Digital Source?
I'm thinking of using PC / dedicated streaming source for the dam1021. Should I worry about the USB source signal quality if I were to interface it with Amanero Combo384 and use IIS to dam1021?
It seems to me that the main concern with USB signal is the jitter. Would the reclocking on dam1021 eliminate the issues with mediocre USB outputs?
I might consider using an RPi to have remote control capabilities. Is there a better option for source quality-wise?
Thanks in advance!
I'm thinking of using PC / dedicated streaming source for the dam1021. Should I worry about the USB source signal quality if I were to interface it with Amanero Combo384 and use IIS to dam1021?
It seems to me that the main concern with USB signal is the jitter. Would the reclocking on dam1021 eliminate the issues with mediocre USB outputs?
I might consider using an RPi to have remote control capabilities. Is there a better option for source quality-wise?
Thanks in advance!
It depends on who you ask
In theory, the dam1021's built-in re-clocking should address all but the absolute worst inputs. However, I've read a few subjective impression posts where people state they have an improvement from better inputs (e.g. for USB, upgrade Amanero to latest-gen Xmos; for RPi, add a Kali reclocker).If you already have an Amanero, this is probably the easiest way to start. There are lots of people using this exact setup; it's how I started with my dam1021. It's a straightforward approach, well documented in this thread, and definitely not a bad way to go by any means.
That's my preference, though it's not really about sound quality, it's just more convenient for my setup. I.e., I'd rather have a "music server" than just a standalone DAC.
I do have a Kali reclocker for RPi, though I haven't yet tried it with my dam1021. I'm working on rebuilding my dam1021 currently, but as a last step, I do plan to see if I can hear a difference with or without the Kali.
Enjoy!
More questions on build
Thanks! Amanero is also much cheaper and easier to find than the latest gen XMOS..
I'm new to this type of forums so please forgive my ignorance.... Is there a better way to find / compile information from this thread other than searching? It seems kind of hard to find documentation for a particular component, e.g. USB interface, without knowing the exact part used beforehand...
My current plan is, use AZ Lite controller to communicate with FPGA, since it's got quite a few nice functionalities and I might just use it as a standalone DAC for my phone and laptop for now. Amanero for USB, and quality SPDIF and Coaxial since they're pretty generic and well-documented.
The hard part seems to be power. It appears to me that quality 9V DC for dam1021 and 5V / 3.3V for interfaces are the best options.. But not sure what's good enough / slightly-overkill-just-to-be-safe for this project. Also, would it be wise to use MeanWell 12V/5V DC supplies since they were used in 1541?...
Vref caps still seem to be relevant in rev4 so I'll probably do that too...
Any suggestions on best practices? It would be so nice if we can start a wiki page to share what we've found/learned in the thread... If some people have notes it would be a great starting point... going through 700 pages of discussion really isn't an option....
Thanks, that would be very helpful to us! I'm guessing that there would be no difference as long as you power the USB-IIS interface independently from signal source... Don't see a reason to doubt digital reclocking...
It depends on who you ask
If you already have an Amanero, this is probably the easiest way to start. There are lots of people using this exact setup; it's how I started with my dam1021. It's a straightforward approach, well documented in this thread, and definitely not a bad way to go by any means.
Thanks! Amanero is also much cheaper and easier to find than the latest gen XMOS..
I'm new to this type of forums so please forgive my ignorance.... Is there a better way to find / compile information from this thread other than searching? It seems kind of hard to find documentation for a particular component, e.g. USB interface, without knowing the exact part used beforehand...
My current plan is, use AZ Lite controller to communicate with FPGA, since it's got quite a few nice functionalities and I might just use it as a standalone DAC for my phone and laptop for now. Amanero for USB, and quality SPDIF and Coaxial since they're pretty generic and well-documented.
The hard part seems to be power. It appears to me that quality 9V DC for dam1021 and 5V / 3.3V for interfaces are the best options.. But not sure what's good enough / slightly-overkill-just-to-be-safe for this project. Also, would it be wise to use MeanWell 12V/5V DC supplies since they were used in 1541?...
Vref caps still seem to be relevant in rev4 so I'll probably do that too...
Any suggestions on best practices? It would be so nice if we can start a wiki page to share what we've found/learned in the thread... If some people have notes it would be a great starting point... going through 700 pages of discussion really isn't an option....
Thanks, that would be very helpful to us! I'm guessing that there would be no difference as long as you power the USB-IIS interface independently from signal source... Don't see a reason to doubt digital reclocking...
It depends on who you ask
Thanks to my insomnia, I now understand that the problem with the USB receiver is not a contrived one
Guess we'll really have to figure out what is polluting the signal, whether it's 1)power to USB receiver, 2)poor isolation from source ground/power, 3)difference in USB to IIS conversion for different chips, or 4)clock jitter somehow passed through dam1021 FIFO.1) should be easy to deal with. Intona seems to be one expensive solution to 2), not sure why it's more difficult than replacing the incoming power and ground with something reliable, but I hope that a cheap and simple solution is possible. 3) might need more investigating, but I'm skeptical of differences in conversion. To me intuitively, the chip should just be a function, even one that's one-to-one. 4) seems highly unlikely to Soren, and my intuition says the same.
Hope this helps, really looking forward to getting USB to play nicely with everything else
Sometimes a generous person steps up and creates a wiki that attempts to consolidate info for big threads like this. But, I don't believe anyone has done this for the dam1021. So searching/skimming is unfortunately your best option. You've probably already seen this, but if not, HiFiDUINO has a lot of great info on the dam1021; same goes for DimDim's blog.
From what I've seen, power is all over the map. The DIYINHK lt3042 regulators seem to fairly common; I've used them myself in this role. I'll be using Salas BIB shunt regs in my rebuild (mainly because I've been sitting on them unused for a year now). If you go back a bit in this thread, you can see where one or two guys completely removed all the dam1021's on-board regulators and provided power with A123 26650 batteries. If I didn't already have the Salas regs, I'd probably use the Sigma22 for the dam1021 (I've used the one-pole sigma11 version in the past for other projects).
If I'm not mistaken, I believe for the 1541, the Meanwell SMPSes are used only as a starting point; there is extra regulation and/or filtering between the Meanwells and whatever circuit uses that power.
One more question for now..
Thanks! I didn't know the second one existed - lots of crazy diy there! I gave my build some more thought and depending on how much time I end up having I might just do USB input only since it'll be my main use case. But in any case, if I'm allowed to, I'll be more than happy to start a wiki page when I start building. It shouldn't be that difficult as there are well-defined sections of work, and it could end up being awesome for newcomers if everyone could add to it in a wiki fashion. Hopefully I keep my promise!
Thanks for the info and suggestion! Sigma22 looks solid and I'll go with that.
One more question... Would it be a good idea to power the XMOS from the sigma22 9V DC? Or do I need like a completely separate transformer + regulator to get reasonably clean power and not mess up the dam1021 power? Similarly, if I were to include a toslink/coaxial, should I take power from dam1021 or an independent source? Sorry it's quite a basic question.. but just want to be sure since power seems to matter a lot for the USB receiver.
Yeah there does seem to be filtering by the MWs in the photo... Probably not the best idea for us to go that route.
Thanks! I didn't know the second one existed - lots of crazy diy there! I gave my build some more thought and depending on how much time I end up having I might just do USB input only since it'll be my main use case. But in any case, if I'm allowed to, I'll be more than happy to start a wiki page when I start building. It shouldn't be that difficult as there are well-defined sections of work, and it could end up being awesome for newcomers if everyone could add to it in a wiki fashion. Hopefully I keep my promise!
Thanks for the info and suggestion! Sigma22 looks solid and I'll go with that.
One more question... Would it be a good idea to power the XMOS from the sigma22 9V DC? Or do I need like a completely separate transformer + regulator to get reasonably clean power and not mess up the dam1021 power? Similarly, if I were to include a toslink/coaxial, should I take power from dam1021 or an independent source? Sorry it's quite a basic question.. but just want to be sure since power seems to matter a lot for the USB receiver.
Yeah there does seem to be filtering by the MWs in the photo... Probably not the best idea for us to go that route.
@soekris
I'm thinking of changing the output buffer of Rev.1 board from LME49724 to OPA1632.
Did you ever test an opa1632 in a Rev.1 board?
I'm expecting more output power to drive my headphone (Beyerdynamic DT 1990 Pro with balanced connection).
It's quite good with LME49724 but a little more power would be nice.
THX for a short answer.
Greetings Arnd
I'm thinking of changing the output buffer of Rev.1 board from LME49724 to OPA1632.
Did you ever test an opa1632 in a Rev.1 board?
I'm expecting more output power to drive my headphone (Beyerdynamic DT 1990 Pro with balanced connection).
It's quite good with LME49724 but a little more power would be nice.
THX for a short answer.
Greetings Arnd
I have never tested an opa1632, but it should probably work, they're pretty close, the opa1632 is just faster which might result in stability problems....
But with the 250 ohms DT1990 you need more output voltage, you really should just increase the gain in the buffer, see schematics posted early in the thread....
Eeeh, I don't believe you can do it like that.... My recommendation is to increase the 1.24K feedback resistors from the LME49724 outputs, they set the gain.
I assume you are using a Raspberry Pi? then without ALSA patch and 19.2Mhz clock you will be limited to 192Khz.
I have everything lined up and wired on paper, and will put it together in the next couple of weeks. I'm curious about dual-mono though, because if my current layout works (215*228*70 case), I might be able to just add another 1021 on top of the first without adding new components. Sounds nice and I found great info on this thread, a few more questions:
(1) Soren mentioned there will be micro second misalignments (suppose a parallel I2S connection), will this be a problem and could this be improved further?
(2) I'll be using Audiozen's SK Lite to control the 1021, what would it take to get daisy chaining serials to work here? Is there an existing solution like modding firmware?
(3) I have an independent power 3.3v 200mA to power the I2S isolation chip, were I to stack two 1021s, would this be enough power?
Thanks in advance!
(1) Soren mentioned there will be micro second misalignments (suppose a parallel I2S connection), will this be a problem and could this be improved further?
(2) I'll be using Audiozen's SK Lite to control the 1021, what would it take to get daisy chaining serials to work here? Is there an existing solution like modding firmware?
(3) I have an independent power 3.3v 200mA to power the I2S isolation chip, were I to stack two 1021s, would this be enough power?
Thanks in advance!
Did some more searching, and realized:
(1) Soren mentioned that there's a digital PLL preventing clock drift over time. With this in mind, the micro seconds delay will be inconsequential - more so than moving one side of the headphone or one speaker closer 1mm (3 micro seconds).
(2) Seems like a connection diagram has already been provided, ignore one TX from 1021 and add 1k resistors to RXs.
(3) Still unresolved...
I also noticed that there is a wiki page here for Soekris R2R DAC, but speaking from experience I'm pretty sure it won't useful for noobs like myself. I'm still focused on the build but will try to add to it in the next few weeks. Probably implementation focused but also a more solid starting point for people who have no idea what to put together. Please let me know if you think such an effort would be redundant...
Thanks, everyone!!