--thanks Hyldal for precision.
PCM1794 seems to support I2s input.
--thanks aparatusonitus
I already know this link. My point was about to use simplier glue logic than doing the universal shift register depicted. What Whatsup mentioned ( one inverter and 2x DAC, right justified operation) should be easier to try.
PCM1794 seems to support I2s input.
--thanks aparatusonitus
I already know this link. My point was about to use simplier glue logic than doing the universal shift register depicted. What Whatsup mentioned ( one inverter and 2x DAC, right justified operation) should be easier to try.
Hi Hyldal,
Eric
PCM1792 and PCM1796 integrates an 8x oversampling digital filter. Are you sure that you can bypass this filter and use as NOS DAC?Hyldal said:Does anybody know how to use a BB1792 or BB1796 as NOS. I would like to find a 24 bit converter that are cheaper then the BB1704.
Eric
Hi´Eric.
I dont know right now if the oversampling filter can be omitted, but I will go through the datasheet when I find the time!
I am also open to other DAC´sm only I would like a good cheaper type and a more available type that the 1704 and the obsolite types that normally are used for NOS DAC´s.
I dont know right now if the oversampling filter can be omitted, but I will go through the datasheet when I find the time!
I am also open to other DAC´sm only I would like a good cheaper type and a more available type that the 1704 and the obsolite types that normally are used for NOS DAC´s.
Hi Hydal,
I ask to my question : Yes you can bypass internal digital filter.
See page 38 from PCM1792A datasheets. (see picture link)
With DFMS=1 you need shift register for bit alignment.
With DFMS=0 you don't need shift register.
WDCK (word clock) coming from DIR = Fs (44.1KHz, 96KHz, 192 KHz). PCM1792A needs 1/4Fs or 1/8Fs.
PCM1792A accept right-justified 16bit, 20bit, 24bit audio data.
Eric
I ask to my question : Yes you can bypass internal digital filter.
See page 38 from PCM1792A datasheets. (see picture link)
With DFMS=1 you need shift register for bit alignment.
With DFMS=0 you don't need shift register.
WDCK (word clock) coming from DIR = Fs (44.1KHz, 96KHz, 192 KHz). PCM1792A needs 1/4Fs or 1/8Fs.
PCM1792A accept right-justified 16bit, 20bit, 24bit audio data.
Eric
Attachments
Understand that word clock (WDCK) signal must be operate at 8x or 4x the desired sampling frequency Fs.Eric Juaneda said:...PCM1792A needs 1/4Fs or 1/8Fs...
Eric
Attachments
Hyldal said:Alright, good job Eric!
I will have to se how it can be put together with a DIR IC, Just as simple as with the BB1704.
I am considering CS8420 for DIR.
Hey, you did this dac in the end?
How did it sound?
Eric Juaneda said:The BB DF1704 ou DF1706 are upsampling digital filter. Title of thread is 'NOS 24 Bit DAC'. Upsampled or not upsampled? What kind of project is in the scope
Eric
We are talking about the PCM1704 dac, in which the upsampling filter can easily be disabled.
PCM1704
Sorry for misunderstanding!
There is no upsampling filter in PCM1704, nothing to disable.
Eric
Telstar said:We are talking about the PCM1704 dac, in which the upsampling filter can easily be disabled.
Sorry for misunderstanding!
There is no upsampling filter in PCM1704, nothing to disable.
Eric
Re: PCM1704
Also my mistake. I was thinking of commercial dacs that all have a filter along with the pcm1704 that i planned to remove/disable.
Eric Juaneda said:
Sorry for misunderstanding!
There is no upsampling filter in PCM1704, nothing to disable.
Eric
Also my mistake. I was thinking of commercial dacs that all have a filter along with the pcm1704 that i planned to remove/disable.
Re: Re: PCM1704
Wouldn't it be easier to build one from scratch ?
Telstar said:
Also my mistake. I was thinking of commercial dacs that all have a filter along with the pcm1704 that i planned to remove/disable.
Wouldn't it be easier to build one from scratch ?
Re: Re: Re: PCM1704
Maybe yes, maybe not. It depends on the quality of the components and the layout.
I'm considering the Borbely kits, to diy, and also this dac:
http://www.docet-lector.com/dc224.htm
to mod a bit, disabilng all filters. Done that, it's basically ready. the construction is modular, hence easily modifiyable and the psu and the (tube) output stage are already good, but not SOTA.
OK, its 4 1704 and not 8, but that would be SOTA and would require a LOT more work, starting from scratch or almost.
It's a pity that this chip, which is the only 24 bit R2R dac has been neglected so much from diyers, only reason being cost.
rfbrw said:
Wouldn't it be easier to build one from scratch ?
Maybe yes, maybe not. It depends on the quality of the components and the layout.
I'm considering the Borbely kits, to diy, and also this dac:
http://www.docet-lector.com/dc224.htm
to mod a bit, disabilng all filters. Done that, it's basically ready. the construction is modular, hence easily modifiyable and the psu and the (tube) output stage are already good, but not SOTA.
OK, its 4 1704 and not 8, but that would be SOTA and would require a LOT more work, starting from scratch or almost.
It's a pity that this chip, which is the only 24 bit R2R dac has been neglected so much from diyers, only reason being cost.
rfbrw said:For Borbely's prices, I'd definitely build my own. It is a lot to pay for parts you don't really want.
I'll see if i can get only the parts i need (i.e i dont need balanced, and any filter). if i was able to build everything from sctatch i would have already done.
either case i'm around 2k euros.
Telstar said:
I'll see if i can get only the parts i need (i.e i dont need balanced, and any filter). if i was able to build everything from sctatch i would have already done.
either case i'm around 2k euros.
To modify the Borbely board to that extent would probably make it more expensive. The closest to what you are after I can think of is the output stage of the Tentlabs CD Player. Every other possibility would need extensive modification. Then again I am not the greatest fan of NOS, so there are others better placed to help you.
rfbrw said:
To modify the Borbely board to that extent would probably make it more expensive. The closest to what you are after I can think of is the output stage of the Tentlabs CD Player. Every other possibility would need extensive modification. Then again I am not the greatest fan of NOS, so there are others better placed to help you.
Thanks, rfbrw.
Will look more into it and ask Guido.
I'm not against OS, but i hate sigma-delta and digital filters.
Building a (good) DAC is not easy. There is more than one hundred points to observe to reach this goal. Digital filter is only one of these point.
Have you experience in that design?
Since last years I have chance to listen at home many DAC like Audiosynthesis DAX or Wadia Digimaster X64... They sounds great.
Since few month I listen music with my personal NOS DAC (only prototype at this time). Personally, I prefer NOS DAC, because each digital filter has it's own coloratura. For information, this proto is made with two boards: digital decoder and analog DAC.
Digital decoder allow 16bit, 18bit, 20bit or 24bit resolution with or without audio master clock. This board allow you to made your own analog stage with many DAC like PCM1704, PCM56, PCM1702, AD1851, AD1861, AD1866...
I think this board will be available for sale on 2009.
Don't reduce DAC to its digital filter only.
Eric
Have you experience in that design?
Since last years I have chance to listen at home many DAC like Audiosynthesis DAX or Wadia Digimaster X64... They sounds great.
Since few month I listen music with my personal NOS DAC (only prototype at this time). Personally, I prefer NOS DAC, because each digital filter has it's own coloratura. For information, this proto is made with two boards: digital decoder and analog DAC.
Digital decoder allow 16bit, 18bit, 20bit or 24bit resolution with or without audio master clock. This board allow you to made your own analog stage with many DAC like PCM1704, PCM56, PCM1702, AD1851, AD1861, AD1866...
I think this board will be available for sale on 2009.
Don't reduce DAC to its digital filter only.
Eric
Eric Juaneda said:Building a (good) DAC is not easy. There is more than one hundred points to observe to reach this goal. Digital filter is only one of these point.
Have you experience in that design?
No, that's why I'm looking at some (modular) design that meets my needs. So far the Borbely comes the closest.
Since few month I listen music with my personal NOS DAC (only prototype at this time). Personally, I prefer NOS DAC, because each digital filter has it's own coloratura. For information, this proto is made with two boards: digital decoder and analog DAC.
Hmm... The typical design i saw is 1-receiver board (with eventual filter and src - i dont want neither) 2-dac, 3-output stage.
Digital decoder allow 16bit, 18bit, 20bit or 24bit resolution with or without audio master clock. This board allow you to made your own analog stage with many DAC like PCM1704, PCM56, PCM1702, AD1851, AD1861, AD1866...
I think this board will be available for sale on 2009.
Which input format will accept? I'm looking for either ADAT or AES/EBU.
Make it support several pcm1704 (at least 4 per channel) and you may have a customer
Don't reduce DAC to its digital filter only.
Absolutely not, but that is the first step on the signal, isnt it?
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