Dear SA,
I think you would be spending too much money in the wrong place.
Powering the RPi by such ultracapacitors would give little benefit as you are still powering the dirty side of the system.
Although your power will be super clean the RPi itself is a high frequency noise generator due to all the kHz / MHz signals running over the board.
My personal feeling is if you avoid a noisy power supply like all these standard RPI supplies via USB are SMPS type of supplies without good filtering.|
If you would change that to a linear regulated PS, even an LM317 or higher current variant would be sufficient you already reduced the PS noise significantly.
I have read once (could not find it anymore) that if you use LM317 with 2 green LED's you already have a very decent PS.
Behind the LM 317 you have 2 resistors, one for the 1,25 Volt reference and below the resistor for setting the actual voltage.
If you replace the lower resistor for 2 green LED's of 1,9 - 1,95 Volt each you have very good performance of an LM317.
Please use your expensive capacitors on the clean side of your system.
@Ghostship Does the RPi5 offer any advantages over the RPI4 in terms of sonic quality? Or are there any other advantages that we should probably take into account?
Thanks.
Thanks.
I have seen reports that SQ is better. Also, the RPi5 has the benefit of using up to 2TB M.2 SSD with much better performance than running off of the microSD, the USB 3 has more total bandwidth for much faster transfer speeds, and the processor is 3x faster than previous versions. I have one on the way, so no personal impressions yet.
Ok. I only know what I copied directly from their website here: https://www.raspberrypi.com/products/raspberry-pi-5/
Other sources say the differences between the RPi5 and RPi4 are:
- faster processor;
- faster Ram with increased bandwidth;
- improved faster VideoCore VII GPU that is clocked at 800MHz and supports OpenGL ES 3.1 and Vulkan 1.2;
- new RP1 I/O chip that increases bandwidth and takes the load off the CPU, to the benefit of storage devices, USB, and other peripherals;
- microSD port has double the speed;
- the RPi 5 has faster USB3 ports because it has dedicated 5Gbps available for both the ports courtesy of the RP1 chip, the two USB 3.0 ports of the RPi 4 share the available bandwidth of 5Gbps between them;
- the RPi5 has a PCIe connector allowing for an M.2 drive HAT;
- the RPi5 has two 4-lane MIPI ports for cameras and displays, whereas the RPi4 only has one 2-lane camera and one 2-lane display port, doubling the lanes helps support devices with bandwidth up to 1.5Gbps like cameras with a higher bit-rate or LCDs with higher resolution; and
- The Pi 5 has a dedicated UART connector, with the Pi 4 you need to use the GPIO pins for UART debugging.
I am getting nowhere fast on this. I can attach all dc cables to the case and get everything to light up except one side of the linear Pi duo. For this one cable only, I get the LinearPi to work fine if that cable is hanging free of the box, but if I screw it into the box I get the dim/flashing red LED and distortion.
For the errant cable, I have tried cutting it short and resoldering with a new dc connector as suggested by @trekpilot (thanks for the suggestion) but to no avail. After all the effort I’ve put in, I don’t want to end up with one cable just hanging out of the box when everything else is screwed neatly into place. Any more suggestions I can try?
@Philip Kent
Would it be possible to take 2 pictures and post them here - one of the working setup and one of the non-working.
Based on your original post I woud say you have some sort of a short cirquit or additional contact caused by the back panel made of metal. However, in your last post you rather discuss a hanging cable. There is a reason for the saying "one picture is worth of thousand words".
Would it be possible to take 2 pictures and post them here - one of the working setup and one of the non-working.
Based on your original post I woud say you have some sort of a short cirquit or additional contact caused by the back panel made of metal. However, in your last post you rather discuss a hanging cable. There is a reason for the saying "one picture is worth of thousand words".
Thank you for the interest in my infuriating problem, @crossride! Here are 2,000 words’ worth of photos! Photo 1 with one wire from the LinearPi duo unattached to the case shows full power. All modules are in the “on” position.
Photo 2 is exactly the same except for now the wire is screwed into the case. All modules in “on” position again. Note the LEDs on input and output in the left hand LinearPi duo are now very faint. In reality they pulse from fully off to faintly
on.
Photo 2 is exactly the same except for now the wire is screwed into the case. All modules in “on” position again. Note the LEDs on input and output in the left hand LinearPi duo are now very faint. In reality they pulse from fully off to faintly
on.
Did you measure the actual vaoltage on the input of the power supply board?
If that is not stable I suspect the cable running from the back panel, or maybe the input connector on the back panel has a bad contact.
Do you have a volt meter ? It is one of the minimal tools you would need when doing DIY electronics even if it are ready made building blocks
Have you tried making another cable with input connector ?
If that is not stable I suspect the cable running from the back panel, or maybe the input connector on the back panel has a bad contact.
Do you have a volt meter ? It is one of the minimal tools you would need when doing DIY electronics even if it are ready made building blocks
Have you tried making another cable with input connector ?
Thanks @Oystein I have a volt meter. The voltage on both LinearPi inputs is between 9.3v and 9.4v with the switch off. When I turn the switch on, the right hand linearPi remains stable at 9.3v but the left hand module is pulsing randomly between 0.8v and 1.5v. I have already tried resoldering a new input connector and I checked the wires for continuity before and after remaking the cable. I suppose I could do it again with completely new wire? The thing is: I can’t reproduce the fault with the cable loose from the case, even when wiggling it. If it was a dry solder or other loose connection it should show up then, right?
It seems the issue lies with the type of connectors you're using when mounting them to the case. Based on what I see, your case is attached to the negative pole of your Raspberry Pi, FifoPi, etc. Then, you connect your input power to the same ground, effectively connecting your Linear Pi input to the output.
so all the blue lines terminals are connected see photo attached. I am surprised you have not damaged anything.
I recommend using different connectors altogether for all components, or at the very least, changing all your power input connectors so they do not connect to the ground. It's important to note that your connector's metal screw is connected to one of the two wires of the input (black wire ), if the metal screw is not connected to anything then ignore all this.
hope this help you see what I am trying to say.
so all the blue lines terminals are connected see photo attached. I am surprised you have not damaged anything.
I recommend using different connectors altogether for all components, or at the very least, changing all your power input connectors so they do not connect to the ground. It's important to note that your connector's metal screw is connected to one of the two wires of the input (black wire ), if the metal screw is not connected to anything then ignore all this.
hope this help you see what I am trying to say.
The easiest is change them all to something like this so you can keep the same layout and holes
Plastic housing connectors isolated from chassis
😊
https://amzn.to/494BwvX
Plastic housing connectors isolated from chassis
😊
https://amzn.to/494BwvX
Thank you @Gabster 2000 for going out of your way to explain with annotations! I did wonder about this before, although the permutations of grounding scenarios do challenge me. The case is aluminium and I sprayed the black surface of the back panel with a non-conductive paint, including inside the holes I drilled for the connectors. I tested for continuity before I connected anything. When this problem appeared, I checked the hole of the cable causing problems and found some of the paint had rubbed off and I had continuity when I tested with my DMM. I wrapped the hole in electrical tape and the connector with PTFE tape to try to isolate it temporarily, but I still had the problem. I then inspected the holes in my other connectors and realised that they had paint rubbed off too, so I ruled it out as a specific problem to this connection.
Anyway, I will change the dc connectors on all cables for the ones with plastic housings and see if this does the trick. Thanks again for your help.
Anyway, I will change the dc connectors on all cables for the ones with plastic housings and see if this does the trick. Thanks again for your help.
Also to add: I have previously assembled an IanCanada streamer housed in a bare aluminium case, using the same connectors. I thought I was on safe ground with these. Anyway, I do appreciate my limitations and will go with the suggested change of connector and report back. Hope this thread helps other novice builders. I am trying not to get too far over my skis, but staying within comfortable boundaries as I build my knowledge is a constant challenge. The upgrade path is long and tempting!