janneman said:Will they ever stop?
Witness the new AK4397 32 bit, 196kHz DAC. Phase-perfect digital filter, fully differential analog out without the need for coupling caps, digital level control (32 bits, remeber). Direct interface to 32-bit path outputs from DSP's.
Jan Didden
Jan,
one techincal query,
when designing a 2 pole low pass filter, how critical are the real values used when compared to calculated values, that will affect the cutoff frequencies, and more importantly the phase.
this is most critical when one is using discrete comps rather laser trim SMDs.
any comments, I think you have some experience in this area.
janneman said:Will they ever stop?
digital level control (32 bits, remember).
Jan Didden
Not sure that that gains you all that much. The actual increments or decrements still have to be of a practical size.
Hi David,
I'm curious about all the new DACs. I'd look forward to your opinion about this one.
I've read some of your other posts with interest. It's good to hear that someone actually likes the sound of some of the new DACs. I would hope that some of the new digital technology actually sounds as good or better than non-oversampling DACs. Especially, since I don't know of any non-oversampling DACs for Hi-Rez audio. I can't quite imagine a multichannel home theater processor made with those old old technology DACs.
My hope is that in the future, there's will be a multi-channel processor project here, which will decode and convert every conceiveable format including SACD, DVD-Audio, PCM, 16/24/32 bit 44.1-192KHZ , LPCM, MLP, Dolby True HD, DTS HD Master etc. Will have every conceivable input. SPDIF, optical, HDMI, USB ETC. . .
Have tube and transistor output stages. Be modular. And anything else I've forgotten to include.
This way one project could be built and improved upon by anyone looking make a DAC project. To me this would be better than everyone building many different projects.
I'm curious about all the new DACs. I'd look forward to your opinion about this one.
I've read some of your other posts with interest. It's good to hear that someone actually likes the sound of some of the new DACs. I would hope that some of the new digital technology actually sounds as good or better than non-oversampling DACs. Especially, since I don't know of any non-oversampling DACs for Hi-Rez audio. I can't quite imagine a multichannel home theater processor made with those old old technology DACs.
My hope is that in the future, there's will be a multi-channel processor project here, which will decode and convert every conceiveable format including SACD, DVD-Audio, PCM, 16/24/32 bit 44.1-192KHZ , LPCM, MLP, Dolby True HD, DTS HD Master etc. Will have every conceivable input. SPDIF, optical, HDMI, USB ETC. . .
Have tube and transistor output stages. Be modular. And anything else I've forgotten to include.
This way one project could be built and improved upon by anyone looking make a DAC project. To me this would be better than everyone building many different projects.
janneman said:Will they ever stop?
Witness the new AK4397 32 bit, 196kHz DAC. Phase-perfect digital filter, fully differential analog out without the need for coupling caps, digital level control (32 bits, remeber). Direct interface to 32-bit path outputs from DSP's.
Jan Didden
I've had a couple of these lying around for a few weeks. I just haven't been assed to use them for anything.
dw8083 said:I just received an AKM4397 eval board. I'm hoping to have it hooked up within a week. I'll let folks know how it sounds.
It does include the new National LME49710NA opamps for the active filter.
-David
Active filter? What I understood from the description is that they used a switched cap filter obviating the need for output filters?
Jan Didden
Re: Re: 32-bit DAC
Well you can do the math yourself. Calculate the cut-off freq with the exact design values, then vary the R by, say 1% and/or the C by, say, 5% and see what you get. I don't think it is critical at all. Your cut-off freq may vary a bit, but so what?
Jan Didden
ttan98 said:
Jan,
one techincal query,
when designing a 2 pole low pass filter, how critical are the real values used when compared to calculated values, that will affect the cutoff frequencies, and more importantly the phase.
this is most critical when one is using discrete comps rather laser trim SMDs.
any comments, I think you have some experience in this area.
Well you can do the math yourself. Calculate the cut-off freq with the exact design values, then vary the R by, say 1% and/or the C by, say, 5% and see what you get. I don't think it is critical at all. Your cut-off freq may vary a bit, but so what?
Jan Didden
Re: Re: 32-bit DAC
Well one option would be to take a Behringer DCX2496 dig xover with a 32bit DSP path and interface it directly with this DAC.
Jan Didden
Cauhtemoc said:
I've had a couple of these lying around for a few weeks. I just haven't been assed to use them for anything.
Well one option would be to take a Behringer DCX2496 dig xover with a 32bit DSP path and interface it directly with this DAC.
Jan Didden
janneman said:Will they ever stop?
I look forward to seeing the latest iteration of your volume/output boards.
labjr said:Hi David,
I'm curious about all the new DACs. I'd look forward to your opinion about this one.
I've read some of your other posts with interest. It's good to hear that someone actually likes the sound of some of the new DACs. I would hope that some of the new digital technology actually sounds as good or better than non-oversampling DACs. Especially, since I don't know of any non-oversampling DACs for Hi-Rez audio. I can't quite imagine a multichannel home theater processor made with those old old technology DACs.
My hope is that in the future, there's will be a multi-channel processor project here, which will decode and convert every conceiveable format including SACD, DVD-Audio, PCM, 16/24/32 bit 44.1-192KHZ , LPCM, MLP, Dolby True HD, DTS HD Master etc. Will have every conceivable input. SPDIF, optical, HDMI, USB ETC. . .
Have tube and transistor output stages. Be modular. And anything else I've forgotten to include.
This way one project could be built and improved upon by anyone looking make a DAC project. To me this would be better than everyone building many different projects.
I'm working on a company project that uses a 32 bit DSP in front of a Delta Sigma DAC. It has or will have, the Dolby library, ethernet 802.11 & 802.3, and finally HDMI 1.3. Don't even ask what the licensing costs are.
We have been poking around with wireless HDMI. It works very well. HDMI is great since it overcomes a lot of recording company concerns about pirating since DRM is a component of the spec.
The older DAC chips are simplier and more DIY friendly. Delta Sigma got a bad rap (partially deserved)in the earlier versions.
-David
janneman said:
Active filter? What I understood from the description is that they used a switched cap filter obviating the need for output filters?
Jan Didden
There is still a lot of out of band noise. Although AKM definately does the best job of reducing it. Filtering is still required, and my own experience has had greater success with active filtering to provide more drive to reduce cable sensitivity.
To your point I have seen successful implementations with some Delta Sigma DAC's like the WM8740 with just passive filtering, but the DAC was integrated with a preamp and another had special cabling.
-David
Re: Re: Re: 32-bit DAC
The AK4397 is very nice and all, but there is no reason for 32 bit resolution. The noise floor of 120 dB still swamps everything beyond 20 bits. You would need 256 DACs in parallel to even reach noise floor of 144 dB, which is the limit for 24 bits.
If I'm not mistaken, most sigma delta DACs use a switched capacitor filter.
You got that right.
janneman said:
Well one option would be to take a Behringer DCX2496 dig xover with a 32bit DSP path and interface it directly with this DAC.
Jan Didden
The AK4397 is very nice and all, but there is no reason for 32 bit resolution. The noise floor of 120 dB still swamps everything beyond 20 bits. You would need 256 DACs in parallel to even reach noise floor of 144 dB, which is the limit for 24 bits.
janneman said:
Active filter? What I understood from the description is that they used a switched cap filter obviating the need for output filters?
Jan Didden
If I'm not mistaken, most sigma delta DACs use a switched capacitor filter.
dw8083 said:Although AKM definately does the best job of reducing it.
You got that right.
janneman said:Will they ever stop?
32 bit, 196kHz DAC
Bit depth is probably overkill, i'd like to see 2x the sampling rate (392 kHz)
dave
TheShaman said:
They need to get a new version of the laws of physics out.
Let us ignore thermal noise entirely; there is a fundamental limit from quantum mechanics, given by Planck's constant. This about 6.6x10^-34 Js. If we take a a 0.6microsecond time period (from the sampling rate), the fundamental noise uncertainty energy in a sample is 10^-27J, so the noise power is about 10^-21W
If we set the reference power level at say 1mW (0dBm) this is -180dB. Applying the basic 6dB per bit rule, we find that the maxiumum resolution, for this sampling rate and reference level, is 30bits.
So the claimed figures can be shown to be pure and simple marketing BS.
PigletsDad said:
So the claimed figures can be shown to be pure and simple marketing BS.
Obviously, but I'm really wondering how they came up with those numbers...
Perhaps they add up the Bits and kHz's of all the paralleled DACs?! That would be a new one!
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