Thought I'd share what I've been dabbling with of late.
Still unfinished, but works well.
Essentially a Raspberry Pi with Koalo's I2S driver, fed by an old, badly implemented Kwak clock, feeding I2S to my old PMD100 circuit (resurrected from my previous DAC). This inturn feeds an 8x oversampled I2S signal to a TDA1541A, which feeds a discrete IV stage (a BJT equivalent of Nelson's D1 - very crude at the moment, but works well).
The pi is powered by a dedicated linear PSU, via a USB hub, which also powers a USB (well, SATA) HDD.
It needs a bit of a tidy up, a rebuilt clock and IV stage but I'm very happy with it. No doubt, there are various ways I can tweak this. I'll be busy for years.
Runs MPD nicely, playing FLAC and internet radio, can control it via my phone, and has a shutdown button, so I can run it completely headless.
Seriously toying with an SSD for it - not that it's very noisy at the moment.
Still unfinished, but works well.
Essentially a Raspberry Pi with Koalo's I2S driver, fed by an old, badly implemented Kwak clock, feeding I2S to my old PMD100 circuit (resurrected from my previous DAC). This inturn feeds an 8x oversampled I2S signal to a TDA1541A, which feeds a discrete IV stage (a BJT equivalent of Nelson's D1 - very crude at the moment, but works well).
The pi is powered by a dedicated linear PSU, via a USB hub, which also powers a USB (well, SATA) HDD.
It needs a bit of a tidy up, a rebuilt clock and IV stage but I'm very happy with it. No doubt, there are various ways I can tweak this. I'll be busy for years.
Runs MPD nicely, playing FLAC and internet radio, can control it via my phone, and has a shutdown button, so I can run it completely headless.
Seriously toying with an SSD for it - not that it's very noisy at the moment.
Attachments
Quote :
Still unfinished, but works well.
Essentially a Raspberry Pi with Koalo's I2S driver, fed by an old, badly implemented Kwak clock, feeding I2S to my old PMD100 circuit (resurrected from my previous DAC). This inturn feeds an 8x oversampled I2S signal to a TDA1541A, which feeds a discrete IV stage (a BJT equivalent of Nelson's D1 - very crude at the moment, but works well).
unquote
I am also interested in such a project. I have most of the parts from the diyparadise monica project with TDA 1545.
Can you elaborate more on the PMD 100 circuit ?
I would like to interface the pi with the TDA 1545 chip directly.
thanks
kp93300
Still unfinished, but works well.
Essentially a Raspberry Pi with Koalo's I2S driver, fed by an old, badly implemented Kwak clock, feeding I2S to my old PMD100 circuit (resurrected from my previous DAC). This inturn feeds an 8x oversampled I2S signal to a TDA1541A, which feeds a discrete IV stage (a BJT equivalent of Nelson's D1 - very crude at the moment, but works well).
unquote
I am also interested in such a project. I have most of the parts from the diyparadise monica project with TDA 1545.
Can you elaborate more on the PMD 100 circuit ?
I would like to interface the pi with the TDA 1545 chip directly.
thanks
kp93300
I've tried the TDA1545 (or it might have been TDA1387 which is very similar) and it sounds better run NOS than with oversampling. I compared 2X OS vs NOS and NOS won out with less 'greyness' to the sound. Bear in mind TDA1545A (original TDA1545 isn't available any longer) doesn't use I2S, rather EIAJ.
Thanks for the compliments!
kp, I basically used Guido's circuit for PMD100, but used a set of jumper switches instead of a PIC: DIYHiFi.org • View topic - PMD100 to TDA1541
It's possible, if I could be bothered that I could now use the pi instead of a PIC to program the filter chip using I2C.
(I think there's a diyaudio thread about 7220, where I account my move to PMD100, I think it's easy to find).
I do recall that I did have to modify the driver slightly to get it to work with the PMD100 - I can't quite recall but it was a couple of register pokes to setup an external clock to the pi and to tweak the frame size of the I2S output. I think it's (sort of) detailed in the raspberry pi thread somewhere: Raspberry Pi • View topic - I2S: Anyone got it running? (answer is yes!)
(I do want to update the kernel and rebase my mods, but I'm not in a hurry to do so at the moment).
Abraxilito, 2x NOS is probably not going to make a huge difference. What digital filter did you use? The 4x 7220 was ok, nothing to shout about in my opinion to the 100 for instance. However, you get interesting electrical issues when you start playing with higher frequencies.
When I have access to a scanner, I shall post my IV stage - although it's a work in progress.
I also have more fun with the PSU lined up, an enclosure to sort out and I really want to do something about the clock.... Won't happen overnight though.
kp, I basically used Guido's circuit for PMD100, but used a set of jumper switches instead of a PIC: DIYHiFi.org • View topic - PMD100 to TDA1541
It's possible, if I could be bothered that I could now use the pi instead of a PIC to program the filter chip using I2C.
(I think there's a diyaudio thread about 7220, where I account my move to PMD100, I think it's easy to find).
I do recall that I did have to modify the driver slightly to get it to work with the PMD100 - I can't quite recall but it was a couple of register pokes to setup an external clock to the pi and to tweak the frame size of the I2S output. I think it's (sort of) detailed in the raspberry pi thread somewhere: Raspberry Pi • View topic - I2S: Anyone got it running? (answer is yes!)
(I do want to update the kernel and rebase my mods, but I'm not in a hurry to do so at the moment).
Abraxilito, 2x NOS is probably not going to make a huge difference. What digital filter did you use? The 4x 7220 was ok, nothing to shout about in my opinion to the 100 for instance. However, you get interesting electrical issues when you start playing with higher frequencies.
When I have access to a scanner, I shall post my IV stage - although it's a work in progress.
I also have more fun with the PSU lined up, an enclosure to sort out and I really want to do something about the clock.... Won't happen overnight though.
2X OS was done on an LPC1114 or LPC1313 (can't recall which) with a quasi minimum-phase FIR I designed myself. SAA7220 is a very electrically noisy chip taking as it does about 1W of power - tends to need extra-special care to PSU regulation. In contrast the LPCs (ARM Cortex M0 and M3) take about 40mW or so.
Incidentally how did you feed 8X I2S to the TDA1541A？In my understanding it only accepts data that fast in a mode with two data pins.
Incidentally how did you feed 8X I2S to the TDA1541A？In my understanding it only accepts data that fast in a mode with two data pins.
Did they ever figure out that 44.1k thing?
from
http://www.diyaudio.com/forums/twis...embedded-audio-applicance-20.html#post3837896
also
http://www.diyaudio.com/forums/pc-based/250428-audiophile-optimizer-fish-oil-6.html#post3888449
and
http://www.diyaudio.com/forums/pc-based/250428-audiophile-optimizer-fish-oil-6.html#post3889182
from
http://www.diyaudio.com/forums/twis...embedded-audio-applicance-20.html#post3837896
also
http://www.diyaudio.com/forums/pc-based/250428-audiophile-optimizer-fish-oil-6.html#post3888449
and
http://www.diyaudio.com/forums/pc-based/250428-audiophile-optimizer-fish-oil-6.html#post3889182
Hi.
I also own a RPI. And a friend of mine is also testing this or that I2S DAC on his RPI.
My 2 cents.
The RPI comes with a lot of serious weaknesses and/or limitations. Of course it is working. And people, even beginners, make it work.
The community support is huge and there are a lot of RPI gadgets out there.
However.
I'd recommend to have a look at the CubiTruck instead.
The CT specs are far above an RPI @ just a little extra cost.
It comes with Sata, GBit ethernet, 2GB RAM, case .....
A nice feature is its battery supply option and integrated battery management. No need to fiddle around with linear supplies etc.
There are also I2S headers and there is an I2S driver available.
Another great feature is its NandFlash. No need for SD cards anymore. You put the whole OS on the board.
I'm hard-powering the device up and down several times a day and didn't ever (since January) have any corruptions.
The RPI SD card image corrupted every other day, if the RPI wasn't treated with care.
The SD card slot of the CT can still be used as an alternative boot media.
There are many SD/Nand images for the CT out there. These will get you up 2 speed in shortest time.
So. Don't get stuck forever with the RPI. There's IMO much better stuff out there.
Cheers
I also own a RPI. And a friend of mine is also testing this or that I2S DAC on his RPI.
My 2 cents.
The RPI comes with a lot of serious weaknesses and/or limitations. Of course it is working. And people, even beginners, make it work.
The community support is huge and there are a lot of RPI gadgets out there.
However.
I'd recommend to have a look at the CubiTruck instead.
The CT specs are far above an RPI @ just a little extra cost.
It comes with Sata, GBit ethernet, 2GB RAM, case .....
A nice feature is its battery supply option and integrated battery management. No need to fiddle around with linear supplies etc.
There are also I2S headers and there is an I2S driver available.
Another great feature is its NandFlash. No need for SD cards anymore. You put the whole OS on the board.
I'm hard-powering the device up and down several times a day and didn't ever (since January) have any corruptions.
The RPI SD card image corrupted every other day, if the RPI wasn't treated with care.
The SD card slot of the CT can still be used as an alternative boot media.
There are many SD/Nand images for the CT out there. These will get you up 2 speed in shortest time.
So. Don't get stuck forever with the RPI. There's IMO much better stuff out there.
Cheers
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I tailored my own ArchLinux setup and kernel for the CT. Most of the optimizations applied by the Volumio folks or related community I do know very well. Beside that I'm not going for MPD. MPD has always been performing worse then squeezelite in my setups. Control options of MPD I also consider worse then the "Squeeze" options. Rune and Volumio are doing quite a good job in making MPD more attractive to a wider community though.
Cheers
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No. And there's a reason.
Every I2S DAC board , that's made for working with an ARM board would IMO have be able
1. to slave the ARM board with its own Master clock to achieve best results or
2. it would have to properly reclock and isolate from the transport
If that's not the case I'd rather prefer a well done USB DAC (e.g. ifi Nano DSD).
Let me know if there is any DAC board out there, that would meet those requirements and wouldn't cost more then a 100$ total.
Cheers
That'll break the 100$ limited. I'm no longer willing to spent more (rather less)
then that for digital DIY stuff.
If great commercial products such as the iFi Nano DSD sell at 190$, there is IMO no reason to go for DIY anymore.
Enjoy.
Hi Soundcheck,
(sorry to the OP : off topic here)
Did you give up the powerdac concept ? Great liitle apliance than this little headphone amp+ DAC (happy with the sound ?)... I'd like my smartphone to be able to read a 2.5 USB DD for flac librairy...
Can you please advise me? what would be a good swap to the Squeezebox according to you (but working with squeezebox server) with network to avoid a too big or too powerfull (electricity) pc near the hifi system !
I've got pain to find some-thing but always with wired USB !
Any appliance which allow rj45 to USB to plug a more serious USB to I2S ?
Thank you if any inputs.... The hifi industry but pro one seems to suffer not to know what a local-network is... It lack a SB successor with an USB input + USB output !
(sorry to the OP : off topic here)
Did you give up the powerdac concept ? Great liitle apliance than this little headphone amp+ DAC (happy with the sound ?)... I'd like my smartphone to be able to read a 2.5 USB DD for flac librairy...
Can you please advise me? what would be a good swap to the Squeezebox according to you (but working with squeezebox server) with network to avoid a too big or too powerfull (electricity) pc near the hifi system !
I've got pain to find some-thing but always with wired USB !
Any appliance which allow rj45 to USB to plug a more serious USB to I2S ?
Thank you if any inputs.... The hifi industry but pro one seems to suffer not to know what a local-network is... It lack a SB successor with an USB input + USB output !
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@Eldam.
I've not given up on the FullDigitalAmp. (PowerDac -- sometimes used for DAC+amp in one box - can be misleading). I do try to make things more
simple nowadays. E.g. No seperate SPDIF interface or other boards, no several (DIY-) linear and/or battery supplies and chargers.... Of course
everything needs to be at a rather low budget.
With the iFi device (190$) I'm getting really close. Add to that e.g. a nice Anaview ALC0300-1300 amp (2*mono @300$ ) plus my Cubitruck (110$ incl. PS/Bat). With such a setup I'm more then happy.
I've been testing my LG G2 as USB transport with OTG feeding iFi/Teac/Dragonfly. With USB Audio Player Pro, newest tablets and phones (confirmed also with newest Samsung tablet) you'll get real great transports @ close to no extra cost. IMO No need to toy around with Raspberries, Squeezeboxes or similar anymore - at least when it comes to SQ. Obviusoly you got to own such a device.
However. I replaced my SB Touch with a Cubitruck+squeezelite. I'm outlining that journey on my blog.
Cheers
I've not given up on the FullDigitalAmp. (PowerDac -- sometimes used for DAC+amp in one box - can be misleading). I do try to make things more
simple nowadays. E.g. No seperate SPDIF interface or other boards, no several (DIY-) linear and/or battery supplies and chargers.... Of course
everything needs to be at a rather low budget.
With the iFi device (190$) I'm getting really close. Add to that e.g. a nice Anaview ALC0300-1300 amp (2*mono @300$ ) plus my Cubitruck (110$ incl. PS/Bat). With such a setup I'm more then happy.
I've been testing my LG G2 as USB transport with OTG feeding iFi/Teac/Dragonfly. With USB Audio Player Pro, newest tablets and phones (confirmed also with newest Samsung tablet) you'll get real great transports @ close to no extra cost. IMO No need to toy around with Raspberries, Squeezeboxes or similar anymore - at least when it comes to SQ. Obviusoly you got to own such a device.
However. I replaced my SB Touch with a Cubitruck+squeezelite. I'm outlining that journey on my blog.
Cheers
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