New DAC has distorted/clipped audio w/new Mac and OS 10.10

[John Swenson]

I tried to downgrade my 2014 mac mini to Mavericks, but I can't.  It was shipped with 10.10 Yosemite and you can't downgrade to anything earlier than what a mac was shipped with.  I didn't know that.  All the info you need to know is here: https://support.apple.com/en-us/HT204319

When I did have USB working on an older mac, USB audio was subtley better than toslink.  I prefer USB.

So until this gets resolved, I'm choosing between toslink or using an older laptop for my music source.

I really want to get to the bottom of this. As I mentioned earlier it's tough to try and work through this without knowing what the distortion is. Is there any way at all you can make a recording of the distortion so I can analyze it and try and see what is happening? At this point I'll take anything, use a voice recorder function on your phone to record it, the mic input of a laptop, anything you have on hand. If you have a choice record at a high sample rate if possible.

Thanks,

John S.

Once I have a clue as to what the distortion is I can start trying to figure out what is causing that distortion.

 

[John Swenson]

I have experienced this sound in the last week a couple of times.  It is always when I start a new CD.  I found that switching inputs and back solves this problem.  So I'm just careful at the start of a disk.  Since I'm at the DAC to put in a new disk it is pretty minor.

It is the DAC as the analog outputs are fine.  But it might be some anomaly with my CD player at the start of a disk.

Hi Grainger,
could you give me some details of the sequence of events that causes the problems for you? What input are you using? What sequence of powering on or off the CD player and DAC is happening? Have you been listening to another input?

Really helpful would be things like: I do A then B it works fine, but when I do A C then B it doesn't.

Thanks,

John S.

 

[Grainger49]

Yes John, It happens after listening for a while and when I close the tray (Philips DVD 963SA using SPDIF output) it sounds very odd.  I'll see if I can just open/close the same CD until I get the noise.  I have a recorder on my phone, but it is very low quality.

I have also ordered a TOSlink long enough to go to an OPPO CD/DVD player.  Once that arrives I will see if it happens there.

 

[aroide]

John,

I switched to using an older laptop (Ivybridge based) to work around the issue.  The DAC really shines through USB vs toslink and I didn't want to compromise.  When I get a chance, I'll hook my 2014 mac min back up and record the sound.

The distorted sound only happens for my using Audirvana.  I get that sound for a few seconds and the DAC no longer is recognized.  Audirvana uses integer mode of USB audio 2.0 and may be unique.  If I try and drive the DAC from the OS X system sound, I get NO SOUND at all and within 2 secs the BH DAC disappears as a device.  So the distortion may or may not give you a clue.

What I really want to do is to bring my DAC to work and get some traces on a USB gen 2 protocol analyzer.  If I can get some traces, are those useful to you?  I know for my team, its hard to use a trace without firmware source and driver source.

Tony

 

[Grainger49]

It hasn't happened to me again.  I got the TOSlink and haven't gotten it fished behind my cabinets yet.  There is not much room to work with.  It will not reach around the front it isn't long enough.

It might not have happened again since I haven't listened more than a couple of hours since it happened.  I'll try turning the system on, putting the CD on repeat and give it 4 hours to see.  It very well might be the Philips.

 

[Bodyslam]

Grainger,
Since you're using a DVD player, which is primarily designed as a video player, it very likely switches back to the 48K family of sample rates whenever it doesn't have a recognized CD in it. Can you look at the sample rate display on the BottleDAC when you open the tray and see what it's reporting?

The Oppo will probably do the same thing.

 

[Grainger49]

Two answers.  Paul, I just ran a test today.  I went up and opened and closed the player 6 times.  The displayed sample rate stayed at 44.1.

John, the above test was after the system played for 5 hours.  So it doesn't seem to have anything to do with the player being "hinky" after hours of listening. 

 

[John Swenson]

John,

I switched to using an older laptop (Ivybridge based) to work around the issue.  The DAC really shines through USB vs toslink and I didn't want to compromise.  When I get a chance, I'll hook my 2014 mac min back up and record the sound.

The distorted sound only happens for my using Audirvana.  I get that sound for a few seconds and the DAC no longer is recognized.  Audirvana uses integer mode of USB audio 2.0 and may be unique.  If I try and drive the DAC from the OS X system sound, I get NO SOUND at all and within 2 secs the BH DAC disappears as a device.  So the distortion may or may not give you a clue.

What I really want to do is to bring my DAC to work and get some traces on a USB gen 2 protocol analyzer.  If I can get some traces, are those useful to you?  I know for my team, its hard to use a trace without firmware source and driver source.

Tony

Hi Tony,
so it works fine with another computer? It's just this one Mac Mini that has the problem?

Yes a protocol trace on the machine that has the problem would be a big help in tracking this down.

The BH DAC has been run in integer mode with Audirvana many times without any problem, so I don't think that per se is the issue. It might be some interaction between that and other setting you have that don't exist on other's Mac Minis.

Thanks for sticking with this, I really want to get it figured out.

John S.

 

[fullheadofnothing]

John-

This problem has been traced to ONLY be an issue when running a Mac with 10.10 AND USB 3.0. USB 3.0 works on OS 10.9. OS 10.10 works on USB 2.0. This is an issue with Apple's software. This is why I have been suggesting that those experiencing the issue contact Apple. The DAC that Tony has was tested here on multiple computers before it was ever sent to him. After he encountered issues, he sent it back to us, where we verified it further.

Grainger's issues are completely different from what Tony has been talking about. I believe it is the issue that I encountered and wrote to you about previously (with recordings, that you identified as "[...]is caused by the S/PDIF receiver (either optical or coax) having a signal, but the clock tracking circuit is prevented from tracking because USB uses a fixed frequency clock, when switched to S/PDIF (coax or optical) the buffer is now so far out of whack with the data that it is messed for a while until the tracking mechanism can get synched up.")

 

[Grainger49]

John and Josh,

I don't consider it to be much of a problem.  If it bothers you guys we can continue with it.  But I'm very happy.

 

[aroide]

I'll see when I can find the time to try and get a protocol analyzer hooked up.  I'm no expert at these details so I need help from my team (I'm the lowly manager type).

I wouldn't jump to a conclusion that this is exclusively an apple issue.  My other xmos dacs work just fine where the bh dac does not.  My team at work encounters these interactions all the time and normally it is some subtle disconnect in implementations or different interpretations of a protocol or spec.

I fear that apple changed USB hub chips and there has been a hardware change that is part of the issue.  It happens on all 2014 and 2015 macs starting with the Haswell processor versions.

For now I'm back to a mid-2012 MacBook Air to work around the issue and the bh dac works fine.  Btw this is USB 3 system running OS X 10.10.3 using the intel hub.  On my 2014 Mac mini the sub ports connect through a Broadcom hub chip.

 

[Doc B]

Thanks Tony, it would be great if you could share any info you may find. Knowing how well the DAC works with every setup but this one combination will hopefully motivate us to work together toward a solution.

 

[caffeinator]

I just saw this thread and started writing in response before I realized it is a few months old.

FWIW, what aroide was describing sounds very similar to what I heard when I upgraded my Mac Mini to OS 10.10.5 - a painfully harsh chopped kind of sound, like the music was literally going through some kind of chopper (intermittently cutting out time-slices).  Recognizable as music, yes, but beyond unlistenable.

In my case, after restarting, then being sure Amarra was running, the problem seems to have gone away, though the sample rate display seems to read 44.1 all the time, even when playing higher-res files - I am still trying to test that more thoroughly, though.