[brj]

Currently my music is all streamed from my Macbook Pro to my main rig via a modded SB Touch and all is well.

As I have yet to find a solution to stream the audio channels of a video source from the Mac to the SB Touch without lag, however, I picked up a 3.5mm mini-plug to RCA S/PDIF cable.  I simply unplug the S/PDIF connection from my SB Touch to the DAC and plug in my MBP.

(There are various software packages, such as like Nicecast, that let you capture and stream all audio signals from your Mac to the source of your choice.  Unfortunately, every one I've tried introduces some lag, which is a problem if that audio is supposed to be synced up to video, ala that cool wakeboarding video you recorded with your HD Hero digital video camera! )

The problem is that my MPB doesn't seem to recognize the connection to the DAC as a digital connection.  The (headphone) jack can output either analog or digital audio, but I don't know specifically how it determines which type of signal to send, and I think I might be caught in a catch-22.  My DAC doesn't come out of stand-by until it senses a S/PDIF signal, and I suspect the Mac assumes an analog connection unless it establishes some type of digital hand-shake with whatever is on the other end of the cable.  Since the DAC is autosensing, there is no hand-shake to establish and the Mac stays in analog mode.

This is just theory on my part, but it at least sounds reasonable.  The cable could also be bad, but I don't have another DAC which which to test that, so for now, I'm assuming that isn't the problem.

So the questions is... is there a setting somewhere that will let me force the Mac into treating the headphone jack as a digital output?

Many thanks for any suggestions!

[jrebman]

Brian,

You have to go into audiomidi settings in the utilities folder of the applications folder on the main drive.  Or as somebody just pointed out the other day, hold the option key when clicking on the volume icon on the menu bar.  Then just select the digital out for the built-in output (optical/spdif).

HTH,

Jim

[brj]

Thanks, Jim.  Yep, I've been down that path... no luck.

However, I think I just figured it out.  While nothing in the Macbook specs indicates that the "digital" output is optical, the similar mini-jack connection on the desktop Macs are labelled as optical digital outputs.  As an example, you can find it in the iMac specs.

Following that discovery, I then found a youtube video of a guy connecting a mini-jack to Toslink cable from his Macbook to his receiver.

Unfortunately, my DAC only handles S/PDIF over coax, as it has no Toslink connector.  So now I have a needless cable and still no way to play synced audio/video from my MPB over my stereo.  Grrr.  That really seems like a rather crucial omission from the MBP specs page!

Thanks anyway!

[timind]

You can always get a Monarchy Audio DIP, or a similar product to convert the optical signal to coax. It made a significant difference in my system.

[jrebman]

Hey Brian,

Ah, well maybe Apple just assumes that people know the spdif connection out of Macs is optical -- every Mac I've ever seen only has optical spdif outs -- unless there are some older models or maybe the mac pro that uses a coax connection, but those are well before my time with Macs.

Of course I was expecting there to be an optical connection on my MBA, but it is nowhere to be found, so for whatever reason, perhaps saving power consumption, they left the optical out off the 11" MBA.

I think your best bet is something like Timmond mentioned, or use something like a Halide bridge and a usb connection.  Also, the AMB gamma1 micro dac can be built in a configuration where it can be used as an optical to coax converter, but I'm not sure if the one I have can do that or not.

Sorry for assuming you knew that the spdif connection was optical only.

-- Jim

[skunark]

Brian,

You need a mini-toslink to toslink cable not the coaxial one.   The mini-jack will auto-dected the if it's a headphone(analog) or mini-toslink(digital).   

Jim,

I remember reading about the newer macbook airs switching to the headset mini-jack just like the iPhones, but it is interesting to know they they dropped the optical from the mini-jack.

Jim

[brj]

Thanks, guys.

Yeah, my Mac experience jumped from a Mac LC circa 1991 to my 2011 MBP.  (Yikes... I'd never appreciated the full 20 year gap until I wrote that!)  The interim has been mostly filled with UNIX/Linux boxen for real work and PCs for email and office applications at work.

Honestly, my interest in the digital out was rather an impromptu affair spurred by my desire to watch a few videos with better sound than what the built-in speakers provide. I'd never had need to examine it previously and didn't key to the optical nature of the output until I found specs for the similar output jack on the desktop Macs that better described it.

That said, my interest in turning this into a permanent solution is sufficiently limited that I can't justify something as expensive as the Monarchy Audio DIP for this purpose.  (For that price, I'd probably start looking at inexpensive USB DACs.)  It appears that there are several inexpensive converters, but it might be even easier to just add an optical receiver to my DAC, ala the Twisted Pear TOSLINK Optical Input Module Kit.  (Though not if doing so will compromise the quality of the coax input that I feed from my BOLDER Squeezebox Touch.)

Thanks again!