Where is the DAC on this setup?

coolajami

Novice Member
Joined
Jan 6, 2021
Messages
6
Reaction score
0
Points
26
Age
43
Location
United Kingdom
Hi everyone.
This is may be a trivial question, but I've really cannot find the answer wherever I've looked! so here it goes:

I've have an office setup, where I'm connecting a MacBook Pro to a thunderbolt 3 Dock (Caldigit TS3+), that has an optical audio output, where I connect a set of active speakers with an optical cable.

What I cannot find anywhere, is that where the digital-analogue conversion happens on this setup, in the dock or in the speakers? (I suppose there is an integrated DAC on the Caldigit dock, because it has also an analogue output)

Tried to think this logically and I believe that, as long as the signal through the optical cable is digital, the final conversion will happen in the internal DAC of the speaker and the dock acts only as a "pass-through".

The reason I'm asking is that if I would like to buy an external DAC to connect to the dock, would be make any sense to have an optical output? Or if I'm getting an external DAC, shouldn't the output to be analogue at all cases, so you could get the best out of the DAC?

Sorry if my question sounds very stupid!
 
Last edited:
In the speakers if connected with an optical cable. Optical can only carry digital information.

If you are using an external dac then this should be the last conversion to analogue and be connected to the speakers using an analogue stereo rca cable.

What speakers are you using, it may be that the speakers will be the bottle neck in the system and not able to convey the dac differences.
 
In the speakers if connected with an optical cable. Optical can only carry digital information.

If you are using an external dac then this should be the last conversion to analogue and be connected to the speakers using an analogue stereo rca cable.

What speakers are you using, it may be that the speakers will be the bottle neck in the system and not able to convey the dac differences.
Thanks for the response.
I was thinking the same.

I’m using a pair of Ruark Audio MR1 Mk2 that support optical input. The reason I’m asking is because I’m experiencing sound dropouts when I’m connecting the speakers with the dock with the optical cable. I’ve troubleshooted this vigorously by changing the speakers, the cables, checking ground interferences anything I could. The only thing I could not replace was the Dock itself.
I found that the speakers worked fine with other optical sources (eg TV) and also the dock optical output worked fine when connected with another set of speakers from other brands, but when I’ve tried another pair of the same model of the Ruark speakers, I got the same audio dropouts!

I’ve read in another forum that the old type of integrated speaker DACs can be the source of the problem. The speaker came in the market about 2 years ago, but have no clue what DAC their using and how old is. I’ve got a very cheap DAC that works ok, but I was thinking to invest to a DAC with better quality.
 
Last edited:
Does you MacBook Pro have one of the combi 3.5mm ports that has both analogue and optical output, if so you could try plugging the speakers into this to see if it can work that way.

You could see what it sounds like plugging the headphone output on the doc or MacBook into the aux on the speakers. That way you can compare the dac in the doc, MacBook and speakers to see if you hear a difference.

If you go does the dac route the Smsl Sanskrit 10th mk2 is getting good reviews for £100, connect to the USB ports and off you go, you will need a 3.5mm to rca stereo cable to connect to the speaker aux input. This has volume control as well so you can play around with the speaker, dac and MacBook (app and system) volume to see what sound the best. The dragon fire Red is another to look at but this is getting a little old now.
 
Have you hired the analogue input from the dock to the Ruarks?

If you have and there are no drop outs then at least you know for certain it’s the optical route with the issue.
 
Does you MacBook Pro have one of the combi 3.5mm ports that has both analogue and optical output, if so you could try plugging the speakers into this to see if it can work that way.

You could see what it sounds like plugging the headphone output on the doc or MacBook into the aux on the speakers. That way you can compare the dac in the doc, MacBook and speakers to see if you hear a difference.

Have you hired the analogue input from the dock to the Ruarks?

If you have and there are no drop outs then at least you know for certain it’s the optical route with the issue.

My MacBook Pro is a 2018 one, so no optical for me unfortunately. The speakers work fine with the analogue outputs of both the MacBook Pro and the dock, and I'm currently using the analogue output of the dock.

I've tried another pair of the exact same model with the dock, and I was still getting the same dropouts, so naturally I thought that the problem was with the dock.
What made my jaw dropped was when I've tried another pair from another brand with optical input, and the sound was fine when connected with the dock!

I lean to believe that there is an inherit miss-match between the dock optical output and the speakers DAC.Is this possible to be some incompatibility with the supported data-sets? Both Caldigit and Ruark provide no info whatsoever about the bitrate they support so this just leave me in limbo. It is not like I'm desperate to get the optical working, but it's really bugging me that I cannot find what's going on.

If you go does the dac route the Smsl Sanskrit 10th mk2 is getting good reviews for £100, connect to the USB ports and off you go, you will need a 3.5mm to rca stereo cable to connect to the speaker aux input. This has volume control as well so you can play around with the speaker, dac and MacBook (app and system) volume to see what sound the best. The dragon fire Red is another to look at but this is getting a little old now.

I got a Fiio K3 DAC as an emergency purchase, and works well; it has an optical output. Quality-wise I haven't really notice particular difference in the sound when I've tested the optical and the analogue output of the DAC with different sets of speakers.
I'm thinking now to upgrade to an Audiolab m-DAC mini that also has an optical output and it made me wonder, what is the purpose of its existence? I was thinking exactly the same, the output of an external DAC should be in analogue format.
 
Last edited:
Is it possible your dock setting has something setup that the Ruarks can't deal with,wrong bit rate or something
 
If you are using optical out from the laptop or the dock into the dac and then optical out from the dac then the dac is doing nothing other than maybe reading the data and passing it to the output. Digital data in, digital data out, that is unless the output is limited to less nitrate than the input say 24/96 in and 16/44 out.
 
Thanks for the last responses.
I wanted to confirm this, because I found peculiar that a DAC offers digital output in that price range.

Yes, it does sound there is a miss-match in the bitrate between the dock and the speakers, most likely the dock output higher bitrate than the speakers can handle. I'll see if I can manipulate the output bitrate with a third party software (highly unlikely) and see if that makes the trick.

I'll be asking the manufacturers as well for this information but it is likely to claim that this is proprietary information possible in order to avoid admitting that they put crappy DACs on their units.
 
Not sure about IOS but in windows in the sound setup you can set the output bitrate, maybe worth setting this to 16/44 if you can and see if this calms things down, I would expect this to be the minimum that the speakers will be speced at.

I am not sure why you need to use the optical input on the speakers if you have an external dac. Plug the Dac into a USB port on either the doc or the macbook and then plug the analogue output from the dac into the aux input on the speakers. This will cut out any issue with either the doc or the speakers in terms of digital compatibility.
 
I’d agree that the first thing to check is the differing bit rate outputs from the Mac. Assuming the dock does not then upsample them before sending the signal to the speakers.
 
Not sure about IOS but in windows in the sound setup you can set the output bitrate, maybe worth setting this to 16/44 if you can and see if this calms things down, I would expect this to be the minimum that the speakers will be speced at.

I am not sure why you need to use the optical input on the speakers if you have an external dac. Plug the Dac into a USB port on either the doc or the macbook and then plug the analogue output from the dac into the aux input on the speakers. This will cut out any issue with either the doc or the speakers in terms of digital compatibility.

I’d agree that the first thing to check is the differing bit rate outputs from the Mac. Assuming the dock does not then upsample them before sending the signal to the speakers.

I have a virtual audio interface in MacOS and I'll play around to see if there is any improvement in the audio through optical.

I'm not particularly worry about the performance of the optical output as I'm using the DAC for the analogue conversion now, but it has been bugging me and want to find what's going on. The speakers cost $400 and the dock another $300 and I think it is reasonably to expect that they should have provide some more more info on this.

As far as I know, some devices with onboard sound chips will resample the audio stream before exporting it, so the digital stream that the DAC/Speakers will handle it’s not the same as the original stream that is generated from the decoding of the source file.

Normally the dock should have act as a "pass-through" only, but it is unclear from the specifications if its onboard sound chip does any processing or resampling of the audio stream that comes from the Macbook Pro, before exporting it in the optical output. In that case whatever tweaks I do in the virtual audio interface may not affect the digital output of the dock. Bummer.
 
Last edited:
Late to the thread, but I just plugged my AKG K702's into my CalDigit TS3 and the audio is incredible! It must have a DAC chip, and a good one...
 

The latest video from AVForums

Is 4K Blu-ray Worth It?
Subscribe to our YouTube channel
Back
Top Bottom