Review and Measurements of Chromecast Audio Digital Output

[TonyB]

I have the CCA gen 2. I just ordered a cable to connect it to an RCA coax input on a DAC. I was told that this would work, but reading this thread I don't think it will without further conversion.

The cable I ordered is a 3.5mm stereo jack to single stereo RCA plug. However, that means I'm inputting an optical signal into coax. I mistakenly though that the CCA output could carry a digital coax signal as well as optical. Could someone please confirm my error and I'll cancel the order and perhaps order an optical to coax converter instead. I don't have a spare optical input, hence the need for coax.

 

[Benedium]

I have the CCA gen 2. I just ordered a cable to connect it to an RCA coax input on a DAC. I was told that this would work, but reading this thread I don't think it will without further conversion.

The cable I ordered is a 3.5mm stereo jack to single stereo RCA plug. However, that means I'm inputting an optical signal into coax. I mistakenly though that the CCA output could carry a digital coax signal as well as optical. Could someone please confirm my error and I'll cancel the order and perhaps order an optical to coax converter instead. I don't have a spare optical input, hence the need for coax.

CCA's 3.5mm stereo jack outputs analog signal also. Not just optical. It's 2 in 1.

 

[TonyB]

CCA's 3.5mm stereo jack outputs analog signal also. Not just optical. It's 2 in 1.

That's true, but in this case I'm looking for a digital signal to feed into a DAC.

 

[BDWoody]

That's true, but in this case I'm looking for a digital signal to feed into a DAC.

You'd need a cable with a mini-toslink connector on the CCA end, and then use some kind of toslink/coax converter if you can't use the optical directly.

 

[Jimbob54]

You'd need a cable with a mini-toslink connector on the CCA end, and then use some kind of toslink/coax converter if you can't use the optical directly.

@TonyB if you have a spare standard toslink cable, one of these will work https://www.amazon.co.uk/CDL-Micro-...ds=mini+toslink+adapter&qid=1615068326&sr=8-3

And for the converter, I have these and work fine https://www.amazon.co.uk/gp/product/B0791YG1X4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[TonyB]

Excellent! I do have a spare toslink cable, so that adaptor will be fine. The converter looks good too. Thanks for the UK links.

 

[Jimbob54]

Excellent! I do have a spare toslink cable, so that adaptor will be fine. The converter looks good too. Thanks for the UK links.

Converter needs power from a micro usb - not sure that is 100% clear from description so at least a spare usb socket on something thats running or a phone charger in a power socket. Makes it a bit of a faff but you could always get a double usb charger if you are socket limited and power both the chromecast and the converter from it.

 

[TonyB]

Thanks, my sockets are always limited so a double USB charger makes sense.

 

[bokolobs]

I have a Cambridge A. AXA35 amplifier paired with speakers ELAC DBR62, a CCA and I'm planning to get a DAC (Topping E30 od Schiit modi 3). The CCA shall be connected to DAC using toslink, and then the DAC shall be connected to the amp, obviously. I'm listening to Tidal and Spotify. So my question is, my dilemma actually, will I improve the sound quality significantly? Does it make sense to purchase a 150$ DAC with this setup?

I had a similar setup (replace your amp with a NAD C 338). What I found was I preferred the sound coming from the E30 to the built-in DAC of the NAD. But even the NAD is superior to the DAC of the CCA. To me, there is an audible difference. But it could be expectation bias–I didn't do a blind test.

 

[GGroch]

......But even the NAD is superior to the DAC of the CCA.....But it could be expectation bias–I didn't do a blind test.

There are measurements of the CCA's internal DAC/Analog out quality at:
- Amir's 44.1K Roon Measurements: .0027 THD+N and 91.3 S/N
- Archimago's 24/96 Plex Measurements which are bit perfect: .0031 and 105.4 S/N
Archemago also provides comparison's to (2015) external DACs and some subjective listening. There is nothing he or Amir measures that suggests any external DAC should objectively sound better.

That said, it appears most CCA users here use an external DAC because as Julf suggests, it makes us feel better and provides a purpose for the CCA's Toslink out. There is nothing wrong with that, I use a CCA with DAC myself. I have a DAC, so, why not.

But, unless there are specific features of your DAC that you want to access (remote volume, source switching etc) I know of no objective justification for it any more than there is objective justification for say, spending the same $150 on an audio cable. But then, spending $150 on cable would not make me feel much better because I do not believe in them, I irrationally have greater belief in the audible impact of DACs.

 

[Willem]

If you are short of inputs of the right kind, an automatic switch with multiple inputs may be a good solution: https://www.tindie.com/products/Beni_Skate/automatic-spdif-opticalrca-audio-switch/ This one was tested by RME and they were very impressed. I bought one, and I can only affirm this. It is also convenient because you never have to worry about selecting the right input.

 

[bokolobs]

There are measurements of the CCA's internal DAC/Analog out quality at:
- Amir's 44.1K Roon Measurements: .0027 THD+N and 91.3 S/N
- Archimago's 24/96 Plex Measurements which are bit perfect: .0031 and 105.4 S/N
Archemago also provides comparison's to (2015) external DACs and some subjective listening. There is nothing he or Amir measures that suggests any external DAC should objectively sound better.

That said, it appears most CCA users here use an external DAC because as Julf suggests, it makes us feel better and provides a purpose for the CCA's Toslink out. There is nothing wrong with that, I use a CCA with DAC myself. I have a DAC, so, why not.

But, unless there are specific features of your DAC that you want to access (remote volume, source switching etc) I know of no objective justification for it any more than there is objective justification for say, spending the same $150 on an audio cable. But then, spending $150 on cable would not make me feel much better because I do not believe in them, I irrationally have greater belief in the audible impact of DACs.

Thanks for the links. I've read these before. I've forgotten how competent the DAC implementation of the CCA is. But I don't quite agree with the comment that "There is nothing he or Amir measures that suggests any external DAC should objectively sound better." Aren't we here in this forum because we want to know the objective measurements to guide us in our purchases and setups? As far as being better, there are DACs featured here that measure better than the CCA. Are you saying that those differences are not audible therefore "should not objectively sound better"? I'm genuinely asking.
That comment piqued my curiosity and spurred me to action. So a few hours ago I set up two CCAs, one, with full dynamic range on, using its analog output to one of my NAD C 338's line in, and another connected to the E30 and that to another line in. I grouped them in Google Home. So I can switch the inputs with close to no delay. I streamed a few tracks using Roon. I don't know how to level match the volumes exactly but I adjust the volume to about the same level while measuring the average SPL to my listening position using my iPhone's mic. I have a pair of Elacs DBR-62. I don't know if my system is resolving the enough, but I could definitely hear a difference! To my ears, the E30 has better separation and the bass is punchier (more controlled?). And the high frequencies are a bit muddy in the Chromecast analog.

I came to this thread again because I wanted to know if it makes sense to use a Schiit Modi 2 Uber I have lying around with the CCA or just use the analog output directly. So I did just that, replacing the E30 from the setup above. I had to adjust the volume when playing through the Schiit by a larger amount to match the volumes. The differences are more subtle this time. But I would still give it to the Modi. By switching between the two inputs quickly, I could tell that the highs are a bit garbled, but only just.

Again, this was not a blind test. I doubt I can tell the difference between the Modi 2 Uber and CCA analog in one. But I think I can do it with the E30 v CCA analog. I'll ask my wife to help me with this later.

But thanks for your comment! That was a fun, well-spent afternoon/evening.

 

[BDWoody]

. So a few hours ago I set up two CCAs, one, with full dynamic range on, using its analog output to one of my NAD C 338's line in, and another connected to the E30 and that to another line in. I grouped them in Google Home

Nice! It is fun to occasionally get inspired enough to do a little personal research.

I have enough around, I should try them compared to other DAC's in a more controlled way. I have mine set up using both analog and digital, but obviously in different systems so comparisons are meaningless.

Did you happen to try this without that full dynamic range setting on? I'm not sure that it's the 'highest fidelity' setting, but I can't remember where I got that impression so could be completely wrong.

 

[nerone]

I had lent the Topping E30 to a friend of mine, in the meantime I used CCA in analogue to the amplifier, the difference is great, I couldn't wait to reconnect it to the E30 via optical.
So CCA definitely sounds better with a good external dac.

 

[Jimbob54]

Nice! It is fun to occasionally get inspired enough to do a little personal research.

I have enough around, I should try them compared to other DAC's in a more controlled way. I have mine set up using both analog and digital, but obviously in different systems so comparisons are meaningless.

Did you happen to try this without that full dynamic range setting on? I'm not sure that it's the 'highest fidelity' setting, but I can't remember where I got that impression so could be completely wrong.

I'd always understood the DR setting to just mean full 2v output, as opposed to the lower so as to not clip crappy little portable speakers.

 

[BDWoody]

I'd always understood the DR setting to just mean full 2v output, as opposed to the lower so as to not clip crappy little portable speakers.

I suppose the question is whether the little CCA is better off with the lower output setting, assuming you have adequate amplification. Might have to see if I can find what I was basing that on...

Edit: Looks like the default, non-HDR setting is actually compressed? Sheesh. Ok, looks like I was way off. May have to try to measure one.

 

[Jimbob54]

I suppose the question is whether the little CCA is better off with the lower output setting, assuming you have adequate amplification. Might have to see if I can find what I was basing that on...

Edit: Looks like the default, non-HDR setting is actually compressed? Sheesh. Ok, looks like I was way off. May have to try to measure one.

Looks like boss man measured analog in a separate thread but I don't think he said how he set up the dynamic range.

 

[bokolobs]

Nice! It is fun to occasionally get inspired enough to do a little personal research.

I have enough around, I should try them compared to other DAC's in a more controlled way. I have mine set up using both analog and digital, but obviously in different systems so comparisons are meaningless.

Did you happen to try this without that full dynamic range setting on? I'm not sure that it's the 'highest fidelity' setting, but I can't remember where I got that impression so could be completely wrong.

I didn't for this test. But I did it a couple of years ago and remember it was louder with full dynamic range on. I still have it set up. I'll test it tomorrow.

 

[Willem]

High dynamic range has nothing to do with dynamic range but with output level. So avoid it unless your preamp can handle a 2V input. 2V into a sensitive preamp will produce clipping on input. Until quite recently I used the analogue output into an old Quad 33 preamp (and Quad electrostats, so a very resolving system). I then replaced the Quad 33 with an RME ADI-2 DAC/preamp for this and other digital sources, and there does seem to be a slight improvement. Whether that is the superior DAC in the RME or the superior quality of the RME unit as a preamp is unclear, but I think the new system just shows off that the late 1960's Quad 33 was an outdated piece of gear. So my conclusion is that maybe, just maybe, a good external DAC is better than the inbuilt DAC of the CCA, but only just, and only in a very good system. Similarly, I tried to compare all the various DACs that I have, and it was very hard to hear any differences between the decent ones. I could not really tell.

 

[Willem]

Hydrogen Audio had some tests with measurements that showed that it was just a level difference, and had nothing to do with compression.