I'm looking at high end DAC, streamer & DSP for my system but unsure of the best approach. I'm open to self build options and/or buying off the shelf components, would welcome peoples thoughts and opinions.
Options range from a single PC device running Streamer with DSP and DAC as well, or off-the shelf DAC with PC based Streamer + PC DSP, or instead all 3 components could be off the shelf.
I don't know if there are any DIY non-pc based DAC options which are viable for high end, but I'm wondering if a DIY DAC chip per channel (L+R + each sub), might be something to consider. I'm think this from an active speaker with combined DAC architecture approach, not plate power amp but more a co-located power amp + DAC with short speaker cable run (I hate lots of cable everywhere and will avoid it if I can).
Main benefit of a PC based DSP would be number of taps available, which if I understand correctly will mean that a PC based DSP solution "should" be the highest quality DSP option available.
Challenges
1. Noise - I'm concerned about EMI/RFI generation & injection into the audio chain when using a PC. Other than building a high quality isolation case, are low noise PSUs available for PCs, what about low noise components?
2. USB - for streamer to DAC the USB interface would appear to be the best choice, but how to isolate the USB correctly and provide the right filtering?
3. Not sure what practical options exist in a PC to ensure high quality clocking
4. I'm not yet sure about reclocking e.g. Mutec, but it could be an option to try at some point, would this be workable with PC streamer/DAC?
to illustrate just how much I overthink these kind of things, I've currently retrofitted 8mm aluminium plate into my streamer along with sheets of noise absorption material to isolate from external noise, noise from the PSU and noise between the boards, it's clear to me that this provides an improvement.
Whatever solution I go for I'm highly likely to make 10mm custom cases for some (all) of these key components with separate cases for high quality PSUs - this would likely apply to rehousing off the shelf equipment if I don't go down a DIY route.
I'm sure some people will think I'm crazy
given the cost & effort of doing things like this I personally think the attention to detail is worth it.
my insanity knows no bounds!
Options range from a single PC device running Streamer with DSP and DAC as well, or off-the shelf DAC with PC based Streamer + PC DSP, or instead all 3 components could be off the shelf.
I don't know if there are any DIY non-pc based DAC options which are viable for high end, but I'm wondering if a DIY DAC chip per channel (L+R + each sub), might be something to consider. I'm think this from an active speaker with combined DAC architecture approach, not plate power amp but more a co-located power amp + DAC with short speaker cable run (I hate lots of cable everywhere and will avoid it if I can).
Main benefit of a PC based DSP would be number of taps available, which if I understand correctly will mean that a PC based DSP solution "should" be the highest quality DSP option available.
Challenges
1. Noise - I'm concerned about EMI/RFI generation & injection into the audio chain when using a PC. Other than building a high quality isolation case, are low noise PSUs available for PCs, what about low noise components?
2. USB - for streamer to DAC the USB interface would appear to be the best choice, but how to isolate the USB correctly and provide the right filtering?
3. Not sure what practical options exist in a PC to ensure high quality clocking
4. I'm not yet sure about reclocking e.g. Mutec, but it could be an option to try at some point, would this be workable with PC streamer/DAC?
to illustrate just how much I overthink these kind of things, I've currently retrofitted 8mm aluminium plate into my streamer along with sheets of noise absorption material to isolate from external noise, noise from the PSU and noise between the boards, it's clear to me that this provides an improvement.
Whatever solution I go for I'm highly likely to make 10mm custom cases for some (all) of these key components with separate cases for high quality PSUs - this would likely apply to rehousing off the shelf equipment if I don't go down a DIY route.
I'm sure some people will think I'm crazy
given the cost & effort of doing things like this I personally think the attention to detail is worth it.my insanity knows no bounds!
What operating system do you plan on using?
The computing power needed, even for FIR filters, is not all that high. No need to go overboard in that regard. On the other hand, a "silent PC" is probably what you want, e.g. using only passive heat sink(s) integrated into the case, often in a miniITX form factor. Have you looked into these kind of "fanless" PC products?
There is no "high quality clocking" in a PC in the sense that you may be used to in audio circles. What you have is the local PC clock, which is anything but "high quality" compared to hardware based DSP processors, DACs, etc. But that is really not an issue, and I don't know why people are so obsessed with it, honestly. The clock(s) that are important are in the DAC (and ADC if you are using one). Inside the PC and over USB, samples are passed around as "buffered data chunks" and clocks/jitter are irrelevant. Getting the highest sound quality and lowest noise and hum is most important, and this totally depends on what is converting the audio data into a usable (e.g. analog) audio signal.
The computing power needed, even for FIR filters, is not all that high. No need to go overboard in that regard. On the other hand, a "silent PC" is probably what you want, e.g. using only passive heat sink(s) integrated into the case, often in a miniITX form factor. Have you looked into these kind of "fanless" PC products?
There is no "high quality clocking" in a PC in the sense that you may be used to in audio circles. What you have is the local PC clock, which is anything but "high quality" compared to hardware based DSP processors, DACs, etc. But that is really not an issue, and I don't know why people are so obsessed with it, honestly. The clock(s) that are important are in the DAC (and ADC if you are using one). Inside the PC and over USB, samples are passed around as "buffered data chunks" and clocks/jitter are irrelevant. Getting the highest sound quality and lowest noise and hum is most important, and this totally depends on what is converting the audio data into a usable (e.g. analog) audio signal.
There are many cheap fanless “mini PC” devices available. For instance I use a Celeron N3450 based one to drive my home made active system using an Equaliser APO FIR crossover with biquad driver/ box/ room EQ. In iterms of electrical noise, these low power fanless PCs use a double insulated power supply (no safety ground) and as long as you use them headless there is no opportunity for ground loops. I’m also using an asynchronous USB DAC interface to avoid using the PC as a clock source.
Not too fused which OS, windows a preference but Linux is fine too.
I should have been a bit clearer on clocking, I'm making a distinction between the DACs sampling clock and the USB data sync clock.
I guess the clocking then depends on how the DAC & streamer are built (all in 1 PC versus off the shelf), I've not looked too much into PC DAC builds, I assumed the DACs sample clock will be on a dedicated DAC card in the PC rather than using the PCs own clock (which is very poor) - not sure how good these PC DACs compare against dedicated units but the reason for considering them is exactly as you mention, you have all the data transferring internally in the PC before it hits the DAC so data transmission clocking isn't an issue (presumably), it's just the DAC sampling clock that matters.
If however you separate out the streamer and the DAC then I think the USB transmission clock might be a consideration because as you've already pointed out the PCs clock is pretty poor - I have no idea how big a deal this is to be honest! Think there's debate on things generally on the best approach here, but I might at least like to option to try different things to see for myself.
Silent running is a given, I've built silent PCs before, but it's not the noise floor that worries me, it's EMI/RFI.
I was thinking of a self build of something like this
Reference audiophile music server FC5 - PPA Studio Paul Pang | AudioPC.Shop
however I think it's overkill....
I suspect you can achieve something just as good from a sound quality perspective by going down the mini PC route + USB DAC route that you describe. The question is then what's the right approach i.e. can you just make sure you have a low noise linear PSU in the PC with filtering on the USB, then hook it up to a great USB based DAC (potentially battery powered).
What PC USB card options are there to ensure very low jitter?
You might get inspiration from these products (good company by the way):
Silent Media PCs
There is no need to spend thousands of dollars/euros!
With a powered USB DAC or audio interface, the computer power supply is completely separate from the PS in the DAC. USB should be isolated as well. You should be able to look up reviews that do SINAD testing of DACs and other units to get data that you can use to choose based on needs, budget, etc.
If your source is on file, the computer/NAS will bring data in and buffer it (seconds of it, probably) so that it is waiting to be processed and than spooled out to the DAC as needed. Up until the DAC I do not see a need to "clock" the data stream.
As far as EMI goes unless you stack the DAC on the computer I highly doubt that will be an issue (at all). Use prudent cable routing after the DAC. A run of USB can easily reach over 1m, and so you can just put some distance between the computer and the DAC. Measurements will tell you whether this matters or not.
Silent Media PCs
There is no need to spend thousands of dollars/euros!
With a powered USB DAC or audio interface, the computer power supply is completely separate from the PS in the DAC. USB should be isolated as well. You should be able to look up reviews that do SINAD testing of DACs and other units to get data that you can use to choose based on needs, budget, etc.
If your source is on file, the computer/NAS will bring data in and buffer it (seconds of it, probably) so that it is waiting to be processed and than spooled out to the DAC as needed. Up until the DAC I do not see a need to "clock" the data stream.
As far as EMI goes unless you stack the DAC on the computer I highly doubt that will be an issue (at all). Use prudent cable routing after the DAC. A run of USB can easily reach over 1m, and so you can just put some distance between the computer and the DAC. Measurements will tell you whether this matters or not.
It depends on how far you want to go down the diy route. My probably overkill low noise low jitter solution involves:
1) Avoiding a ground loop between the PC and the DAC/Amp by using a double insulated PC as described above
2) Disconnecting the USB +5v from the PC to the USB interface and providing my own low noise linear +5v supply to the USB interface
3) Using an asynchronous USB interface (in my case a Mini DSP Usbstreamer)
4) Providing a low jitter clock source with its own dedicated low noise linear power supply to drive both the asynchronous USB interface and the DACs
5) Providing the DACs with their own dedicated linear power supplies for both the analog and digital elements
5) Using balanced signal connections between the DACs and Amps to enable the amps to reject any residual common ground noise
This is all home built with the exception of the PC and the USbstreamer, though.
1) Avoiding a ground loop between the PC and the DAC/Amp by using a double insulated PC as described above
2) Disconnecting the USB +5v from the PC to the USB interface and providing my own low noise linear +5v supply to the USB interface
3) Using an asynchronous USB interface (in my case a Mini DSP Usbstreamer)
4) Providing a low jitter clock source with its own dedicated low noise linear power supply to drive both the asynchronous USB interface and the DACs
5) Providing the DACs with their own dedicated linear power supplies for both the analog and digital elements
5) Using balanced signal connections between the DACs and Amps to enable the amps to reject any residual common ground noise
This is all home built with the exception of the PC and the USbstreamer, though.
If you feel good about your build and are satisfied with it, then you have undoubtedly created a nice DIY system. But let me comment on your points regarding the mods and tweaks you implemented. My comments are made under the assumption that the end user is buying not building their gear, which I assume will be the case for user Phobic:
1) A good commercial USB interface will isolate the USB data portion of the unit from the DAC/output portion.
2) Ditto on this
3) Yes, of course this will be best. An async DAC has its own clock for playback, that is totally independent from anything going on in the PC. This is not unique or rare for high quality audio DACs, and you can even get this in some cheap DACs.
4) A good DAC should already have a low jitter clock. Again, there are reviews with measurements available (e.g. online) of DACs that can show you how much jitter is present. Anyway, jitter is totally overrated these days, much like distortion. At some point, lower is not getting you anything, since it is already too low to matter.
5) Again, you can get this out of the box, so unless you are building your own DAC it's all a matter of researching the DAC performance before buying.
6) This is not a bad idea, except that you might not know that balanced lines can be (are inherently) noisier than unbalanced ones, however, they can be better at rejecting hum and noise induced by external EMF. So whether this will have an impact on your setup or not will depend on a variety of factors. If you can locate the DAC next to the amps and away from the computer, a balanced line might not gain you anything at all. At worst it will be noisier by 14dB (ref: Doug Self, The Design of Active Crossovers, p467) and at best only a few dB more noisy.
None of my comments are trying to diminish what you have done adf, but only to point out that many of those features can be had in commercial offerings if you are careful and do your research before buying. Also, it is more about what is going on with the DAC, outside the computer itself.
A couple commercial multi-channel dac options:
ESI - GIGAPORT eX
Okto Research
This could be incorporated with a Raspberry Pi:
HiFiBerry DAC+ DSP | HiFiBerry
Thin client PCs can be silent and cheap. I got a HP t610 used for $40 and added a SATA SSD plus more RAM. Windows 10 or many different Linux distros can be installed.
ESI - GIGAPORT eX
Okto Research
This could be incorporated with a Raspberry Pi:
HiFiBerry DAC+ DSP | HiFiBerry
Thin client PCs can be silent and cheap. I got a HP t610 used for $40 and added a SATA SSD plus more RAM. Windows 10 or many different Linux distros can be installed.
The Gigaport is USB powered. I would avoid that when you can get a DAC with its own independent power supply.
The Okto DAC is an excellent, top notch, product. Note that the only inputs apart from USB are AES/EBU (similar to, but different than, toslink). It can do DSP internally using a C-based language and macros. Expensive and not always available (they make them in small batches).
The HiFiBerry is not a high end solution IMHO.
If you would like a multichannel DAC, I suggest you look at self-powered USB pro audio interfaces such as the Scarlett or Clarett lines from Focusrite, the MOTU M4 (great even without an external PS), and even the Behringer UMC1820 (but not other models from that brand).
The Okto DAC is an excellent, top notch, product. Note that the only inputs apart from USB are AES/EBU (similar to, but different than, toslink). It can do DSP internally using a C-based language and macros. Expensive and not always available (they make them in small batches).
The HiFiBerry is not a high end solution IMHO.
If you would like a multichannel DAC, I suggest you look at self-powered USB pro audio interfaces such as the Scarlett or Clarett lines from Focusrite, the MOTU M4 (great even without an external PS), and even the Behringer UMC1820 (but not other models from that brand).
The Motu M4 looks like a fantastic bargain. Thanks, Charlie. It could be used for 2-way DSP crossover, correct? Plus mic preamp for measurements!
Edit: scratch that, looks like it isn’t 4 discreet outputs.
However, the Motu 8A checks all the boxes except for the streaming player, for a price.
Edit: scratch that, looks like it isn’t 4 discreet outputs.
However, the Motu 8A checks all the boxes except for the streaming player, for a price.
Last edited:
Under Linux the MOTU M4 has four separate outputs. I think under Windows it might appear as two separate stereo DACs for some reason. There is also a 2 channel version (the M2) that does not have balanced outputs.
For the money, it's a great option. It uses recent generation DAC and ADC that have good performance. See: MOTU M4 Loopback Measurements | Audio Science Review (ASR) Forum
Review here:
Motu M4 Audio Interface Review at Audio Science Review
For the money, it's a great option. It uses recent generation DAC and ADC that have good performance. See: MOTU M4 Loopback Measurements | Audio Science Review (ASR) Forum
Review here:
Motu M4 Audio Interface Review at Audio Science Review
Last edited:
I've a long list of USB DACs to demo, I'm not sure where I'll end up going but off the shelf is likely I think. I'm pretty familiar with SINAD DAC testing and that will help me form my short list.
some of these points are quite interesting and I've thought through some of them already e.g. separate PSUs
It's certainly not a DIY at all cost type answer for me, I want to be sensible, it's about hitting high performance at as low a cost as I can so that I can spend my money elsewhere. Audio quality is key though, so if that means I need to buy a Chord Dave DAC to scratch my itch then so be it.
useful insight, I'm seeing that a PC streamer with built in music storage could be viable, maybe combined with an off the shelf USB DAC though.
Raspberry Pi is interesting, I know a lot of people are using them with upgraded PSUs, if I hadn't have hacked my current streamer case to show that it makes a difference to the sound quality I'd feel a little more open to the idea of using a Pi (in my head bits is just bits....).
I'm currently using a Linn Akurate DS as a streaming source which is the master clock source for the DAC, the case mod I think reduced jitter and gave an improvement.
not sure if a thin client, Pi, or PC for that matter, is going to out perform the Akurate - ideally I want to improve on the Akurate.
I think I'm spoilt for choice for off the shelf DACs, there's lots which measure very well, Topping, chord, Okto, Oppo, mini DSP SHD (interesting option with DIRAC too) etc etc.
think it's a case of looking at features/price then deciding if I have a preference. I'm certainly prepared to invest in the right DAC, it's a key element for me to get right.
I'm not sure if I want/need a multi channel DAC in all honestly, I need to research more about pros/cons coupled with deciding what I'm going to do with my mains and subs and DSP.
--------
1 other thing that I forgot to mention, how does using Jriver/Roon with convolution filter DSP functions compare to a dedicated DSP?
I think the biggest issue is lack of control so in my head they're a non-starter, am I writing them off too soon?
I was looking for some device which is capable of outputting more than the traditional 7.1 channels on PC. I saw the Behringer UMC1820 you mentioned and it have 20 output. Will windows 10 able to manage those 20 outputs, let's say, using software like EAPO?
Hope is posible, but I have doubts about windows 10 being able to manage more than 8 channel.
Hope is posible, but I have doubts about windows 10 being able to manage more than 8 channel.
Honestly, I am not sure what happens under Windows, I only use it under Linux.
NOTE that the UMC1820 has the capability of up to 20 outputs and 18 inputs, but not all of these are "onboard". You only get the maximum number of channels by adding an ADAT interface at 48kHz, like a Behringer ADA8200 with 8 channels each of input and output.
If you expand with an ADAT interface, the sample rate maximum is 48kHz.
NOTE that the UMC1820 has the capability of up to 20 outputs and 18 inputs, but not all of these are "onboard". You only get the maximum number of channels by adding an ADAT interface at 48kHz, like a Behringer ADA8200 with 8 channels each of input and output.
If you expand with an ADAT interface, the sample rate maximum is 48kHz.
I read a lot on Home - Silent PC Review When I build my old PCs. Im not sure the same guy who made the site is still active, but I learned a lot. Today I often play music and movies from my cheap Acer laptop, and have to say I dont notice any noise from it.
Cheers!
Oh. I will also recomend audiosciencereview.com for finding a transparent dac. Seems they dont have to be expensive these days
Cheers!
Oh. I will also recomend audiosciencereview.com for finding a transparent dac. Seems they dont have to be expensive these days
it was useful thanks, no need to apologize
yes I've looked at ASR quite a lot, I think I've pretty much already concluded in my head that buying an off the shelf DAC is the right approach.
think I have options on the streamer as well.
big question then is what to do with DSP.
still unsure if a PC version or off the shelf is best
Here's where I've gotten to, I've done a lot more reading about PC based solutions and I actually think it's going to give me the best answer when coupled with an off the shelf multichannel DAC.
I think my existing main computer running Roon Core, HQplayer (server) with DSD encoding and a DSP program (most likely Acourate for conv filters) will work perfectly, you need a bit of grunt to do the only the fly PCM to DSD encoding, and my main computer has plenty of that. I also really don't want to have to put a silent version of this next to my hifi if I can avoid it.
I'll then connect this PC over ethernet to a small headless NUC (client PC) running the HQplayer client which is outputting over USB to a multichannel DAC.
I just need to figure out if I can build things this way. I'm not 100% sure that the low processing power NUC outputting over USB works, I think it does, but need a bit more research.
I can then make/buy a very high spec silent NUC with good PSU.
I think my existing main computer running Roon Core, HQplayer (server) with DSD encoding and a DSP program (most likely Acourate for conv filters) will work perfectly, you need a bit of grunt to do the only the fly PCM to DSD encoding, and my main computer has plenty of that. I also really don't want to have to put a silent version of this next to my hifi if I can avoid it.
I'll then connect this PC over ethernet to a small headless NUC (client PC) running the HQplayer client which is outputting over USB to a multichannel DAC.
I just need to figure out if I can build things this way. I'm not 100% sure that the low processing power NUC outputting over USB works, I think it does, but need a bit more research.
I can then make/buy a very high spec silent NUC with good PSU.
My set up is Audirvana (everything upsampled to 192K) - Reaper (Equilibrium + time correction plugin used as an active crossover and room correction) - Apogee Symphony DAC. Computer is MacMini sitting upside down on a big heatsink for class A amp. Completely silence even FIR filters are working at 260000 steps. I sometimes use Audirvana Remote on iPad.