Was doing a little research on finding the cheapest way to attach a Roon Bridge to a clock radio with AUX and thought I’d ask the community.
Requirements:
All new parts.
Same power requirements as radio (110v always on operation).
Must run Roon Bridge (RAAT).
Must provide analog (phono or RCA) outputs to clock radio.
Total bridge device must not be larger than clock radio (minus power supply).
Must support Wifi at a reliability to do 16/44.1.
Here’s my idea for a build with all pricing current MSRP of this post:
Pi Zero W kit (board, case, sd card, GPIO header, power supply) $28 - $38
HiFi Berry DAC+ Zero $14
RCA to phono cable $3
3D Printer for custom case to fit Pi Zero + DAC HAT $400
** Total $445 to $455
I’ve told my wife there is no cheaper option and all these parts are required to get Roon onto the clock radio. She has stoped talking to me about this project so I thought the community could help. Do you think there is a cheaper option? Have I budgeted enough for the printer?
All joking aside… minus the 3D printer, which I’m trying to convince we need, do you have other suggestions than the Pi Zero W and the HiFi Berry Hat? At ~$45 that seems like the cheapest option I can find without constructing my own audio circuit on the Zero (which is a little beyond my skill level). It’d be a bit cheaper (a Zero W board is $10 on its own) if I wanted to just mount the Zero on the cardboard box it comes shipped in but I’m not sure I want it that exposed.
Enjoy your weekend and thanks for your suggestions.
Chromecast Audio. Done. I have one (actually 3 but two are still in box) in use feeding a little amp in a reading nook via analog. Works reliably on 24/96 content.
Thanks for this. I didn’t start using Pis until the 4 was almost released. Did some digging and Zero is 3 generations back. It’s not because its 32-bit (as I don’t believe 64 bit is required) but the architecture is:
For reference:
Pi Zero W ARM1176JZF-S. This is ARMv6 architecture. ARMv6 was introduced into the Raspberry Pi range on the Raspberry Pi B SBC in 2012.
Pi 2 Cortex-A7. This is ARMv7-A architecture (32-bit). This architecture and the CPU on the 2… more details at the end*. This was introduced in 2015.
Pi 3 Cortex-A53 64-bit. This is ARMv8 architecture. ARMv8 was introduced into the Raspberry Pi range on the 3 in 2016.
Pi 4 Cortex-A72 64-bit. This is also ARMv8 architecture.
Roon supplies 2 Roon Bridge downloads for ARM architects: arm7hf and armv8
So… now someone gets to correct me but… Bridge should be compatible with any 3 or 4 Pi as those are v8 architecture. Bridge should work on any armv7 based cpu that has a floating point processor (thats the _h_ard _f_loat in the file name). This means bridge *should work on a Pi 2? But it won’t work on the zero.
I’ve decided to get a Raspberry Pi 3 A+ for this project. It’s a $25 board and includes the 3.5mm stereo phono jack. That makes it cheaper than my original shopping list. I’ll update in a week if anyone wants to know how it preforms.
In conclusion… the cheapest Bridge that meets my qualifications appears to be a Pi 3 A+, mount it on the cardboard its shipped in, get a cheap power supply, get a cheap microSD card, you should have a bridge for somewhere near $35-$45.
Yes… my clock radio already “sounds like crap” I don’t believe the streamer is going to make it sound worse. If it does, then I’ll add a HAT. Test, improve, test again. Hail science!
Haven’t compared the 3A+ to the 3B+, but the latter sounded quite okay on DietPi RAAT Roonbridge with a Creative SoundWorks 745 in my kitchen… that said, the RPi 1B+ 3.5mm output indeed sounded like crap!
How does it sound?
Not great! But we knew that. It is audibly noisy with clicks and crackles in the high frequencies randomly but predictably. This whole set-up would see a significant upgrade with a DAC HAT which I will do eventually. For background music it meets my expectation and at lower volume, when across the room, I don’t notice it. One of the things I didn’t think about is that the volume on the Pi is set at 100 so I can use the volume on the radio. This amplifies the noise and makes using a DAC HAT a really good idea. If I was controlling volume from ALSA I don’t think the noise would be such an issue. The other thing I didn’t realize is that all Pi’s use a TRRS 3.5mm plug so they can supply composite video out this port + audio. That’s the proverbial nail in the coffin to getting any clean audio out of the Pi’s 3.5mm.
Notes (and why the 30-pin):
After starting this post I had the idea to use the Apple 30-pin connector on the radio to power the Pi; saving a power brick. I also thought, maybe, the radio would tie the analog audio pins of the 30-pin to aux and 1 cable would get me both power and audio. Well, the power worked! The radio supplies a nice 5v across the 30-pin at all times, even when off, and that is working great (no low voltage warnings). However, I couldn’t get any audio to work via the “iPod” input as it kept searching for an iPod and then went into standby. I had to use the 3.5mm AUX jack on the back of the radio. Everything else worked as expected.