same cable out of both outputs, I am hearing a narrower stage out of the 1/4" output than the balanced. But, still, 1/4" output is no slouch.

 

[TheMiddleSky]

I was trying the 1/4" output instead of the XLR output and was impressed to not hear any difference. A lot of balanced amps provide the 1/4" out as a convenience and advise to stick to balanced output. What is @Questyle engineers opinion on SE vs BAL out on the CMA Fifteen?

That's interesting opinion. I clearly notice the difference through XLR output (more spacious imaging, better clarity, control and speed) and definitely more power. Tried with multiple headphones as well (dynamic, planar, low/high impedance), the XLR always gave me better result.

 

[ra990]

That's interesting opinion. I clearly notice the difference through XLR output (more spacious imaging, better clarity, control and speed) and definitely more power. Tried with multiple headphones as well (dynamic, planar, low/high impedance), the XLR always gave me better result.

I don't doubt it, there's more power out of the balanced for sure, but I don't hear as much of a difference in sound as I did with amps like the Singxer SA1 or Liquid Platinum.