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Seriously I'm not trolling these are real questions!

S

saitong

New Member
Somewhat confused…so the question (s) about an external DAC for a CD player/transport; as I've continued to research the possibility of getting an external DAC and trying to understand them:

When using a Digital optical/coaxial connection, you're just sending bits to your Receiver's DAC, so it's just your Receiver's DAC that is processing the info…the external DAC's I've seen (advertised) have optical/coaxial input & output, few have analog; so based on this, (not counting say the power supply of the dac; the biggest aspect to supposedly better DAC's is the same issue with nearly every electronic device, its power supply.) the cd player, or transport digital outputs to the dac, the dac digital outputs to your receiver; what's the purpose of an external DAC then; transport then yes, but upgrading a DAC for a CD player?

If you originally have a just a pretty good CD player, not a SACD playing SACD CDs, then it's Redbook, so to my understanding the highest depth is 16 bits with a 44.1 khz sampling rate (1,411 kbps) then what are you going to get with an external DAC unless you cross, say, the $3 grand threshold and above; under this $ can you really hear, not just perceived, the advanced DAC circuitry?

My only other question is I've read some say coaxial is better than optical, (I'm only guessing because of twists and turns, I really don't know), but coaxial only outputs 2 channels, so you end up with only stereo, but I guess that's just fine for music.
 
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So given that a DAC is a Digital to Analog Converter, you feed it a digital signal from a digital source (CD player via optical or coaxial cable, computer via USB cable), then you let the DAC convert the digital signal and use the DACs analog output to your receiver.

Frankly, it doesn't make sense to put a DAC in a signal path if it doesn't decode it from digital to analog.

Here's a silly path: Source ===> digital ===> DAC ===> digital ===> Receiver digital input. In this case the external DAC is doing nothing with the digital file and everything is being decoded by the receiver's DAC.

Now here's a better path that takes advantage of the external DACs chipsets to decode the digital file:

Source ===> digital ===> DAC ===> analog ===> Receiver analog L/R input

Don't rely on the DAC to upsample the digital signal. Yes, standard redbook CD is produced at 16/44.1 but some may produce 24/96 in rare cases. I use my DAC to decode 16/44.1, 24/96 & 24/192 FLAC files that were either ripped from CDs or downloaded from internet high resolution music sellers. My point here is that a DAC usually just decodes the file and sends it along to the rest of the system with little to no fiddling to upgrade the file. Good source files sound good, not so good source files sound not so good.

You don't have to spend big bucks on a DAC to convert your digital music to analog. For instance, a good little DAC, the Schiit Modi starts at $99 and can be upgraded. Of course there are DACs that cost big bucks. The value test is how good, or bad, they sound to you decoding the same source file.

I think in addition to the power supply, the chipsets are an important aspect to the DAC. I have heard a LOT of DACs in my system and, to my ears, the DACs with the ESS chipsets sounded best. Like many other components some sound different from others and a DAC is no exception.
 
I would suggest that the opamp section of th DAC plays as great or greater role than the chipset. As with all things audio, there are many variables that impact the performance of a given DAC, be it internal or external. In addition to opamp and chipset variation, some others are power supply, electrical isolation, mechanical isolation, component quality, etc.

I definitely agree, based on my own experiences, that various DACs have varying sonic characteristics. I would also say that such variance can be found bothabove and below the arbitrary $3K threshold you established.

Re: your question about coax vs optical. Both are only for audio. Multi channel audio requires optical input to DAC. Coax offers higher bandwidth capability, so can handle 24/192 bitstream. Optical, I believe, is limited to 24/96.
 
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Most vintage receivers were invented before CDs - they expect analog input (like vinyl). CD players output analog so they must have an internal DAC. Some CD players output digital as well as analog.
So why get external DAC if CD player already has DAC? I assume this is your question.

If your CD player can output digital (usually optical or coax) then it is bypassing the internal DAC and you can compare the sound to external DAC.

The reason then is one DAC sounds better than the other. (maybe)

For me I do not expect magic. You can get an external DAC for whatever. I think the best use of external DAC is to connect a computer to play music.
 
rwartner said:
Most vintage receivers were invented before CDs - they expect analog input (like vinyl). CD players output analog so they must have an internal DAC. Some CD players output digital as well as analog.
So why get external DAC if CD player already has DAC? I assume this is your question.

If your CD player can output digital (usually optical or coax) then it is bypassing the internal DAC and you can compare the sound to external DAC.

The reason then is one DAC sounds better than the other. (maybe)

For me I do not expect magic. You can get an external DAC for whatever. I think the best use of external DAC is to connect a computer to play music.
Click to expand...
Thank You
 
Yamaki said:
Here's a silly path: Source ===> digital ===> DAC ===> digital ===> Receiver digital input. In this case the external DAC is doing nothing with the digital file and everything is being decoded by the receiver's DAC.

Now here's a better path that takes advantage of the external DACs chipsets to decode the digital file:

Source ===> digital ===> DAC ===> analog ===> Receiver analog L/R input
.
Click to expand...

You can’t use a DAC in the first example you provide - an upsampler or reclocker yes, but not a DAC.

The latter example makes sense and is technically correct.
 
pete_mac said:
You can’t use a DAC in the first example you provide - an upsampler or reclocker yes, but not a DAC.

The latter example makes sense and is technically correct.
Click to expand...

Yup...that's why I called it a "silly path". ;)
 
JoeESP9 said:
Actually, quite a few do deliver a digital output. My Topping D-10 has a USB input, a pair of analog (RCA) output jacks and both optical and coax SPDIF outputs.
Click to expand...
So, the equipment bypasses the DAC and instead convert's usb to S/PDIF? Or does it convert to analog and then use a ADC to produce digital output.
 
SterlingOne said:
How is it possible to deliver digital output from a DAC?
Click to expand...

Some DACs (as a descriptor for a metal box which contains various circuits) do have digital output capabilities - this is typically achieved via the digital receiver chip which converts, say, a USB input to a coaxial or optical digital output and which sits upstream of the DAC chip.

The DAC chip itself is not involved in this process.

You will also find this kind of circuit inside the USB to SPDIF converters out there in the market, generally with some form of signal reclocking.
 
pete_mac said:
Some DACs (as a descriptor for a metal box which contains various circuits) do have digital output capabilities - this is typically achieved via the digital receiver chip which converts, say, a USB input to a coaxial or optical digital output and which sits upstream of the DAC chip.

The DAC chip itself is not involved in this process.

You will also find this kind of circuit inside the USB to SPDIF converters out there in the market, generally with some form of signal reclocking.
Click to expand...
Yeah, my Creative Sound Blaster X-FI HD converts usb to S/PDIF up to 24/96.
 
pete_mac said:
The DAC chip itself is not involved in this process.
Click to expand...

Sometimes it is... I'm currently using a cheap (£5 delivered) TI PCM2704C USB DAC to play with SPDIF recording on a Philips CDR796. The 2704 provides the USB interface, an SPDIF output (digital decode from the USB data stream), and a headphone output.The little board I have provides coax and optical SPDIF outputs.
 
JoeESP9 said:
USB DAC's that have coax and/or optical outputs do a direct conversion. They do not convert to analog first.
Click to expand...

Yes, S/PDIF coax/optical "Pass through", when the DAC is not being fed a USB input(if available), in which it is then digital signal type converting(transcoding ?).. :thumbsup:
 
With my Topping D-10, if there is no signal on the USB input (only input) there is no signal on the optical or coax output. They are outputs only.
 
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