Underclocked Pi 4: The perfect low-budget ($77) USB Bridge?

https://community.roonlabs.com/t/ropieee-on-raspberry-pi-4/91848?u=jim_f

Mine was $74

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I have the same setup as you have here, Pi4B 2Gb in a Flirc case, however i power mine with a different switched wall wart, not very audiophile at alll.
My various Pi’s have always been underclocked/powersave mode and i have NEVER EVER had any issues with the audio stream dropping out or any audible ticks or pops. My Pi4 is also always at 39°C!?
(First one, i fried due to heat)
While they all perform very good and to 90% satisfaction soundwise, they can quite easily be bettered, but at a cost.

I just wish @Dan_Knight would let us have a slightly more modern kernel in most distributions, but i respect his decision to support stability over features every day of the week! :slight_smile: Great distro!

Purely as a Roon Bridge, what new kernel features are needed for your Roon audio purpose?

Support for native DSD with various DACs primarily! But this is mostly cosmetics, i am really content with the DSD128 all of my DACs support over DoP.

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I have found using 25000ma battery pack has worked wonders for improving my pi’s that I use with headphones. I got a usb inline power switch so I don’t have to keep pulling out the cable and the battery outputs 3a so the pi’s running nice and smooth and as it’s not on all the time it lasts about a month between charges. Battery cost me 29.99 from Amazon and it sits under the pi. I have found my pi4 runs hot even with a heatsink attached but it does have a hifiberry DAC+ attached which I am not using so may look to get the flirc case instead.

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Here is what I run mine with (NAA renderer), very much underclocked. This is from config.txt

#Serious underclocking
force_turbo=1
arm_freq=600
arm_freq_min=600
gpu_freq=150
core_freq=200
core_freq_min=200
h264_freq=200
isp_freq=200
v3d_freq=200
sdram_freq=300
sdram_freq_min=300
avoid_pwm_pll=1
over_voltage=-8
over_voltage_min=-8
over_voltage_sdram=-8
over_voltage_sdram_c=-8
over_voltage_sdram_i=-8
over_voltage_sdram_p=-8

#Disable HDMI, WiFi and BT
hdmi_blanking=2
dtoverlay=disable-wifi
dtoverlay=disable-bt

#Disable LED
dtoverlay=act-led
dtparam=act_led_trigger=none
dtparam=act_led_activelow=off
dtparam=pwr_led_trigger=none
dtparam=pwr_led_activelow=off

#Turn off ethernet port LEDs
dtparam=eth_led0=4
dtparam=eth_led1=4

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Any form of CPU throttling will likely cause hickups every now and then, which is why I use fixed frequency. From DietPi, I think you can set performance and then lower the normal and min frequency to achieve this. Or use config.txt like above

Any ideas if Ropieee is underclocked, I ditched dietpi as it’s too flakey when updating for my liking.

I don’t know about that, but RopieeeXL works great “out of the box.” I leave it on all the time.

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Wow, that IS some serious underclocking. Is this DietPi, or something else? Can the config.txt be edited after first boot?

I plan to try this tonight!

Are you guys using USB2 or USB3 for your DAC? What was your rationale?

I’ve tried both and can’t tell any difference so I’m using 3.

I think config.txt is for all Linux versions, and you can access that file from PC if you put the SD card in an USB adapter and into PC.

Not sure if I could hear any difference though, I felt the sound more open but might be bias. But it seems fast enough for 768khz and batteries lasts longer to it seems to work.

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@spockfish is any of what @Magnus mentions here available in Ropieee for the Pi4?

I’m not sure what you mean with ‘any’, but I assume you mean under-clocking.

Not at this moment. I played around with it, but that’s about it. Never received a request for it, so maybe I should add it to the todo list and provide it as an ‘advanced’ option.

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If there is an improvement in sound it would probably be worth it.
Also the LED section is interesting. I am finally getting some use on my 3b (waiting for a Pi 4 as I use a USB DAC). The red power LED and the blinking ethernet LED is quite annoying. I turn the Pi off for the night. With disabled LED’s I could leave it running (with the reboot schedule during the night)

I leave my Pi 4 on all the time.

I always keep all my Linux boxes running, but the Pi is in our living room so the LEDs are disturbing. I had a microRendu in this spot before. No LEDs and no problem…