I do, I just need to finish TDA1541A version and we will see how it goes 
That being the case I will have 3 DACs for this digital filter (AD1864/AD1865, AD1862 and TDA1541A), but you are free to use the filter with anything else. There is no restrictions to be honest. I will not be assembling DAC boards, so if you want one you will receive schematics and PCB only to assemble it on your own. However, digital filters will be pre-assembled.
That being the case I will have 3 DACs for this digital filter (AD1864/AD1865, AD1862 and TDA1541A), but you are free to use the filter with anything else. There is no restrictions to be honest. I will not be assembling DAC boards, so if you want one you will receive schematics and PCB only to assemble it on your own. However, digital filters will be pre-assembled.
I do, I just need to finish TDA1541A version and we will see how it goes
That being the case I will have 3 DACs for this digital filter (AD1864/AD1865, AD1862 and TDA1541A), but you are free to use the filter with anything else. There is no restrictions to be honest. I will not be assembling DAC boards, so if you want one you will receive schematics and PCB only to assemble it on your own. However, digital filters will be pre-assembled.
you are missing one of the best
please pay attention to pcm1704
I do, I just need to finish TDA1541A version and we will see how it goes
That being the case I will have 3 DACs for this digital filter (AD1864/AD1865, AD1862 and TDA1541A), but you are free to use the filter with anything else. There is no restrictions to be honest. I will not be assembling DAC boards, so if you want one you will receive schematics and PCB only to assemble it on your own. However, digital filters will be pre-assembled.
great stuff, I had my mind precisely around the digital filter for my TDA ... which has already its own pcb. Please, keep us up posted !!. Pre-assembled sounds sweet to me, I would definitely sign up for a filter pcb.
cheers
Pepe
I'm sorry, I did forget to answer your post - I do not plan to design anything with PCM1704 since that DAC is not really my cup of tea.
It's a cheap-made DAC and its abilities are far from its predecessors such as PCM58 and PCM63. It has several faults due to cheap approach such as requirement of 2 extra clocks after latching before the change is visible on its output. It means that its jitter depends on the CLK rather than LE signal which is the case for all other DACs out there (including PCM56, PCM58 and PCM63).
Also, it creates an illusion of having 24 bits which is probably the case why some might prefer it over actual good DACs.
Besides all of that the sound from it is not bad, but is certainly not worth the money it is currently being sold for.
That is my personal opinion on that matter
The devices we have are often made according to the scheme shown in the figure.
The asynchronous version of your filter is included in this scheme only as: LE unchanged, BCK and DATA must be passed bypassing the 574 resynchronization register.
Questions:
1. Will it work?
2. minimum how much BCK is off after LE? Or is there enough time for resynchronization?
3. What is the Edge masterclock on the chip input at LE?
4. Is it possible to expect the appearance of a synchronous / asynchronous version?
When reMCK 768Fs -> BCK 384FS is supported in AD1862 datasheet! PCM61 is also 17 MHz in datasheet!
AD1851 / 61 does not write max in datashit but it will probably work! Colleagues made the NOS version of pcm1702 and report stable operation at high frequencies up to 32x (incorrect
)!Big request - think about the possible introduction of the jumper to the synchronous version !!! and jumper on 8Fs !!! There will be an additional interest in the purchase!
Those who do not have synchronization will switch to asynchronous or pick up fast components, for example, AD1861 is cheap!
Hello
I'm sorry for the delay, but it appears the digital filter is ready It is being tested by several users as well. So far I heard only good opinions about it In fact, a friend of mine did build a small board to put everything on during his tests of the whole set (USB Audio + digital filter + DAC with AD1865):
@andrybelaev
Answering your questions:
1) If you would like to use this digital filter you should remove the whole middle section for that matter. It just creates issues and doesn't solve anything. You are basically re-clocking asynchronously (if 33.8688 MHz clock is running), so that's a really bad idea as well.
2) It should be off at least for 2 cycles of oscillator frequency (depending on the world length which is 16, 18, 20 and 24 => 14 MHz, 15.5 MHz, 17 MHz, 20 MHz accordingly).
3) 768 kHz is the maximum output LE frequency if input is an integer factor of 48 kHz rate.
4) I'm afraid I will not be designing such version since the whole idea of asynchronous operation is to make old R-2R work with high interpolation rate of 705.6 / 768 kHz. Normal synchronous operation* with BCLK rate of 64x does not allow you to run AD1862 at such speed. Even if you run at synchronized 48x Fs (which would require a PLL anyway since such clock frequencies aren't derived from 2^x division) you are still exceeding the specification of AD1862. That being the case the conclusion is it is pointless to run DACs synchronously just for the sake of clocks being synchronous if they were designed to run asynchronously (separate LE and BCLK clock domains).
* Not synchronous in terms of PLL locking into the input frequency, but rather standardized BCLK of 64x Fs which is halved when clocking into the DAC chip (so 32x Fs).
I'm sorry for the delay, but it appears the digital filter is ready
It is being tested by several users as well. So far I heard only good opinions about it In fact, a friend of mine did build a small board to put everything on during his tests of the whole set (USB Audio + digital filter + DAC with AD1865):An externally hosted image should be here but it was not working when we last tested it.
@andrybelaev
Answering your questions:
1) If you would like to use this digital filter you should remove the whole middle section for that matter. It just creates issues and doesn't solve anything. You are basically re-clocking asynchronously (if 33.8688 MHz clock is running), so that's a really bad idea as well.
2) It should be off at least for 2 cycles of oscillator frequency (depending on the world length which is 16, 18, 20 and 24 => 14 MHz, 15.5 MHz, 17 MHz, 20 MHz accordingly).
3) 768 kHz is the maximum output LE frequency if input is an integer factor of 48 kHz rate.
4) I'm afraid I will not be designing such version since the whole idea of asynchronous operation is to make old R-2R work with high interpolation rate of 705.6 / 768 kHz. Normal synchronous operation* with BCLK rate of 64x does not allow you to run AD1862 at such speed. Even if you run at synchronized 48x Fs (which would require a PLL anyway since such clock frequencies aren't derived from 2^x division) you are still exceeding the specification of AD1862. That being the case the conclusion is it is pointless to run DACs synchronously just for the sake of clocks being synchronous if they were designed to run asynchronously (separate LE and BCLK clock domains).
* Not synchronous in terms of PLL locking into the input frequency, but rather standardized BCLK of 64x Fs which is halved when clocking into the DAC chip (so 32x Fs).
OK, I might take two boards.
How about a version in: I2S / out: 2x I2S balanced L/-L and R/-R @384kHz (e.g. balanced TDA1387, TDA1543, etc.etc. ? I'd take two of these boards as well.
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@lindamar
I do not believe there will be a GB because this digital filter is hand assembled and it simply takes time and several tests after the assembly. It's definitely time consuming project even despite being quite simple in terms of amount of components.
The spin-off version for TDA1540/TDA1541 is not ready yet. I need to test it thoroughly with music reproduction to make sure everything is correct since it's a different format and different interpolation ratio. I do not plan to add output I2S for that matter.
@weissi
@Luke
You guys might want to hold on for a while since I need to finish TDA1541A version
@merlin el mago
You can find the price in the first post. It's a hand assembled digital filter and I don't have any ready ones available right now (I did build around 15 and practically all of them were reserved by diyers from my own country even before the project was finished). However, I will be assembling a few ones sooner than later, so if you wish you can hold on and I will let you guys know when it will be ready.
I do not believe there will be a GB because this digital filter is hand assembled and it simply takes time and several tests after the assembly. It's definitely time consuming project even despite being quite simple in terms of amount of components.
The spin-off version for TDA1540/TDA1541 is not ready yet. I need to test it thoroughly with music reproduction to make sure everything is correct since it's a different format and different interpolation ratio. I do not plan to add output I2S for that matter.
@weissi
@Luke
You guys might want to hold on for a while since I need to finish TDA1541A version
@merlin el mago
You can find the price in the first post. It's a hand assembled digital filter and I don't have any ready ones available right now (I did build around 15 and practically all of them were reserved by diyers from my own country even before the project was finished). However, I will be assembling a few ones sooner than later, so if you wish you can hold on and I will let you guys know when it will be ready.