[megamlody]

Hey guys!
Just bought a CMA600i recently. I was wondering about that hardware "upgrade" to fix the popping issues. I had a look inside and around the DAC section on the PCB there was this handmade soldering job (see attachment). Is that the "upgrade"?



My serial # is above 500 and firmware is 6.f3. Just curious as i bought the cma600i mainly for its superb headphone amp. I'm looking forward to exploiting that analog input
Also maybe the image will be useful to others who have had the upgrade or want to see how it (should?) looks like. Cheers!

 

[streamline]

From the linked article:

"Upon further digging, it turns out that this RCA input is actually converted to digital signal by an A/D chip and then back to analog again as it joins the rest of the signal path outward."

Well that is disappointing. The headamp section of the AIO is essentially unusable -- I kinda want a full analog amp stage if I'm going pair it with an upgraded DAC. It looks like Questyle deliberately crippled the amp.

Could someone confirm?

https://audio-head.com/questyle-cma-600i-review/

 

[esauseesaw]

From the linked article:

"Upon further digging, it turns out that this RCA input is actually converted to digital signal by an A/D chip and then back to analog again as it joins the rest of the signal path outward."

Well that is disappointing. The headamp section of the AIO is essentially unusable -- I kinda want a full analog amp stage if I'm going pair it with an upgraded DAC. It looks like Questyle deliberately crippled the amp.

Could someone confirm?

https://audio-head.com/questyle-cma-600i-review/

That is a surprise to me. I've never seen this mentioned before. Using A-D would open up questions about sq based on the chip used and implementation.

I've put one on the bench here to take a look and the external input would appear to be on the analogue section of the board. The digital section, which sits in front of digital inputs is outlined separately, with the DAC chip coming last. The anlogue input would have to enter the digital section at some point, which I can't see and also can't see an obvious A-D chip. Unfortunately our main engineer is on holiday today so I can't get his more knowledgeable input.

I'll ask Questyle to confirm. Without the circuit diagram, which we don't have, it's harder to give a conclusive answer straight away.

 

[Blueshound24]

Does anyone know what the output impedance is with the 600i on the SE and balanced outputs? Just curious how others experience has been with sensitive IEM's, and if it would benefit from using something like the iFi Audio iEMatch.

 

[ProLoL]

Using R2R 11 as dac feeding the CMA600i, dat musicality! wow so fun.

 

[Blueshound24]

Using R2R 11 as dac feeding the CMA600i, dat musicality! wow so fun.

Agreed. It is a wonderful sounding amp fed by my PS Audio DAC as well. Looking forward to upgrading to a ladder DAC in the future.

 

[streamline]

Agreed. It is a wonderful sounding amp fed by my PS Audio DAC as well. Looking forward to upgrading to a ladder DAC in the future.

The interesting thing is that until Questyle can confirm differently, there is no way to take the built-in DAC out of the CMA600i's signal path; see my post above and link to the article. The A/D to D/A conversion might very well be transparent enough to allow improvements with upgraded DACs, so I'm not questioning what people are hearing.

 

[up late]

Does anyone know what the output impedance is with the 600i on the SE and balanced outputs? Just curious how others experience has been with sensitive IEM's, and if it would benefit from using something like the iFi Audio iEMatch.

i asked the same question after not being able to find it in questyle's specs or anywhere else on the interwebs

 

[John Aiello]

Agreed. It is a wonderful sounding amp fed by my PS Audio DAC as well. Looking forward to upgrading to a ladder DAC in the future.

How are you feeding the CMA600i from the PS Audio DAC? It must be analog as there are no digital outputs to feed it that way?

 

[ProLoL]

Anyone knows why my unit shows blue light on pcm while playing DSD?

 

[Blueshound24]

How are you feeding the CMA600i from the PS Audio DAC? It must be analog as there are no digital outputs to feed it that way?

Yes, just the RCA inputs for now. Haven't tried, but plan to try the balanced inputs. I am concerned of splitting the DAC's output too many ways to my different amps.

 

[Blueshound24]

The interesting thing is that until Questyle can confirm differently, there is no way to take the built-in DAC out of the CMA600i's signal path; see my post above and link to the article. The A/D to D/A conversion might very well be transparent enough to allow improvements with upgraded DACs, so I'm not questioning what people are hearing.

Haven't had a chance to read the article you posted. Are you saying that from my DAC to the RCA input of the 600i it then converts it to digital, then back to analog? If so, I would find that highly unorthodox.

Edit:
And what would be the supposed benefit of adding another middleman into the equation?

 

[streamline]

Haven't had a chance to read the article you posted. Are you saying that from my DAC to the RCA input of the 600i it then converts it to digital, then back to analog? If so, I would find that highly unorthodox.

Edit:
And what would be the supposed benefit of adding another middleman into the equation?

Yes, that is what I'm saying. There isn't any confirmation from Questyle (still awaiting that), but the article says there is A/D conversion done on the analog (RCA) inputs of the CMA600i. I won't speculate on any benefit, but I will agree it's not common -- I do remember some high-priced DACs/pre-amps all-in-ones from late 90's early 00's taking this approach though. (Wadia? Theta? EAD? It was long ago so don't take my memory for this lol.)

If true, what it does do for sure, is discourage people from buying the CMA600i just for relatively low-cost access to Questyle's current mode amplification technology, or for use as as bare-bones preamp. It makes the CMA600i purely a DAC that can also drive headphones, which not incidentally, is how it's marketed.

 

[stevedlu]

FINALLY got my Chord Qutest in after much delay. I let it ""burn in" and let my ears get used to it over a couple of weeks. I have to say the CMA600i/Qutest combo is simply stunning with my LCD-3s. Better detail retrieval, wider soundstage/separation than my previous CMA600I/Mojo combo, same great tone and dynamics though.

 

[Blueshound24]

Yes, that is what I'm saying. There isn't any confirmation from Questyle (still awaiting that), but the article says there is A/D conversion done on the analog (RCA) inputs of the CMA600i. I won't speculate on any benefit, but I will agree it's not common -- I do remember some high-priced DACs/pre-amps all-in-ones from late 90's early 00's taking this approach though. (Wadia? Theta? EAD? It was long ago so don't take my memory for this lol.)

If true, what it does do for sure, is discourage people from buying the CMA600i just for relatively low-cost access to Questyle's current mode amplification technology, or for use as as bare-bones preamp. It makes the CMA600i purely a DAC that can also drive headphones, which not incidentally, is how it's marketed.

"there is A/D conversion done on the analog (RCA) inputs of the CMA600i"

So is this supposedly done on balanced input as well?