Thanks Ian, for clearing this up and great thanks for the OPA1612 adapter boards. I soldered them using hot air gun on the backside of adapter and with minimum solder paste.
When using SE output, should all the opamps be the same? Currently I have 2x1612 and 1622 on U3. I just don't have more 1612 at hand to do more test.
I just received and installed Ian’s ShieldPi board into my build. I have quite basic un-modded setup with battery supply, FiFoPi, dual ess9038 DAC and opamp output board with OPA1611s installed.
At first I didn’t notice any sonic improvements, but after couple of hours I realized that it was easier for me to tell apart high res files from red book material. So it was a kind of indirect phenomena and I can’t put my finger on what has changed, but anyway in a good direction.
At first I didn’t notice any sonic improvements, but after couple of hours I realized that it was easier for me to tell apart high res files from red book material. So it was a kind of indirect phenomena and I can’t put my finger on what has changed, but anyway in a good direction.
I just received and installed Ian’s ShieldPi board into my build. I have quite basic un-modded setup with battery supply, FiFoPi, dual ess9038 DAC and opamp output board with OPA1611s installed.
At first I didn’t notice any sonic improvements, but after couple of hours I realized that it was easier for me to tell apart high res files from red book material. So it was a kind of indirect phenomena and I can’t put my finger on what has changed, but anyway in a good direction.
Hi Morde,
That's a great news. Thank you so much for your update.
I was getting RF noice when I installed OPA1622 on the I/V STD board if I use Pi3 (with wifi). Other OPAs don't have this problem. Seems that OPA1622 is very sensitive to RF noise. With Shield Pi, it was improved. I'll do more test. New update will be posted once I have.
Good weekend.
Ian
You can, but there will be two issues:
1. You will just use half of DAC chip, either I+ or I-, the performance will be degraded.
2. Common mode noise and possible DC offset can not be rejected.
Ian
Ian to make easy playlist you can also use Cantata,the latest version(2.3.3) is no longer distributed for Windows,you have to take the version the 2.3.2 Release v2.3.2 * CDrummond/cantata * GitHub
the interface is nice to use, the creation of playlists easy to manage.
otherwise there is also Chimney a MPD client Chimney
https://bestwindows8apps.s3.amazonaws.com/cache/3a/5c/3a5c53c783b7d9a7139ed0ff4ec77bed.png
made a try
Ian to make easy playlist you can also use Cantata,the latest version(2.3.3) is no longer distributed for Windows,you have to take the version the 2.3.2 Release v2.3.2 * CDrummond/cantata * GitHub
the interface is nice to use, the creation of playlists easy to manage.
otherwise there is also Chimney a MPD client Chimney
https://bestwindows8apps.s3.amazonaws.com/cache/3a/5c/3a5c53c783b7d9a7139ed0ff4ec77bed.png
made a try
Thank you so much for your help. But I'm running Volumio on RPi. Just want to solve the playlist no play issue. Any idea about that?
I use google chrome with Volumio webUI.
Regards,
Ian
Hi Ian,
did you tried Moode(moodeaudio.org)?
I use it with your dac with better results(to my ears) than volumio.
I never got problem with playlists.
I am using the balanced output without the grond connection, so + and -. This is connected to a volume transformer in my amps and works very good. No problems with ground noise
Moode is the best one I have used (out of volumio, runeaudio, picore player).
There is also a highly recommended sound tweak, you can find it here: GitHub - dynobot/Linux-Audio-Adjustments: Audio Tweaks for Debian Based RPi
My low-noise RPi Audio Best Practices...
Ian, thanks for doing a prototype shield board for this setup. BUT I'm curious if the cure may not be sufficient and may cause additional degradation.
A few weeks back there were some posts (not remembering which thread) on I2S signal degradation for high-rate audio in an Ian GB RPi stack and having to do some signal line tweaking to resolve the issue. I suspect adding another set of connections and signal path length may not improve that situation and likely make it worse.
I know some are experiencing electrical and/or RF interference in certain situations. In my experience, this can easily happen with computer audio... the computers we use for the most part are not designed as audio devices, so by their nature they can easily create more electrical and RF noise than our small RPi-sized DAC and interface boards can handle.
At least with the setups I've used for RPi audio, I have not experienced this. I've been using techniques that served me well and were developed from a few years of playing with motherboard-based I2S-connected DACs. These techniquest transferred well into the RPi world. They are mainly about minimizing sources of electrical and RF noise. I start with the premise that once you have created noise and interference, nothing you do will eliminate it... you can only reduce it. AND that reducing it to where you don't hear any obvious artifacts from the noise and interference does not mean that they are not degrading the SQ you could be getting from your setup.
Here are the best practices that have served me well...
- IF one must use networking (and in most cases you must, if only to control the player), use wired Ethernet. I've taken that a step further by having an optical networking link just before the connection to my RPi... a couple of Fiber Media Converters (FMCs), with the final one being the one that sounded the best to my ears (Delock... which was better than TRENTnet... which was better than TP-LINK). SO I have no electrical connection between my music server and networking gear EXCEPT for that final FMC. With that galvanic isolation in place, I also have my networking gear's AC power coming from a different circuit in my house than the one my audio gear uses, to try and prevent any noise transmitted into the power lines and ground from getting into my audio gear.
- IF one must use WiFI (and I do for control purposes), use an endpoint that is connected via an Ethernet cable and you can put it some distance away from your RPi and audio gear. I have an old DLink router that I've configured as an endpoint and it sits 6'-8' from my RPi and DAC (and the rest of my audio gear). It is connected through a small switch so there is another level of isolation between it and the audio player HW. IF you are using an RPi 3, turn off the on-board WiFi to prevent radiated RFI interference and noise. Also, a question for those more conversant with WiFi HW than I... I chose an older router with the thought it probably had a lower radiated power level than a more modern one. Is this likely true?
- Use linear supplies. There are a number of technical reasons supporting this, but in my experience a linear supply for the RPi and any DAC card and supporting HW (like Ian's FiFoPi or Allo's Isolator and Kali Reclocker) give better results than either low-cost SMPS wall warts or even higher-end SMPSs such as the iFis. Linear supplies don't have to be expensive, large, and heavy... in the US you can get fairly good 5V and 12V 1A linear-regulated wall warts from Jameco for about $20 each. I suspect those in other AC power regions can find similar. They aren't bad as received and I have used them as-is for my networking gear. BUT add low-noise rectifier diodes, more raw DC and post regulator filtering, a snubber, and some basic AC filtering and you have a good basic DAC supply for not a lot of additional cost and not much work (hey, this IS DIYAudio, right?). They use what looks like a low-cost adjustable regulator... I don't remember the model, but I've not been able to find a datasheet. OTOH looking at the V-out setting resistor-divider network, I've been able to take them up or down 2V-3V if different output voltages are needed.
AND for other linear supply options, check the first post in this thread:
Getting the best out of Allo.com's new Katana DAC...
Of course with Ian's GB gear, I strongly suggest his LiFePO4 supply, of course powered by a linear supply (and in the thread for that supply, I've noted a very inexpensive supply on close-out from Jameco that works quite well with it). AND for other setups needing 5V, a great moderate-cost option for audio-quality 5V supplies has been recently released by Allo, their dual 5V (3A and 1A) Shanti supply for about $160USD.
I am ultimately an 'Everything Matters!' type of guy... in my bedroom system (not a typical bedroom system, but actually pretty high-end)... I even use modified Jameco 5V/1A linear regulated wall warts for my bedside phone chargers!
- Minimize processing on the RPi. I use PiCorePlayer as my RPi Distro/player software. The Squeezebox system requires a music server (Logitech Media server or LMS) operating somewhere on a computer that is connected to the RPi via a network connection... or IS the RPi! BUT running the LMS server software on the RPi and connecting an external drive to hold the music files would be the most electrically noisy configuration I believe you could do. To lower local disc and fie processing, I have a separate microcomputer (Zotac Z-Box PI320.. about the size of 2 typical cellphones face-to-face and powered by a single 5V supply... though the Jameco 5V/1A is not sufficient for this application). I chose it as a low-power (think low-noise) solution. Of course I have a small linear supply providing that 5V AND have my music files on an SD Card (512Gb currently) also to minimize electrical noise over what I'd get from a connected USB drive. SO I don't do ANY direct music file access on the RPi, whether from the SD Card or a USB-connected stick or external drive. In the same vein I don't have any other peripherals connected to the RPi... no screen, no rotary controller, just a headless RPi with a power connection, a wired Ethernet connection, and an I2S connection to the audio gear.
Another factor in this is not using HW faster and more powerful than needed. I've stuck to RPI 2Bs as my standard player HW. While it does give me a 'no-WiFi' configuration by design, it is plenty fast and powerful for all of my music needs. It may not be for yours... you have to judge. AND there is currently a school of thought in the motherboard USB-connected audio that the more powerful and fast HW sets give better results. I don't know if that translates to what we are doing here. BUT something to consider and an area for experimentation.
- Experiment with grounding. When I first setup an RPi-based player, I had some significant noise on the output. While I was using linear power supplies for the RPi stack, I had a pair of amps with SMPS's. The solution was to ground the RPi, which I did with a stub USB cable where I clipped a lead I could take to a grounding point. I also generally ground my DAC side (typically they are on the other side of galvanic isolators from the RPi). Of course the first fixed a problem, but later when trying the setup grounded or ungrounded after switching to amps with linear supplies, I still preferred the SQ grounded.
I can't guarantee doing all of the above will eliminate the need for any shielding. For example, Allo uses a shield can over the clocks on their Boss 1.2 and Kantana. I plan to try something similar for the clocks on my FiFoPis. BUT using these techniques and configurations. I have not experienced any electrical or RF noise in my setups for a number of years.
My 2 cents.
Greg in Mississippi
P.S. Another step in minimizing RPi noise (and another reason I stick to the RPi 2B) is that they can be modified using LDOVR.com's RPi Mezzanine board to replace the on-board DC-DC converters with quieter linear regulators. I've done this to 2 RPis and they are my best RPi computer music sources. BUT it is a pretty advanced board to build (if you don't buy it populated from LDOVR.com) and a pretty advanced and tricky mod to the RPi... an admission... I ruined one RPi to get 2 converted. But at $40 or so each, I didn't cry too long once I heard the difference!
P.P.S. IF you use USB connected audio, there ARE some purpose-designed endpoints which are reported to be significant improvements over non-audio-designed endpoints. Of course, that 'high-powered NUC' school of thought I mentioned above is now competing with those devices. In our RPi world, Allo will soon be releasing a USB Bridge Signature, basically a purpose-designed carrier board for an RPi compute module. My understanding is that it should be fairly compatible with our existing Distros / Players and only require the addition of driver for their USB processing subsystem, which was added to resolve the USB-Ethernet resource conflict in the earlier RPis. It of course uses all linear regulators for as low-noise of an environment as possible. I expect it will eclipse my modified RPi 2Bs and become may new player HW standard. I can't wait to get one of my Ian GB FiFoPi -> DAC -> output board stacks on one of these boards!
Ian, thanks for doing a prototype shield board for this setup. BUT I'm curious if the cure may not be sufficient and may cause additional degradation.
A few weeks back there were some posts (not remembering which thread) on I2S signal degradation for high-rate audio in an Ian GB RPi stack and having to do some signal line tweaking to resolve the issue. I suspect adding another set of connections and signal path length may not improve that situation and likely make it worse.
I know some are experiencing electrical and/or RF interference in certain situations. In my experience, this can easily happen with computer audio... the computers we use for the most part are not designed as audio devices, so by their nature they can easily create more electrical and RF noise than our small RPi-sized DAC and interface boards can handle.
At least with the setups I've used for RPi audio, I have not experienced this. I've been using techniques that served me well and were developed from a few years of playing with motherboard-based I2S-connected DACs. These techniquest transferred well into the RPi world. They are mainly about minimizing sources of electrical and RF noise. I start with the premise that once you have created noise and interference, nothing you do will eliminate it... you can only reduce it. AND that reducing it to where you don't hear any obvious artifacts from the noise and interference does not mean that they are not degrading the SQ you could be getting from your setup.
Here are the best practices that have served me well...
- IF one must use networking (and in most cases you must, if only to control the player), use wired Ethernet. I've taken that a step further by having an optical networking link just before the connection to my RPi... a couple of Fiber Media Converters (FMCs), with the final one being the one that sounded the best to my ears (Delock... which was better than TRENTnet... which was better than TP-LINK). SO I have no electrical connection between my music server and networking gear EXCEPT for that final FMC. With that galvanic isolation in place, I also have my networking gear's AC power coming from a different circuit in my house than the one my audio gear uses, to try and prevent any noise transmitted into the power lines and ground from getting into my audio gear.
- IF one must use WiFI (and I do for control purposes), use an endpoint that is connected via an Ethernet cable and you can put it some distance away from your RPi and audio gear. I have an old DLink router that I've configured as an endpoint and it sits 6'-8' from my RPi and DAC (and the rest of my audio gear). It is connected through a small switch so there is another level of isolation between it and the audio player HW. IF you are using an RPi 3, turn off the on-board WiFi to prevent radiated RFI interference and noise. Also, a question for those more conversant with WiFi HW than I... I chose an older router with the thought it probably had a lower radiated power level than a more modern one. Is this likely true?
- Use linear supplies. There are a number of technical reasons supporting this, but in my experience a linear supply for the RPi and any DAC card and supporting HW (like Ian's FiFoPi or Allo's Isolator and Kali Reclocker) give better results than either low-cost SMPS wall warts or even higher-end SMPSs such as the iFis. Linear supplies don't have to be expensive, large, and heavy... in the US you can get fairly good 5V and 12V 1A linear-regulated wall warts from Jameco for about $20 each. I suspect those in other AC power regions can find similar. They aren't bad as received and I have used them as-is for my networking gear. BUT add low-noise rectifier diodes, more raw DC and post regulator filtering, a snubber, and some basic AC filtering and you have a good basic DAC supply for not a lot of additional cost and not much work (hey, this IS DIYAudio, right?). They use what looks like a low-cost adjustable regulator... I don't remember the model, but I've not been able to find a datasheet. OTOH looking at the V-out setting resistor-divider network, I've been able to take them up or down 2V-3V if different output voltages are needed.
AND for other linear supply options, check the first post in this thread:
Getting the best out of Allo.com's new Katana DAC...
Of course with Ian's GB gear, I strongly suggest his LiFePO4 supply, of course powered by a linear supply (and in the thread for that supply, I've noted a very inexpensive supply on close-out from Jameco that works quite well with it). AND for other setups needing 5V, a great moderate-cost option for audio-quality 5V supplies has been recently released by Allo, their dual 5V (3A and 1A) Shanti supply for about $160USD.
I am ultimately an 'Everything Matters!' type of guy... in my bedroom system (not a typical bedroom system, but actually pretty high-end)... I even use modified Jameco 5V/1A linear regulated wall warts for my bedside phone chargers!
- Minimize processing on the RPi. I use PiCorePlayer as my RPi Distro/player software. The Squeezebox system requires a music server (Logitech Media server or LMS) operating somewhere on a computer that is connected to the RPi via a network connection... or IS the RPi! BUT running the LMS server software on the RPi and connecting an external drive to hold the music files would be the most electrically noisy configuration I believe you could do. To lower local disc and fie processing, I have a separate microcomputer (Zotac Z-Box PI320.. about the size of 2 typical cellphones face-to-face and powered by a single 5V supply... though the Jameco 5V/1A is not sufficient for this application). I chose it as a low-power (think low-noise) solution. Of course I have a small linear supply providing that 5V AND have my music files on an SD Card (512Gb currently) also to minimize electrical noise over what I'd get from a connected USB drive. SO I don't do ANY direct music file access on the RPi, whether from the SD Card or a USB-connected stick or external drive. In the same vein I don't have any other peripherals connected to the RPi... no screen, no rotary controller, just a headless RPi with a power connection, a wired Ethernet connection, and an I2S connection to the audio gear.
Another factor in this is not using HW faster and more powerful than needed. I've stuck to RPI 2Bs as my standard player HW. While it does give me a 'no-WiFi' configuration by design, it is plenty fast and powerful for all of my music needs. It may not be for yours... you have to judge. AND there is currently a school of thought in the motherboard USB-connected audio that the more powerful and fast HW sets give better results. I don't know if that translates to what we are doing here. BUT something to consider and an area for experimentation.
- Experiment with grounding. When I first setup an RPi-based player, I had some significant noise on the output. While I was using linear power supplies for the RPi stack, I had a pair of amps with SMPS's. The solution was to ground the RPi, which I did with a stub USB cable where I clipped a lead I could take to a grounding point. I also generally ground my DAC side (typically they are on the other side of galvanic isolators from the RPi). Of course the first fixed a problem, but later when trying the setup grounded or ungrounded after switching to amps with linear supplies, I still preferred the SQ grounded.
I can't guarantee doing all of the above will eliminate the need for any shielding. For example, Allo uses a shield can over the clocks on their Boss 1.2 and Kantana. I plan to try something similar for the clocks on my FiFoPis. BUT using these techniques and configurations. I have not experienced any electrical or RF noise in my setups for a number of years.
My 2 cents.
Greg in Mississippi
P.S. Another step in minimizing RPi noise (and another reason I stick to the RPi 2B) is that they can be modified using LDOVR.com's RPi Mezzanine board to replace the on-board DC-DC converters with quieter linear regulators. I've done this to 2 RPis and they are my best RPi computer music sources. BUT it is a pretty advanced board to build (if you don't buy it populated from LDOVR.com) and a pretty advanced and tricky mod to the RPi... an admission... I ruined one RPi to get 2 converted. But at $40 or so each, I didn't cry too long once I heard the difference!
P.P.S. IF you use USB connected audio, there ARE some purpose-designed endpoints which are reported to be significant improvements over non-audio-designed endpoints. Of course, that 'high-powered NUC' school of thought I mentioned above is now competing with those devices. In our RPi world, Allo will soon be releasing a USB Bridge Signature, basically a purpose-designed carrier board for an RPi compute module. My understanding is that it should be fairly compatible with our existing Distros / Players and only require the addition of driver for their USB processing subsystem, which was added to resolve the USB-Ethernet resource conflict in the earlier RPis. It of course uses all linear regulators for as low-noise of an environment as possible. I expect it will eclipse my modified RPi 2Bs and become may new player HW standard. I can't wait to get one of my Ian GB FiFoPi -> DAC -> output board stacks on one of these boards!
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