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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.

Quick Start Guide - sort of...


I know you guys are happy we've started shipping, but also wondering where the documentation is. Some of you are smarter than the average bear (a Yogi Bear Cartoon reference for non-US folks) and have gotten things going despite our terrible lack of help. For now we are posting a set of 3D renders that shows the main connectors and switches. Also some simple notes about using. So here goes.

Major component locations
Major component locations

1. The 503HTA is designed to connect to any Pi with a 40-pin GPIO. Simple line up the holes and the connector and gently press in.

2. When you fire up your Pi and run your chosen player (that we can not help with as there are many to choose from) simply select the Hifiberry DAC (not DAC+) as your audio device/card.

3. For tube rollers there are the two pots and a small 3-pin header labeled R-G-L, for Right-Ground-Left. Be VERY careful not to short either L or R to G! It will destroy the bias transistor and will require a repair trip back to us. We suggest using some female to male jumper wires such as these from Adafruit:

Of course, you must also be aware of the 6V/12V jumper and make sure it in the right location.

4. At the factory we adjust the voltage at R and L to 13.4V. This places the output center with enough margin for up to ~14V P-P or 5Vrms. Biasing lower (12V for example) will give more margin, but, at least with the 6922/6DJ8, the distortion is the best when the bias is higher. For low ohm headphones that are reasonably efficient (90db+) you could go as high as 16V. As always, your experience may vary and is highly dependent upon the headphones used.

5. The 3-position slide switch selects between 0, 47 and 100 ohm output resistance. IF you are using low ohm headphones (32-50) you should select the 100 (right most) position. This reduces the load on the amp and provides the lowest noise operation on the Pi.

6. The toggle switch next to the volume pot selects 0db (down) or 10db (up) attenuation. This applies to both the Pi DAC output and the Line In signal.

7. When you insert a 3.5mm jack into the Line In connector, the amp automatically switches to that signal. This input is rated for up to 2Vrms (same as the DAC).

8. If you want to drive a downstream amplifier, you should select the 10db attenuation. With the DAC at full output and the volume pot all the way to the right you will get ~2Vrms out. Be careful as you can easily over-drive (and possible damage) downstream equipment if you drive to high.

One more note, as mentioned in the campaign and pledge descriptions, we do NOT supply a power cord. We had a previous campaign and it turned out to be a real problem getting the right cords (UK especially) here in the US. If we could have used a smaller supply we might have gone with a wall wart type with interchangeable plates. But the 24V 2A supply is bit higher power (55W total) to be put into a wall wart. We're sorry if this was not noticed by you and made you scramble around to find a cord. Please accept our apologies.

Mike Loebl, Javier Kadry, and 7 more people like this update.


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    1. Missing avatar

      Scott Drennan on November 2, 2016

      Nicolas/Joseph, I was able to get mine working following the Hifiberry-DAC instructions here:

      I'm running Raspbian 8 (jessie), and needed to change two things: /boot/config.txt and /etc/asound.conf, both following the Hifiberry instructions. (There's a ~pi/.asoundrc file which isn't mentioned in the Hifiberry instructions - I left it alone since it's identical to /etc/asound.conf)

      From that, after installing mplayer (again following the Hifiberry instructions) I was able to successfully play back a FLAC file).

    2. Missing avatar

      nicolas caillier on November 1, 2016

      A couple of clarifications would be welcome.
      I used the latest raspbian image and use VLC, but there is no new soundcard detected by the system. What options should i change ?
      Also about the 6V and 12v option, is related to the headphone you use ? or to the power supply 110/220V ?

    3. Missing avatar

      Joseph Kelley on October 18, 2016

      Is there ANY Raspbian software documentation? I can't get my HAT to work on my RPi 2 or my RPi 3. I'm sure there's some module I need to load or something I need to change in config.txt, but I can't get Raspbian or VLC to recognize the HAT. Anyone else having this problem? Right now I just have a glowing paperweight!

    4. Pi 2 Design 3-time creator on October 6, 2016

      We should carry this conversation directly. Not that we're hiding anything! Too much info is more our style! But, it would be quicker and easier. Send your email to It's his job to take it on the chin since it's his design.

    5. Missing avatar

      Sean on October 6, 2016

      Sure. Thanks.

      I believe the problem is with the the hat itself. I tested the supplied power supply with my multi-meter and it has 24v in the barrel plug. There is a small red LED on the hat under the tube that seems to flicker on and off, sort of like there may be a bad solder or loose connection. Pictures in a moment.

    6. Pi 2 Design 3-time creator on October 6, 2016

      Can you send some photos of your setup to We can better support you if we can get a sense of how the unit is installed on the Pi and the power cable, etc.

    7. Missing avatar

      Sean on October 5, 2016

      OK, I'm lost. I can't even tell if the damned thing is on or not. Yes, it is plugged in.

      I'm only a partial noob. I have assembled the hat onto a RasPi 3. I have bent the 5V pins as per the post on noise. I have loaded up RuneAudio and booted the board. I have been able to SSH into RuneAudio and tweak the necessary config files so the Hifiberry DAC shows up in the RuneAudio web page. I have media available to play, only nothing is coming out of the headphones I have plugged in. The volume control doesn't seem to have an impact. I suspect there is no power going through the amp because the heatsink is cold to the touch.

      Any suggestions? I am more than a bit frustrated at this point.

    8. Pi 2 Design 3-time creator on October 4, 2016

      There is no SW detection method for the PCM5102A DAC we use. You just tell the player you are using the Hifiberry DAC (not DAC+) and it will load the right drivers.

    9. Patrick James Bell II on October 3, 2016

      Anyone else have any problem getting the dac to be seen. I'm not getting it to show. The patch up from the pi by jumper cable works but I would like to see the fav in action