Understanding Shielding with a Raspberry Pi in a HIFI Dac. How to Measure noise with (simple tools)
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- čas přidán 5. 07. 2024
- When building a Dac with a RPI how to use earth ground and shields to reduce Noise in your HIFI Music.
Please Note that CPU and Rpi noise is normal any Device with a CPU will have some noise in this Video noise is being amplified a lot so it is detectable, in most cases you will not hear it specially with a good power supply and shielding.
The Rpi is a excellent Audio product when used with good shielding and good Power supplies.
Setup Video for Measuring using a sound card and REW • The Speaker System Aud...
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Amazing video gabster. I have been on a big grounding kick lately. Ran another dedicated ground rod outside of my dedicated music room and ran 2 gauge copper from it into some big 10" 1/2" copper bus bars and I star grounded from there every piece of equipment in my system and it made a really nice improvement.
Thankyou for taking the time to share your findings.
Great demonstration easy to follow and understand Keep up the great work. Love your Videos and this one is no exception. not too many videos about shielding and ground seems a very misunderstood part of the Audio HIFI systems.
Nice Video great to see a visual you make complex problems that few talk about seem easy to understand
Great video - keep pushing whats possible!
Your best video yet! I've watched other videos where they're just "talking heads". This tends to be theoretical and may lack context. Show live examples as you've done takes away all the guess work in understanding and shows actual results. Very excellent!
Thank you glad you liked it 🙏
Good Stuff Gabster nice DIY tips when one can increase the performance PI I will say this (out of band noise) on power above 150k typically won't effect Audio
Excellent demonstration, did you ever experiment with Ferrite sheet to control EMI emission ?
Great! I tested too, just running a wire to a nearby radiator (just for testing first time). My Raspberry was already in a metal housing but still there was a lot of noise. Connected to ground it became as quiet as the room itself. Fantastic. I hear a lot of improvement in the "texture" of music, micro dynamic if you will.
Glad to hear others are experiencing similar results and I am not going crazy :)
@@Gabster1 I am very happy about the improvement in sound quality this made. But now I ask myself is this safe? So I am in an older house and the particular room I use there is no electrical ground, therefore everything runs ungrounded of course. The power amp has an AC ground wire and can(should be?) grounded via AC, however its not and it has run fine for some years. Other equipment has EU AC cable (can be run in both ground and not). Now, all these things hums along quite loud when measured with these fieldreceiver. But as I tried for a starter I just connected a usb-cable to the raspberrypi and connected the shield (the outer metal housing) to a radiator (goes to earth ground) and the hum almost disappears. The sound is great, but as I read about how to ground things I get some cold feet. Is there a better way to do this? It's this mix of ground/notground that worries a little.
This is where making even a small mesh case (faraday cage) with an internal ground point and a grounding lug like I have on my amplifiers and Blu-ray players, would be fantastic.
A solid aluminum case made for whatever your final configuration ends up being with again, an external ground lug, would be fantastic for noise reduction and allow it to be placed next to other components without *potentially, coloring the sound.
I have quite a long RCA cable between my preamp and amp. At first it sounded not really good, it wasn't noisy, but a lot of detail was gone and the imaging was messed up. Then I wrapped the cable with tinfoil and grounded it via an outlet. Night and day difference. The imaging is spot on and the detail is amazing. I have absolutely zero audible noise. It's amazing how you can upgrade your hifi setup by just a few bucks.
I've done this as well... Use a pvc tape layer and then another shield layer, and do it again. I did this three times on my custom xlr cables with pure copper foil and PTFE for thr very best and damn what a difference even with balanced cables... Remember all this balanced noise removal stuff never gets it all so doing more on a very high end system is quite obvw
@@badd99 yeah, I tried this because I am on a tight budget and balanced connection wasn't really an option because neither my preamp, nor my amp support it. And I already had the long RCA cable. It's ugly but it does its job very well.
It’s recommended that you ground all
switching ps! I recommend the iFi groundhog you can use those in conjunction with ipurifier.
Nice, I have a Pi feeding a HAT DAC, so this is very relevant.
The main mod I did was to separate the DAC power from the Pi's power. Now I have the Pi running off a switch-mode DC/DC converter, whilst the DAC is running off a 7805 linear regulator, that made quite an improvement to the sound.
My next mod thought was to move the power/earth feed point from the the micro USB port, to the I/O header side, so the main point of earth & hopefully now the quietest part of the Pi is that that is feeding the DAC.
I like your shield idea, I'll have to source another header block and M2.5 stand-offs to raise the DAC up to make room for the shield.
I'll have to also try your 1KHz tone and analyser setup - REW was it? as seeing the noise rather than just using my ears is real handy.
Hello Gabster, very informative video, thanks ! Some Pi audio-cards (Allo DigiOne ...) have their ground voluntary isolated from Pi's ground. Once they are connected (eg by S/PDIF in Coax) to the DAC itself generally connected to Earth, grounding to Earth the Pi will therefore "short-circuit" the am ground isolation. May this be an issue ? That said I tried myself with and w/o Earth on Pi + DigiOne and for now didn't noticed a significant difference.
Hey Gabi, it's a genius video. Thank you. Do you think that additional grounding of clocks covers like you have ( these small coper covers of Crystek) or case (like Acusilicon clocks) can bring additional benefits?
It would not hurt also provide some thermal shielding and vibration damping
Please show another video looking at shielding with your big dac streamer, effects supercaps have, and maybe even on the clean side of the station pi we shouldn't be stacking the gear.
Also - did you end up sticking with Ian new active i/v board over the transformers?
Some day I hope to try it
I still have the trafo I have no room in that case left to add 2 x 5v power supplies. But will use it in a future design they are both good
Intermodulation distortion surrounding the second and third harmonic reduced drastically with the shielding.
My Sansui is shielded better than most integrated amps can't wait
To review it Gabster it sounds amazing !
'Shielding is huge' with everything in your hifi system' Noise/vibrations are the enemy ! Shielding is the Armor ! Thanks Gabster I use shielding constantly in Industrial Maint '
looking forward to the Sansui Review May the Shield be with you :)
@@Gabster1Wish you lived close by '
If so i would have let you take for a test drive ' for a few weeks '
@@Gabster1 😃 So musical And Creamy sounding with density ' crazy what Conor did with the Sansui its ruined me on $5k and below amps Serously ruined me ! Just wished it had a remote 😆
@@tee-jaythestereo-bargainph2120 Checkout this Arm extension you can use it as a universal remote to any amplifier or device 😄🤪 amzn.to/45sIsBH
Do you use any conditioning on your outlets (iso transformer, Puritan Audio, Furhman , Panamax...)? Can yiu do a video tieing all this together? Tx
Hey Gabby, love your channel. I was wondering if you, haven’t already, discussed using USB to connect a Pi streamer to a DAC. Is the standard Pi4 usb clean enough when powered by a battery, or is there a better USB output that has a USB reclocker? Really appreciate your work! Regards!
I have not done much work with USB not my favorite I prefer a shorter I2s path but you may want to experiment with Allo USBridge but not sure if that is a good way others may know more about a good USB system
A little off topic I suppose but I wonder if shielding an analogue interconnect also takes away from the musical information in the music signal...
The closer and longer the shield to the signal more capacitance starts to occur and on a very sensitive interconnect like say a phono rca you will start to negatively affect the sound
It's all about human balance. The upright stem makes you sit more upright and therefore further back so a benefit going down hill. However, as you mentioned going up hill you're upright position is top heavy further back so the wheel comes off the ground. That's basic physics for you and to most common sense
I found that using Raspberry Zero 2 W is better than using 4b or 3b. Because it has lower power consumption, less heat, and same pinout as the 4b / 3b; Most important, it is "suppose" cheaper. All these are benefitial to hifi diy because of lower noise, lower heat dispense consideration. The only problem is the supply. It's impossible to buy zero 2 W at 15USD.
How do you connect ethernet cable? USB to ethernet adapter?
The one on the left where the ground wire is connected is a power suppy board?
It is just a shielded box to house some protection circuit for the sound card It is described in detail in the video at the end where I talk about the setup in detail
Thank you! What about showing the shield you used? The Altoid lid instead of copper?
They are about the same any metal plate connected to earth ground will be about the same the bigger and more coverage the better I showed it at the beginning but no longer have it gave it to a friend recently. grounding the PI is as important if not more important.
@@Gabster1 thank you!
Hi Gabster, how the measurements are when you use the eaton supercapacitors on the raspberry pi or a battery if you shield or earth?
A new video is not necessary I am only curious if this make sense.
I agree he ideally would have shown the lowest possible he could get it with super caps, grounding the pi, grounding the shield, grounding a second shield
About the same a tad better then PURE Pi but hard to tell as these are approximate very error prone measurements.
I'm also suspecting ground issues with my RPI4 and PurePi/ShieldPi/TransportPiDigi + Ifi IpowerX setup. When I touch the coaxial connector to PiDigi, or PI4 LAN port with a metallic object or with my finger, music interrupts for a second. I also wonder about Pi grounding. Is its ground floating or anything? How could I ground my PI? I don't have a tester. I don't have safety earth enabled in my home electric installation.
Could make a ground by running a wire from any metallic structure that is in the ground that may be ok in a country with no ground it is illegal and not to code to do it in a country with ground socket
I have ground (neutral) in my socket (you can't do without for current) but its schuko safety earth pole is not enabled. Safety earth is for short derivation, not for grounding, isn't it?. I guess external grounding from Pi Lan port to a metallic object at home improves ground that the Pi takes from socket (Ifi DC adaptor plug doesn't have earth pin)?@@Gabster1
IFI is not grounded a metallic object at home would help a lot for a low voltage project like this one it is fine but for high voltage products you take the risk of accidentally electrifying that object @@wyup
How about eddie current created under shields,my streamer sounds better with lid off.
How exactly do you "earth" the RP? Is there a common way to earth any audio PCB (ie a dac or class D amp PCB), even if it runs on batteries? Or, in this case, the negative (- or "ground") serves as "earth" as well, so, no reason to earth at another point? Thanks for this wonderful video.
Just connect a cable to the metal part of one of the Lan ports or usb ports as that is connected to the ground of thr pi.
@@badd99 thank you. How about other battery powered PCB dacs or amps? Can they be earthened too, or ground is the minus of the battery and this is earth too?
They can but be careful Chassis ground is sometimes connected to power ground or Signal ground some equipment may not like that you would need to experiment.
@@Gabster1 Thank you.
@@Gabster1great video. Thank you. Would distancing the HAT with a GPIO ribbon be beneficial? To a separate grounded Mint box.
So could you just attach the plate to the negative end of the/a power supply?
Most power supplies negative is not grounded so it is up to you to ground all your supplies
Some times circuit ground is not power ground
It gets complicated
There are 3 main grounds
Earth ground like in this video
Power ground
And signal ground
Often the first 2 are connected together but not always. Signal ground varies a lot. You can research it online it is a very tricky subject
@@Gabster1 thanks, that helps. I'm building a portable media sharer/power bank/lightbox - I'm looking into extra jack ports because I despise people who inflict their noise on everyone else.
Hi, I think I'll be the voice of the masses here and say that we really appreciate the demonstration, we understand the results and would love to replicate your findings. However, we have no idea how to actually ground the pi.
What do I connect what? Do I need a wire? A special cable? Where do the ends go?
Thank you
Any reasonable size and type of wire will do,
a lot of amps or preamps have a ground terminal on the back. Vintage amps have a phono ground same thing.
Worse scenario but also the best connect a wire from the ground terminal of your AC socket.
Connect it to the metal shield portion of the Pi or Negative power input and also connect it to the additional Shield you created.
hope that helps
@@Gabster1 what is the "metal shield portion of the pi"?
Also, "ground terminal of the ac socket" - any socket, or the one the pi is plugged into? My pi is using a 3 prong plug so how can I connect something to the ground terminal if it has the electrical plug in it? Do I wrap the wire around the middle prong?
Thank you
Hello Gabster! I have an issue with EMC and RPI 5 in my application. Can we get connected via email, to discuss issue that I facing? I hope that you can support me with solution. Can you share any email address that I can contact you ? Best regards, Michal.