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Newbie DAC question

post #1 of 22
Thread Starter 
Thinking about getting a DAC. My question is when hooking up a Blu-ray player, i need to hook it into the DAC( via optical or Coax) then the Blu-ray back to my AVR(via HDMI)? If this is correct, how does the AVR know to bypass the audio from the HDMI? Is the something i need to set on my AVR(Marantz SR7005) Thanks.
post #2 of 22
Quote:
Thinking about getting a DAC.
Why? That's a serious question. A DAC would seem to be pointless in your case.
Quote:
My question is when hooking up a Blu-ray player, i need to hook it into the DAC( via optical or Coax) then the Blu-ray back to my AVR(via HDMI)? If this is correct, how does the AVR know to bypass the audio from the HDMI?
The HDMI from the BRP and the analog cable from the DAC would be two separate inputs, even though they start from the same source component. So you'd just switch from one to the other, as you would any two sources.

But again, the question is, why would you bother to do this?
post #3 of 22
Thread Starter 
Why would a DAC be pointless?
post #4 of 22
you already have a dac, the Marantz SR7005. It's kinda pointless to add a seperate dac to the mix
post #5 of 22
Thread Starter 
Thanks.But, how does the Marantz utilize the internal DAC when i use a HDMI connection for my Blu-ray(thinking more for CD's than movies)?
post #6 of 22
hdmi is a digital signal. Your bluray player is passing that signal to the AVR and the AVR is processing that signal
post #7 of 22
Quote:
But, how does the Marantz utilize the internal DAC when i use a HDMI connection for my Blu-ray(thinking more for CD's than movies)?
What do you mean, how? That's the way your system works. The digital data must be converted to an analog signal at some point. Using a digital connection like HDMI to your AVR means that the DAC in the AVR is doing the converting.

If you add an ourboard DAC, then the DAC will be doing the converting, and you will use an analog connection between the DAC and the AVR. However, many of the signal processing features of an AVR only work on the digital side, so your AVR will reconvert the analog signal to digital, apply signal processing, and then convert back to analog. There's probably a way to avoid this reconversion, but then you lose all those features, which include room correction and bass management, and possibly more.

And before you ask, no, an outboard DAC will not provide better sound quality. Despite whatever you have read or heard.
post #8 of 22
Quote:
Originally Posted by gelly View Post

Thinking about getting a DAC. My question is when hooking up a Blu-ray player, i need to hook it into the DAC( via optical or Coax) then the Blu-ray back to my AVR(via HDMI)? If this is correct, how does the AVR know to bypass the audio from the HDMI? Is the something i need to set on my AVR(Marantz SR7005) Thanks.

Your AVR has an option called "Direct Playback" that bypassed its internal DACs and also bypasses its speaker management facilities and other valuable features of your AVR.

The DAC or other such source is connected to your AVR via regular analog RCA cables. If you are using a BD player or surround processor with its own surround decoder than far more than just 2 cables are required.

This is described on page 48 and 50 of your owner's manual.

According to its spec sheet on page 118 your AVR's analog facilities only have 96 dB dynamic range (IHF–A weighted, DIRECT mode) which is about the same as a $100 CD player.

Not only does adding an external DAC duplicate something you already bought once with the AVR but the possible advantage of any external DAC that you purchase will be throttled by the weakest link in your system - the analog circuitry of your AVR. Actually, the weakest link is the recordings that you will play through the DAC no matter how many bits they have.
post #9 of 22
The SNR does not tell the whole story. The 7005 AVR has listed a 0.08% THD - that equals -62dB. That is actually 12 bit of resolution. Regardless of how many bits you shove in that AVR, you will get only about 12 bit worth of clean audio output. That is even more audible than the 96SNR...
The reality is that the power amplifier in that DAC is an average consumer-oriented one. better ones have 0.05% THD - it's still only 14 bit of analog signal.
of course, those numbers are valid for nominal power, at lower wattages you might have slightly less distortion - but when you go below 1W you might have again increasing THD.

Try using good headphones instead your AVR.
post #10 of 22
Quote:
Originally Posted by SoNic67 View Post

The 7005 AVR has listed a 0.08% THD - that equals -62dB. That is actually 12 bit of resolution.

Put a cloth over your eyes and your ears won't be able to tell 0.09% from 0.03% THD
post #11 of 22
Besides the fact that lowering the volume does not change the distortion levels, your call is flawed by other aspect: if I do impair my hearing, it doesn't mean that the differences are not there anymore...
What you say is similar with "if an ostrich hides his head in sand, the Sun stops existing". Or with "if a tree falls in a forest and nobody is there to hear it, then it makes no noise".
Edited by SoNic67 - 3/29/13 at 1:18pm
post #12 of 22
Quote:
Originally Posted by SoNic67 View Post

The SNR does not tell the whole story. The 7005 AVR has listed a 0.08% THD - that equals -62dB.

All true, but in general AVR power ratings are taken above the clipping point to obtain more impressive numbers for power output. Below clipping and at typical listening levels the THD is probably more like 0.01-0.02% or less.
post #13 of 22
Quote:
Originally Posted by SoNic67 View Post

Besides the fact that lowering the volume does not change the distortion levels,

That would be highly unusual. On what authority do you make this exceptional claim?
post #14 of 22
On the laws of physics. Linear attenuation (like lowering the volume with a blanket as suggested in the post that I replied to) does not add harmonic distortion.
And no, serious AVR don't list power at clipping levels. Or distortion. Would be amazing to go past clipping and have only 0.05% THD.
The best case scenario of an amplifier gets, as I said, just a little bit lower than nominal THD published. A decent one (Harman Kardon HK 990) goes only as low as 0.005%. That's an awesome -86dB. Still only 14 bit of actual resolution.


Credits: http://www.stereophile.com/content/harman-kardon-hk-990-integrated-amplifier-measurements
Edited by SoNic67 - 3/30/13 at 7:08pm
post #15 of 22
Quote:
Originally Posted by SoNic67 View Post

On the laws of physics. Linear attenuation (like lowering the volume with a blanket as suggested in the post that I replied to) does not add harmonic distortion.

Suggests a faulty model of how audio gear is built and set up.

The attenuators in audio gear always precede the power amplifiers. When you turn the volume down, you turn down the power level that the amplifer operates at.

You aren't even properly interpreting the graph you posted from the HK 990!

It clearly shows that THD+N changes as you change the power output. Don't you know that the volume control changes the power coming out of the output stage?

BTW the odd increase in THD+N as power levels drop below 70 watts is not distortion rising, but noise increasing. The actual nonlinear distoriton probably continues to decrease or remains the same.
Quote:
And no, serious AVR don't list power at clipping levels. Or distortion. Would be amazing to go past clipping and have only 0.05% THD.

That would be unfounded speculation trying to instruct my 40+years on the test bench. ;-)

Please observe the following enlargement of the graph you posted from the HK 990:



The HK990 starts clipping at 250 watts and 0.007% THD as indicated by the beginning of a sharp rise in THD+N

Now, we can play "Pick the power rating" ;-)

200 watts @ 0.065% THD+N
250 watts @ 0.007% THD+N
260 watts @ 0.025% THD+N
270 watts @ 0.1% THD+N
280 watts @ 1% THD+N
post #16 of 22
Quote:
Originally Posted by arnyk View Post

The attenuators in audio gear always precede the power amplifiers. When you turn the volume down, you turn down the power level that the amplifer operates at.
He was NOT talking about attenuators INSIDE equipment, he was talking about putting a blanket on my head - I already quoted that part for you. Pay attention.
Quote:
Originally Posted by arnyk View Post

The HK990 starts clipping at 250 watts and 0.007% THD as indicated by the beginning of a sharp rise in THD+N
Now, we can play "Pick the power rating" ;-)
200 watts @ 0.065% THD+N
250 watts @ 0.007% THD+N
260 watts @ 0.025% THD+N
270 watts @ 0.1% THD+N
280 watts @ 1% THD+N
You can play that, but HK rates the HK 990 at 150W on 8ohm: "150 watts per channel into 8 ohms @ 20Hz – 20kHz, <0.07% THD, both channels driven;". The graph that I did post was for 8 ohm. The distortion is given BEFORE the sharp rise.
The 4 ohm THD that you show is not rated on HK documents.
Edited by SoNic67 - 4/5/13 at 12:49pm
post #17 of 22
Quote:
he was talking about putting a blanket on my head
No one suggested that. This is absurd.

I suspect the suggestion was that you compare components with a blanket over THEM, so that you aren't influenced by your prior knowledge/beliefs.

OTOH, if you want to throw a blanket over your head, I'm sure no one here will object. smile.gif
post #18 of 22
Quote:
Originally Posted by ThumbtackJack View Post

Put a cloth over your eyes and your ears won't be able to tell 0.09% from 0.03% THD

Is this enough proof? You really can't read back what was typed?
post #19 of 22
Uhm, you're failing basic reading comprehension there SoNic.

Let me help you a little by adding a simple comma to his sentence:

"Put a cloth over your eyes, and your ears won't be able to tell 0.09% from 0.03% THD."

WIthout that pause, the sentence would make no sense, just as your interpretation of it makes no sense.
post #20 of 22
Quote:
Originally Posted by SoNic67 View Post

Quote:
Originally Posted by arnyk View Post

The attenuators in audio gear always precede the power amplifiers. When you turn the volume down, you turn down the power level that the amplifer operates at.
He was NOT talking about attenuators INSIDE equipment, he was talking about putting a blanket on my head - I already quoted that part for you. Pay attention.
Quote:
Originally Posted by arnyk View Post

The HK990 starts clipping at 250 watts and 0.007% THD as indicated by the beginning of a sharp rise in THD+N
Now, we can play "Pick the power rating" ;-)
200 watts @ 0.065% THD+N
250 watts @ 0.007% THD+N
260 watts @ 0.025% THD+N
270 watts @ 0.1% THD+N
280 watts @ 1% THD+N
You can play that, but HK rates the HK 990 at 150W on 8ohm: "150 watts per channel into 8 ohms @ 20Hz – 20kHz, <0.07% THD, both channels driven;". The graph that I did post was for 8 ohm. The distortion is given BEFORE the sharp rise.
The 4 ohm THD that you show is not rated on HK documents.

So what?

You seem to have missed my point about the power ratings game often being just a matter of cherry-picking numbers.
post #21 of 22
Quote:
Originally Posted by SoNic67 View Post

Quote:
Originally Posted by ThumbtackJack View Post

Put a cloth over your eyes and your ears won't be able to tell 0.09% from 0.03% THD

Is this enough proof? You really can't read back what was typed?

Looks like a true statement. Where's the beef?
post #22 of 22
Quote:
Originally Posted by arnyk View Post

Quote:
Originally Posted by SoNic67 View Post

On the laws of physics. Linear attenuation (like lowering the volume with a blanket as suggested in the post that I replied to) does not add harmonic distortion.

Suggests a faulty model of how audio gear is built and set up.

The attenuators in audio gear always precede the power amplifiers. When you turn the volume down, you turn down the power level that the amplifer operates at.

You aren't even properly interpreting the graph you posted from the HK 990!

It clearly shows that THD+N changes as you change the power output. Don't you know that the volume control changes the power coming out of the output stage?

BTW the odd increase in THD+N as power levels drop below 70 watts is not distortion rising, but noise increasing. The actual nonlinear distoriton probably continues to decrease or remains the same.
Quote:
And no, serious AVR don't list power at clipping levels. Or distortion. Would be amazing to go past clipping and have only 0.05% THD.

That would be unfounded speculation trying to instruct my 40+years on the test bench. ;-)

Please observe the following enlargement of the graph you posted from the HK 990:



The HK990 starts clipping at 250 watts and 0.007% THD as indicated by the beginning of a sharp rise in THD+N

Now, we can play "Pick the power rating" ;-)

200 watts @ 0.065% THD+N
250 watts @ 0.007% THD+N
260 watts @ 0.025% THD+N
270 watts @ 0.1% THD+N
280 watts @ 1% THD+N

thats not the same graph he posted!!!!!

wow you need an amp to get da clean power with no distortion big mono giga watt amps unlimited reserves of clean power

you got to have da clean power...

if you want da good sound

biggrin.gif
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