Raspberry Pi 3 Model B+ and the 4-pole stereo output

Audio Gear Talk RoPieee
1

So I was wondering, can I also use the Raspberry Pi 3 Model B+ default 4-pole stereo output instead of attaching an extra component?

I am about to purchase a second hand 3 B+ and in this specific scenario audio quality is not the most important.

I’d like to connect it to a speaker with 3.5 mm aux input.

2

The internal rpi audio is disabled by default using RoPieee and cannot be enabled

3

I can solve that by running Linux and manually install Roon Bridge?

4

Don’t know anything about Roon bridge anyway it think it’s possible, you can try with DietPi too

5

You can. Not sure you want to though, as the onboard Pi audio is notoriously bad.

6

Check. I’ll just purchase a simple usb cable and adapter to go.

7

Depends on what your definition of “notoriously bad” for a generic 16bit 44/48kHz codec is - I would certainly not use it for my main system, but had it running that way with Diet-Pi and Roon bridge on my kitchen Creative SoundWorks 745 boombox and couldn’t detect any bad behavior, but finally switched to Ropieee with 7" display and the cheapest HAT DAC.

8

What do you mean by “generic 16bit 44/48kHz codec”? Or did you mean “format”?

9

Sorry for the confusion, Marian.
I thought I remembered, that the BCM2837B PCM-audio-interface output is used in I2S mode to output to an onboard DAC chip, but just looking it up on the RPi schematic and browsing the BCM datasheet, they’re doing it via PWM from the hardware GPIOs instead, buffer and RC-filter that before the output terminal.
Sounded okay through the kitchen boombox…

1 Like
10

Thanks. I was a bit confused, as the term “codec” is usually used for software.

11

Many audio chipset manufacturers use the codec term to refer to ADC/DAC combined on a single chipset.

AJ

1 Like
12

Thanks, good to know. My hardware background is very limited. Does the Pi also have an ADC?

13

No ADC that I can see from the schematics. Nor any DAC chipset for that matter. From what I can tell, Raspberry Pi is using the digital audio stream directly to drive a PWM stage that is then output filtered. That seems to coincide with Marin’s second description above. But Marin’s earlier codec reference would appear not to apply.

AJ

2 Likes
14

Very Interesting. Sounds like a line-level, low-power class D amp. I’ll try to measure the analog output when I get some time - unless somebody already did that.

1 Like
15

There it is, I’d been mixing up hardware setup recollections from other microcontroller and RPi boards.