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Bring that "Sweet Tube Sound" to the Raspberry Pi!
Bring that "Sweet Tube Sound" to the Raspberry Pi!
Bring that "Sweet Tube Sound" to the Raspberry Pi!
749 backers pledged $103,748 to help bring this project to life.

PI 3, Pi 2 and noise

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As some of you have found, the Pi 3 emits a small tone that is quite annoying and unacceptable. The Pi 2 does not have this tone, but it has some noise that occurs as the Pi 2 is accessing the SD card and other peripherals. As mentioned before, this is coming into the 503HTA via the 5V rail. While we do have a filter there , it is primarily for high frequency EMI (above 1Mhz), so does nothing for audio band noise.

A proposed solution is to remove (or bend out of the way) the two pins from the Pi GPIO header that is used to feed 5V to the Pi. This would then require the Pi to be powered via it's micro-USB power connector as usual. The good news is that doing this removes the noise completely, including the Pi 3 tone. This tells us also that it was not the WiFi or Bluetooth causing this noise. Note that we did not try to create a lot of traffic via WiFi to see if it causes noise under other circumstances.

The bad news is that you have to modify your Pi, which is something not everyone will be comfortable with. For Pi 2 users, it is probable that you could find the right setting of headphone output resistance that reduces the noise to acceptable levels (as seems to be the case now). For Pi 3 users, it is the only practical way to use the 503HTA with the Pi 3.

Below are a few photos of what we did to the Pi 2 to test (Pi 3 is the same).

bend out pins 2 and 4
bend out pins 2 and 4

 

Top view
Top view

 

503HTA mounted
503HTA mounted

 

Jim Vanderveen, Mike Loebl, and 2 more people like this update.

Comments

    1. Javier Huerta on December 25

      So, you can't use Wi-Fi with the 3 because of the noise, there's a HF roll-off unless you use a script at startup and you can't power the unit with the HAT, again, because of the noise.

      Don't get me wrong, this unit is pretty and it's a great conversation starter. But it surprises me that these issues weren't caught during testing. I mean - this thing uses I2s and it goes to 192/24. It's, quite obviously, geared towards hardcore audiophile / gearheads. Which won't tolerate noise, bent pins, and no wi-fi with their sources.

      Again, thank you very much for your project, and I do love the way my Pi looks, but at this point, I'm just left shaking my head and wondering what on earth should I do with my HAT. It's not a hi-fi unit, it's not a turnkey solution, it's not simple to use, the headphone amp is not even close to spectacular.

      I wish this project had a better happy ending than this. Still, thanks for the effort.

    2. Larry Glenn on December 11

      Yep! I am using a Pi 3 model B, which has built-in wifi, so I disabled it via the Volumio UI and am using ethernet. Between that and bending out the power pins, there's really noise left other than a small one-time burp at startup. Thank you!

    3. Pi 2 Design 2-time creator on December 7

      This is what rwengland wrote in another comment section (not sure why Kickstarter does it that way):

      Clicking Fixed! I suspected (and with your help have now confirmed) that my OurLink WiFi stick was the source of the clicking. The WiFi stick was plugged into one of the four USB Ports on my RPi. I unplugged the stick; plugged in a USB extension cord and then replugged in the USB stick. If the USB stick is moved close to the RPi/503HTA you can hear very audible clicking. Move the USB WiFi stick away from the RPi and voila the clicking is gone. Thanks very much John and Pi 2 Design for the help!

    4. Larry Glenn on December 7

      Same issue as @rwengland here... I've bent the power pins out as suggested, with little improvement. Touching various bits of the assembly will make it better / worse. The noise is not subtle.

      I'm curious -- is there a pi model that doesn't seem to suffer from this problem? The amp is so neat that I'd be willing to get another pi and repurpose the one that I am currently using...

    5. Missing avatar

      rwengland on December 2

      I'm running Volumio and my pi is connected to my network wirelessly via an Ourlink USB stick plugged into a USB port on the Pi. I have a *very* audible clicking noise (~500 to 1khz?) that ceases if I touch the volume pot on the 503HTA -or- the plastic case of the Ourlink USB wifi card. The clicking persists at fixed, audible level at any volume setting. If I increase the volume to annoyingly loud music levels, i can drown out the clicking, but this highly annoying and defeats the purpose of having the 503HTA and Pi dedicated to playing music. Can someone help me address this problem please?

    6. Pi 2 Design 2-time creator on November 28

      I am sorry, I wish we had a better answer. :-(

    7. Missing avatar

      michael on November 26

      I've finally managed to find the time to set this up - but I'm using a Pi3 and the background noise is quite bad. Is there any progress on a fix other than cutting power to the Pi?
      There is a background low static and a high pitched squeal when moving the mouse =(

    8. Pi 2 Design 2-time creator on November 16

      Sorry, the hat only supports model Pi's with the 40-Pin GPI connector.

    9. Javier Huerta on November 16

      I feel pretty dumb for asking this but... the HAT won't fit a Raspberry Pi 1 version B, right? The socket is too big and there's an RCA output blocking the way... ARGH!

    10. Pi 2 Design 2-time creator on November 16

      Also, we needed to order a USB adapter for it.

    11. Pi 2 Design 2-time creator on November 16

      Waiting on a Pi 0. The one we thought we had is no were to be found! Probably lost in the move, or shoved in a box with unrelated stuff.

    12. Javier Huerta on November 15

      Hi, any news on the Pi 0? I'm going to use one with my HAT!

    13. Pi 2 Design 2-time creator on October 27

      Sorry guys, we lost track of testing the Pi 0 and will work on it asap.

    14. Eric B. on October 27

      Sorry Pi1 make more sense...

    15. Eric B. on October 26

      Well, I got the noise a well.... any feedback on the PI0 on that matter? I must confess that having a secong source of power is king of annoying for me...

    16. Missing avatar

      Insik Kim on October 15

      Any updates on the Pi 0 testing?

      Are there any other solutions for Pi 3?

    17. Pi 2 Design 2-time creator on September 27, 2016

      We do not have a B+ here, but we are going to try it on the Pi 0.

    18. Missing avatar

      Chris R on September 27, 2016

      Have you tried it with a B+? I have a couple of these and assume performance may be fine as I use one of these and an original B with hifiberry DACs and Volumio with great results.

    19. Missing avatar

      Mike Loebl on September 26, 2016

      My Pi3 was pretty annoying for the sound. But on the Pi2 it's not a problem at all. TBH once the song has starts playing there's a 1-2s bit of *VERY* subtle nose, however after it starts, even if I pause it, it's dead quiet for me with Volumio. In any case, this looks like a great solution too. Thanks guys!

    20. Pi 2 Design 2-time creator on September 26, 2016

      We are not saying there is a problem. We are saying that the 503HTA, has an unexpected noise when used on some of the Pi 3s (we have two here and one has the noise, while the other has it at a much lower level). On the Pi 2 the noise is very low, but still audible. Some may find this noise objectionable, others may not. So far some have noticed it, but have have not found ti to be too objectionable.

      This thread is for those who want to use the Pi 3 and/or find the Pi 2 noise objectionable. We are offering a possible solution, There may be others as we go along, as Jim Vanderveen has posted about using the stacking connector to isolate the 5V pins.

    21. Missing avatar

      Tony Dyson on September 26, 2016

      Earlier project updates suggested the designers did not find any problems using your new HAT with a Pi 2. Are you now saying this is not the case?

    22. Missing avatar

      Dmytro Protsenko on September 26, 2016

      Is there any chance to deal the problem by modifying the female socket instead of male supply pin, which may be used for other occasions? As i do believe there is a clamp inside of female socket, which may be somehow isolated? Will Amp ever use this two pins in a future?
      I`m sorry for a noob questions.

    23. Pi 2 Design 2-time creator on September 26, 2016

      We agree, and that's why we said it was the bad news. Covering the pins won't work because they are designed to fit very tightly with the female socket and anything on them would prevent it from going in, and thus the whole connector as well.

    24. Missing avatar

      Dmytro Protsenko on September 26, 2016

      As far as i understand the problem is from power source, that causing the noise. I do believe bend supply is slightly harsh decision. I think it is better to somehow isolate the receiving pins.

    25. Missing avatar

      Dmytro Protsenko on September 26, 2016

      Is there any chance just to cover the pins with some isolation tape? Just a small layer or maybe even teflon tape may work?

    26. Pi 2 Design 2-time creator on September 26, 2016

      That's a good idea. The only downside is it makes the standoffs too short. When you get this can you measure the board to board spacing? If it works to a standard size that would be great.

    27. Jim Vanderveen on September 26, 2016

      I will grab a Pi stacking header (eg https://www.adafruit.com/products/1979 ) and just clip off the power leads. It'll add a little height, but won't permanently alter my Pi.

    28. John Bolton on September 26, 2016

      I am quite happy with the situation and since I am an audio engineer for 40 years I am
      sure I would find a solution ! ... Keep up the good work !... John Bolton...