How do I get a digital signal out of my 2015 iMac to interface with a headphone amp/DAC?

You need a Digital Toshlink cable with a 3.5mm plug on one end to plug into the 2015 iMac.

for examples:

https://www.skaastore.com/products/toslink-to-3-5-mm-cable

https://www.amazon.com/Diarypiece-Toslink-Digital-Optical-Connector/dp/B0BVG1XY8Y/ref=asc_df_B0BVG1XY8Y?

Or a 3.5mm Digital adapter to put on an existing Digital Toshlink cable.

for example:

https://www.amazon.com/Digital-Fiber-Toslink-Adaptor-Optical/dp/B074Z416CG/ref=pd_ci_mcx_di_int_sccai_cn_d_sccl_2_1/130-9681124-3129360?

Side note:

The 2015 iMac was the last year model that supported Digital output from the headphone port.

Hey! No stress — let’s clear this up for you.

Your 2015 iMac actually has a pretty neat trick: the headphone jack is also a mini-TOSLINK optical digital out. So yup — it can send out a digital signal!

Here’s what you need to do:

1. Grab a mini-TOSLINK to TOSLINK optical cable (not too expensive online).
2. Plug the mini end into your iMac’s headphone jack.
3. Plug the TOSLINK end into your DAC’s optical input.
4. Head to System Settings > Sound > Output and select Digital Out or your DAC (if recognized).

That’ll send pure digital audio straight from your iMac to your headphone amp/DAC — no USB driver drama, just clean sound.

Let me know what DAC you’re using if you want help checking compatibility or setting sample rate stuff. You got this!

Exactly which make and model DAC do you want to interface with?

The 2015 iMac does digital audio via optical output at its headphone jack. You can find 3.5mm mini optical cable if you search Amazon or google it. Cables and adapters for mini optical and TOSLINK are available.

Another option for getting digital audio out of a Mac is some flavor of USB audio converter. Again, if you search Amazon or google it, there are many to choose among.

Some do USB to 3.5mm analog headphone output. Some are USB to SP/DIF optical output. Mono Stereo. Whatever you need.

If you explain exactly what your end game is, users here can offer more specific guidance.

You're welcome.

Your questions are ❝How is the quality of the audio using the 3.5mm/optical plug? Is it still going thru the pre amp in the iMac?❞

I don't know the specs of the iMac's digital signal, it is what it is. The quality of the digital signal is typical of the type and much better than any analog signal. The digital output of the iMac's headphone jack is switched on by inserting an optical cable plug - different than analog stereo plug - and bypasses any analog preamp.

The proper optical plug for the iMac's jack is a 3.5mm mini optical plug. The plug for the FiiO DAC input is standard TOSLink. To connect the iMac's output to the FiiO DAC input, I expect this TOSLink cable and adapter would work:

AudioQuest Forest Optical TOSlink Fiber-optic Cable and Mini Adapter - Sweetwater

Of course there are others, and as long as you buy the correct plug for each device you should be okay. After all, an optical signal is an optical signal.

TomRZO6 wrote:

My 2015 iMac has USB type 3.0 ports I believe and I need to do a firmware update on my FiiO K7 amp/dac which has a USB type B connector. what kind of cable should I purchase ?

If you intend to have a digital audio connection from your iMac to your FiiO K7 you would use a Toslink-to-3.5mm (aka mini-Toslink) optical cable like this one.

To do a firmware update to your FiiO K7 you would use a USB-A to USB-B cable like this one (commonly called a USB printer cable).

You have 2 options to connect the FiiO K7 DAC/Amp to your 2015 iMac.

1) use a Digital Toslink cable with a 3.5mm adapter and plug that into the iMac's headphone port.

2) use the supplied USB cable that comes with the FiiO K7 DAC/Amp plugged into the iMac USB port.

TomRZO6 wrote:

And that will work even though the iMac has USB 3.0 ??

Yes. Your iMac and FiiO both support USB. It doesn't matter that your iMac is USB 3.0. The USB-B connector on your FiiO device is an indication that it supports USB 2.0 or USB 3.0. The FiiO specs don't say which. But in either case it will work fine with your iMac, they are USB-compatible.

One other thing, you can use either an optical connection or a USB connection for digital audio. In my earlier post I was trying to make it clear that in order to do a firmware update you *must* use USB.