Interfacing Raspberry Pi and TPA3116D2 amp

[xrk971]

Thanks.

Unfortunately I did not take photos from the inside and already took it apart, cause that was only a fun project and I needed the Raspberry for my main system.

The others liked it a lot. If you are interested in more photos, have a look here

Frickelfest 2014/hb

and here

Frickelfest 2014

The turntable is an old Braun PC-3 that I totally rebuilt and modify together with a 7" unipivot tonearm that I constructed and built myself:

Sorry for the o.t.

No worries for OT. It's very interesting to see analog hear side by side with all digital Rasp pi and class D amp. I will have to build myself a custom turn table from scratch one of these days. I guess I will need a phono preamp though before going into 3116 or Rasp pi. Very nice work on that turntable - like the simplicity.

 

[Downunder55]

How to resolve an annoying noise ?

The project is powered by a 19V 4.5A laptop power supply, this powers the Audiobah amp @ 19v and also powers a little board that drops the 19v to 5v to power the Raspberry Pi with HiFiBerry and Router.

The little black box is a small NAS wireless router to connect the 2.5" SATA drive with the FLAC music library, it has a network link to the Pi and to also provides the wireless network for the iPad to drive the sensational Rune UI. RuneAudio - Embedded Hi-Fi music player

All is working beautifully but with just one little annoying issue that is a small scratching sound and some indistinct noise with no music playing, that doesn't really increase with increased volume. The scratching sound changes markedly with Pi activity !

So far have identified after much testing:

1. The AMP with no connections is silent.

2. If the Pi only is powered from another power source the noise goes away

3. If the Pi line output is disconnected the sound goes away

4. If I connect a chassis mounting hole on the Amp to the metal surround of the RCA connectors (Ground) on the Pi (yellow, red or white) the noise is eliminated.

I have changed both the cables from the Pi to the Pot and the Pot to the Amp

I have resoldered the joints on the HiFiBerry, at the Pot and on the Amp to eliminate any dry solder joints.

I have tried a different brand Pot and mounting board

I have checked with a multimeter (set on the 200 resistance setting) the connection cables ground wire from end to end through the Pot and get the same reading (0.6) as when I just connect both probes.

This has me thinking I do have a grounding issue ? ....... but I don't seem to be able to eliminate it, what else can I try any help appreciated ?

 

[xrk971]

The project is powered by a 19V 4.5A laptop power supply, this powers the Audiobah amp @ 19v and also powers a little board that drops the 19v to 5v to power the Raspberry Pi with HiFiBerry and Router.

The little black box is a small NAS wireless router to connect the 2.5" SATA drive with the FLAC music library, it has a network link to the Pi and to also provides the wireless network for the iPad to drive the sensational Rune UI. RuneAudio - Embedded Hi-Fi music player

All is working beautifully but with just one little annoying issue that is a small scratching sound and some indistinct noise with no music playing, that doesn't really increase with increased volume. The scratching sound changes markedly with Pi activity !

So far have identified after much testing:

1. The AMP with no connections is silent.

2. If the Pi only is powered from another power source the noise goes away

3. If the Pi line output is disconnected the sound goes away

4. If I connect a chassis mounting hole on the Amp to the metal surround of the RCA connectors (Ground) on the Pi (yellow, red or white) the noise is eliminated.

I have changed both the cables from the Pi to the Pot and the Pot to the Amp

I have resoldered the joints on the HiFiBerry, at the Pot and on the Amp to eliminate any dry solder joints.

I have tried a different brand Pot and mounting board

I have checked with a multimeter (set on the 200 resistance setting) the connection cables ground wire from end to end through the Pot and get the same reading (0.6) as when I just connect both probes.

This has me thinking I do have a grounding issue ? ....... but I don't seem to be able to eliminate it, what else can I try any help appreciated ?

I think you are picking up noise from the wifi activity. I hear the same thing when the radio frequency activity light on my 802.11g USB wireless dongle blinks. Try turning if wifi and see if problem goes away. Hard to fix this one as that rf is very powerful and pervasive. You can try using shielded input wires and use a separate power source between the amp and the rasp pi.

 

[camelator]

Fair comment, I only use FLACs ripped from CD so not stressing it with higher res.

I think the advantages of the Pi are-
1. Strong support - plenty of audio SW and HW for the Pi
2. Supports I2S thus able to build a very cost effective player from a Pi and a cheap I2S DAC (long as it doesn't need a MCK) although the I2S implementation is not the best.

Otherwise I would go for a better performing platform - BBB, Wandboard, Cubietruck... But as things stand there are few prebuilt audio image/player SW packages available for these other platforms so be prepared to get your hands dirty with the SW.

Well, I have raspberry and cubie board.
What I can say, is because of lack of support for cubie board and cubie truck, raspberry with I2S is much better than cubie board.

OS updates are more frequent.
I2S advantages.

Raspberry -- : I can say raspberry pi is slower for sound control than the others. But I prefer sound quality vs sound control (volume, tracks,...)

My DAC is a hifiberry, and just tried another one. To be honest, I can not listen huge difference.

Wolson could be interesting with FIR filters, as you can plug a microphone and easily use REW to adjust your curves (well I think)

 

[den_hr]

2. If the Pi only is powered from another power source the noise goes away

3. If the Pi line output is disconnected the sound goes away

4. If I connect a chassis mounting hole on the Amp to the metal surround of the RCA connectors (Ground) on the Pi (yellow, red or white) the noise is eliminated.

Well, from the above I'd say you have an issue with the DC-DC converter that feeds the RasPi, which might be introducing some ground noise (???)

But, if under 4) above you say the noise is eliminated, then I see no problem: just connect the grounds, and that's it... problem solved... Another thin wire shouldn't matter much.

BTW, did you try changing the laptop "brick" for another? Is the one you are using grounded (i.e. does it have a grounded power plug that plugs into grounded power socket on the wall)?

In the attached photo you can see how I'm powering everything: the TPA3116 amp (on the right) is powered separately by 12v/4A brick, and the RPi is powered through a white powered hub in the middle of photo (5v/2A). The hard disk (black WD to the left of the amp) has its own power supply (wall wart). The mini wifi adapter is plugged directly into RasPi.
No hum or any other issues. However, this means I'm powering each device separately (3 separate power supplies)

Once I get everything into the same enclosure, I expect I might run into similar problems, since the idea is to use a single power supply that provides 12V and 5V.
I think a good start would be to use a grounded power supply, and start from there.

 

[skood]

I'm using Raspberry Pi + I2S Geekroo dac and TPA3116D2 amp - sounds great to me using 24v
Using Volumio to interface -

- I also tried my usb Monica 3 dac which also sounded very good.

 

[den_hr]

I'm using Raspberry Pi + I2S Geekroo dac and TPA3116D2 amp - sounds great to me using 24v
Using Volumio to interface -

- I also tried my usb Monica 3 dac which also sounded very good.

Any additional info on these DACs?

I'm looking for a good I2S DAC that could be used also with other RasPi models (e.g. new RasPi B+)...

I see that gekroo DAC does 32/384... How is the sound?

TIA,

Denis

 

[skood]

I'm not really technical but the sound is pretty good, no complaints for $40 ; sounds as good as the Monica i think.

i don't think you would be disappointed..

 

[surfstu]

Well, this post may have changed my plans to marry a cheap Chinese 3116 circuit board here with a raspberry Pi and hifiberry - powering everything from one laptop brick.

Anyone with any thoughts on the 3116 module in question? And - more importantly on the PSU?

Anyone else with experience of tapping off a 5V supply for a raspberry Pi from a laptop supply?

stu

 

[den_hr]

Anyone with any thoughts on the 3116 module in question? And - more importantly on the PSU?

Anyone else with experience of tapping off a 5V supply for a raspberry Pi from a laptop supply?

stu

I'm collecting the "bricks" just for that purpose: powering both the RasPi and the TPA3116 with the same "brick".

I'll be trying the "bricks" used to power external HD enclosures - they usually have dual power 5V and 12V, although usually only 2A per branch (i.e. 5v/2A and 12v/2A) - I'm not sure if 12v/2A will be enough for TPA3116. I have a couple, so I'll try one soon... So many ideas to try out, and not enough time

 

[Downunder55]

Anyone with any thoughts on the 3116 module in question? And - more importantly on the PSU?

Anyone else with experience of tapping off a 5V supply for a raspberry Pi from a laptop supply?stu

Plenty of thoughts and alternatives in this thread http://www.diyaudio.com/forums/class-d/237086-tpa3116d2-amp.html

I used this to drop a spare 19v laptop PS to 5v, available for a few $'s on eBay, I still have a small grounding problem, but really don't think it is this unit causing it.

 

[zog666]

Plenty of thoughts and alternatives in this thread http://www.diyaudio.com/forums/class-d/237086-tpa3116d2-amp.html

I used this to drop a spare 19v laptop PS to 5v, available for a few $'s on eBay, I still have a small grounding problem, but really don't think it is this unit causing it.

I have been using a similar DC-5VUSB converter (low cost ebay unit) for several years in my TK2050/Raspberry Pi music player and it has been excellent, the whole setup runs very quiet. I'd actually have to say one of the best 5V USB power supplies I have tested (and I have tested quite a few) - using one of those "USB doctor" voltage/current checkers to verify it's voltage output.

 

[xrk971]

If you have ground loops try a Murata isolated DC-DC converter. They will take 19v or 12v depending on model and drop to 5v with an isolated ground. Cost about $5ea but sometimes is the only way to get rid of ground loop noise.

 

[den_hr]

I'm not really technical but the sound is pretty good, no complaints for $40 ; sounds as good as the Monica i think.

i don't think you would be disappointed..

Well, I just bought one Gekroo PiCobber DAC - we'll see when it arrives

I like it that it already has GPIO IR sensor - one less worry, and one USB port less. We'll see how I'll be able to interface an I2C character LCD - it was a minor problem with the Wolfson audio card: I had to do some careful soldering....

 

[webby]

Hi All,
I soldered in a IQaudIO.com Pi-DAC with a Audiophile TI Burr Brown 32-bit/384kHz DAC (TI PCM5122) to my RPI, very easy! They make a neat case for the pair.They have just released a B+ version that requires no soldering.
I run Rune as a OS/server, controlled by Ipad or Android.

The sound quality is excellent, right up there with my vinyl setup.
Many thanks
Ian