I currently have Up2Stream Mini V3 and Up2Stream Amp (Stereo). Both the products have the latest firmware.
I need help solving the following issues:
- On Up2Stream Mini V3, there is clean output (no noise/hum) for any gain only if it is powered from a separate, isolated power supply. If 5V supply is derived from the amplifier supply (24V), then the output is noisy. I have tried a LOW pass filter before the 5V regulator to no effect.
- On Up2Stream Mini V3, I have used the extension port to connect to my own back panel PCB. I have used the WiFi and Bluetooth LED and they work fine. I have also used the ‘Key’ exactly as mentioned in the reference diagram to implement the MODE push button which is not responding. Using the MODE push button, I hope to TOGGLE between Bluetooth and WiFi inputs.
Any inputs are much appreciated.
Hi and welcome to the forum.
So, just to confirm, both the issues relate to the mini?
With regard to the noise issue powering from your 24v amplifier supply, are you using a linear or buck converter to reduce to 5v?
And confirm with the push button selection, you are using a momentary push button switch, resistors R47 and R64 and capacitor C27?
Thank you for your early reply.
Yes, both the issues are related to the mini v3.
The 24V supply is linear. I am using a buck regulator based on LM2596. I can power RPi 4B with it. With the RPi, configured as an audio streamer, I can connect to bluetooth and use the headphone out and its very silent. No noise/hum issues.
If I replace RPi 4B with Mini v3, the noise starts.
I can confirm that I am using momentary push switch similat to the one on the board. R47 = 10k, R64 = 100E and C27 is 0.1uF.
I haven’t got an explanation on why your converter is okay with the pi but not the mini, a couple of points to consider though:
Forum member Ernst (KolfMAKER) has had a similar issue with his mini Up2Stream Mini & Ripple problem ? - #15 by Steve1
Buck converters, as all switching power supplies can be noisy, I would suggest you try a LC filter on the output and see if that helps. I did some tests about 12 months ago and published them on the forum.
Power supply selection - #3 by Steve1
The push button should work, maybe double check your wiring and make sure you have the correct pins on the JST connector.
Hope this helps.
I did try an R-C filter with no effect. I will give an L-C filter a try.
I also have Up2Stream Amp (2.0). Its the same. Output is noisy when I power it with linear 24V power supply. To get a better s/n ratio I have to reduce the streamer gain but then I fall short of output power.
To me it appears to be the case similar to the mini v3: Non isolated power supplies used to power both the streamer and the amplifier.
Let’s see where this goes.
Thanks Steve for your inputs!