My RPi + Allo Boss DAC + TPA3116D2 Amp

[saheb11123]

Think of it this way - done right, it's probably 99% of the sound at 99% [not really, but close] cost savings.

I'd reconsider the percentage

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[SanjeevM]

Great work Sanjeev!

I am also using a Raspberry Pi 3 with Allo Boss DAC for casual listening in the dining area with Adam A5X active speakers. I was impressed with what this cheap DAC could do. It produces very smooth and warm sound. I also compared it with DragonFly and Chord Mojo.

I chose to use an iPad (or any mobile phone on the table) to control Volumio, instead of a separate touch screen display near the system. Anyway that is just a personal usage preference, with no impact on the sound. It is exciting to see how technology is evolving now. The end users like you and me have so much control over how we create and upgrade stuff based on our individual choices. I am glad that local companies like Allo are producing great world class products.

Regards,
Sharad Medhavi

Hi Sharad,

I have used the touchscreen for three reasons: I wanted to try one, cosmetic, and a fallback option when the network is down. Otherwise normally I run the player thru my Tab or Android phone. The touchscreen is not necessary in the system, otherwise.

I am amazed at the quality of sound which the player puts out, at a fraction of the cost and complexity of the Class-A amplifier.

Regards,
Sanjeev

 

[samyoo]

Thanks sanjeevji, very very impressive, please guide me,I want to build this kind of amp, but I have zero technical knowledge, if you described with a tutorial video, total cost and where I can buy ! Thanks once again for your superior idea !

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[SanjeevM]

Actually, very little knowledge is needed to assemble this player.

You need:
1. Raspberry Pi 3,
2. Allo Boss Dac
3. Power adapter for RPi,
4. WiFi dongle
5. TPA3116D2 chip based amp board,
6. SMPS 24V 5A for the Amp board
7. SD card 16GB Class 10 with card reader
8. Pen drive for songs
9. Optionally, the 7inch touchscreen.

Sources you can use

For 1,2,3,4 &9 - diyaudiocart.com or crazypi.com

For 5 & 6 - eBay.com

For assembling you need the simplest of tools.

You need to download the latest Volumio player image for www.volumio.org and write it on the SD Card.

Also, download the volumio player app from the play store. Its helpful.

You should have a wifi router at home, or you can take a small piece of Lan cable.


Best of luck !!

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If you face problems in assembly, there are many learned FMs who will help.

For the cabinet, I used MDF board 6mm thk base & 4mm sides, which I got lader-cut, drilled & assembled from a carpentry shop.


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@JLS,

I have noticed that this player plays Flac files really well. The o/p is very very sweet and musical, with awesome detail. In Wav files, the o/p is clinically good.

The Arcam does better on WAV files.

Perhaps there is a difference in the way decoders have been written on the two systems !!


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[saheb11123]

@JLS,

I have noticed that this player plays Flac files really well. The o/p is very very sweet and musical, with awesome detail. In Wav files, the o/p is clinically good.

The Arcam does better on WAV files.

Perhaps there is a difference in the way decoders have been written on the two systems !!


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Which arcam dac have you got and what is the dac chip?

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[samyoo]

Thanks let me try ! What would be the power? Means watts, ohms etc

 

[SanjeevM]

Thanks let me try ! What would be the power? Means watts, ohms etc

Power is 50W per channel into 4 ohms.

 

[samyoo]

Power is 50W per channel into 4 ohms.

can I increase the watts and ohms?

 

[SanjeevM]

Which arcam dac have you got and what is the dac chip?

I am using an Arcam iRDAC, which has the Burr Brown 1796 DAC chip.

can I increase the watts and ohms?

No, I'm afraid. That's the max output. If you use 4 ohm speakers, the output power is 50W per channel.

My speakers are 8 ohms; the sound is not earth shattering or lease busting, but I can't listen to full volume for long. There are tracks which have been recorded at low volume, the sound level is just OK for those.

 

[SanjeevM]

Dear FMs,

I want to see if there is a significant improvement in the quality of sound of the 3116D2 (chiefly, does it make the vocals and highs smoother, and improves the bass punch) when run on a Linear Power supply.

Present Setup:
Allo Boss DAC : runs on the supplied power adapter 5V 3A (must be smps)
3116D2 : runs on a 24V 5A SMPS PSU (China made)

Proposed setup:
Allo Boss DAC : Linear Trafo PSU 5V 5A with 1 Farad Supercapacitor to kill ripple
3116D2 : Linear Trafo PSU 24V 8A, no regulator, with 20,000 uF capacitor bank. I dont want to do a CRC filtering right now, but if required, I will modify the circuit. (The main Trafo will have a separate 5V winding for the 5V o/p to DAC)

Can you suggest any improvements please.

I tried using a buck circuit to power the RPi, by taking the output from the 24V 5A SMPS which is powering the class-d 3116, and lowering it to 5V by the buck circuit.

The result was a hiss and a disappointing fall in SQ from the RPi+Boss. Restored the RPi adapter supply, and got back the SQ.
Obviously, the DAC is sensitive to the hi freq noise that the buck generates.

Wondering whether to buy a Capacitance multiplier, or a linear supply for the 3116D2 .....

 

[kane]

I tried using a buck circuit to power the RPi, by taking the output from the 24V 5A SMPS which is powering the class-d 3116, and lowering it to 5V by the buck circuit.

The result was a hiss and a disappointing fall in SQ from the RPi+Boss. Restored the RPi adapter supply, and got back the SQ.
Obviously, the DAC is sensitive to the hi freq noise that the buck generates.

Wondering whether to buy a Capacitance multiplier, or a linear supply for the 3116D2 .....

Hey Sanjeev, the CP details.

"This circuit is very suitable for class A and class D amplifiers or even to feed clean power to your SBCs.
Our CM board supports from 10V to 32V input @ 5 Amps."


I have powered the raspberry via the Kali ( through the Allo power supply for Sparky ) as well as the dual Power supply by allo and the difference is NOT heaven and earth, the Dual power supply does seem cleaner and they are subtle hints in the music when you hear it ..

The RPI 3 and boss dac however when i used the Official rpi power supply as well as the DUal PSU by allu there was a big difference. in the sound. so yes a clean power supply does help.


But when you power the SBC via kali, Kali does a good bit of filtering to the electrical input i guess, and that why the difference is not as obvious i guess.

Allo has a new product called Isolator and i think that will help a bit as well. i am going to order it in the next week and will test and see how that goes.

 

[Tmr_suresh]

Dear Members,
i am also planning to build rasberry pi dac for my audio system. all i need is rasberry pi connected to dac and usb hdd for songs. control is through the lcd display . may be using mobile also . but i don't want it to be connected to internet. is there a way to do it? a stand alone player .

Regards,
R.Suresh.

 

[kane]

Dear Members,
i am also planning to build rasberry pi dac for my audio system. all i need is rasberry pi connected to dac and usb hdd for songs. control is through the lcd display . may be using mobile also . but i don't want it to be connected to internet. is there a way to do it? a stand alone player .

Regards,
R.Suresh.

get Volumio create a bootable sd card with it and run it on the raspberry pi. Volumio also run in hotspot mode and will create a wifi hotspot, which you can connect your mobile to, this way the raspberry will not be connected to the internet but will still allow it to be controlled by a mobile.

 

[SanjeevM]

get Volumio create a bootable sd card with it and run it on the raspberry pi. Volumio also run in hotspot mode and will create a wifi hotspot, which you can connect your mobile to, this way the raspberry will not be connected to the internet but will still allow it to be controlled by a mobile.

To add to Kane's post:

If you configure a hotspot but not the wired and wireless network, volumio automatically enables the hotspot. Then you can connect to the hotspot by typing the IP address. Since there is no other network, your player is not connected to the internet.

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[Aniket]

Hi,

Why in this world, one would use a tpa class d amp for hi-fi music listening, i believe its a serious project here but ruined by a crappy chip, which is made to be used in sound docks, soundbars and boom boxes powered through a battery or a cheap Chinese adapter. i have seen these chips even in jbl soundbars also, which after some months either fry themselves or the speakers.

 

[Tmr_suresh]

get Volumio create a bootable sd card with it and run it on the raspberry pi. Volumio also run in hotspot mode and will create a wifi hotspot, which you can connect your mobile to, this way the raspberry will not be connected to the internet but will still allow it to be controlled by a mobile.

Thank you . will let you know when every thing is ready .

 

[Kannan]

any link to a cheapo wifi adapter that works out the box with Volumio

 

[jls001]

Why in this world, one would use a tpa class d amp for hi-fi music listening, i believe its a serious project here but ruined by a crappy chip, ...

I wouldn't, by any stretch of imagination, call TPA3116/3118 crappy chips when implemented correctly and used in the linear operating range.

 

[Aniket]

I wouldn't, by any stretch of imagination, call TPA3116/3118 crappy chips when implemented correctly and used in the linear operating range.

yes agree, when implemented correctly and with proper pcb layout it may sound fine.

but, if we come out of imagination, it is still crappy for "for hi-fi music listening"

i would consider TDA8922 over this if i have to go for a medium power class D chip

 

[SanjeevM]

yes agree, when implemented correctly and with proper pcb layout it may sound fine.

but, if we come out of imagination, it is still crappy for "for hi-fi music listening"

i would consider TDA8922 over this if i have to go for a medium power class D chip

Hmm... I would first do an actual shootout A-B blindfold comparison before I would comment on sound quality.

You could try out the Allo Volt or Volt+ amps which use the 3118D2 chips, if you dont like the cheaper Chinese builds. They are highly regarded.

Aniket, what are the THD% and SNR figures for the TPA8922C chip? I could only see talk of voltages and protection circuits in the spec sheet.

For 3116 they are 0.02% and 102dB respectively.