Careful where you site that Pi4 streamer...

Tony_J

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I almost hesitate to post this but...

Playing my new 3-way crossover setup (https://www.hifiwigwam.com/threads/diy-3-way-analogue-crossover-with-gainclone-amps.117232/) this morning, I noticed that when changing tracks, there was noticeable "hash" overlayed on the beginning of the new track for a second or two. With the rather Heath-Robinson setup I have at the moment, the R-Pi4 streamer was sitting very close to the heatsink for the chipamps on one channel, so I moved it as far away from the two crossover/amp boards as the cable would allow. Noise very much attenuated/eliminated. Bringing the Pi4 box as close as I could get it to the power amp circuitry on the component side of the board, noise very much louder and not confined just to changing tracks.

Just goes to show that in some types of equipment, siting of the Pi relative to other bits can make a big difference.
 

StingRay

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I almost hesitate to post this but...

Playing my new 3-way crossover setup (https://www.hifiwigwam.com/threads/diy-3-way-analogue-crossover-with-gainclone-amps.117232/) this morning, I noticed that when changing tracks, there was noticeable "hash" overlayed on the beginning of the new track for a second or two. With the rather Heath-Robinson setup I have at the moment, the R-Pi4 streamer was sitting very close to the heatsink for the chipamps on one channel, so I moved it as far away from the two crossover/amp boards as the cable would allow. Noise very much attenuated/eliminated. Bringing the Pi4 box as close as I could get it to the power amp circuitry on the component side of the board, noise very much louder and not confined just to changing tracks.

Just goes to show that in some types of equipment, siting of the Pi relative to other bits can make a big difference.
You should buy one of those pods, only £850, may solve this issue.

Siting can be an issue, had some hum from some tubes once with units close together, moved them 2 feet apart, hum gone.
 
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Tony_J

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Looks like the crossovers/amps are also sensitive to noise from my mobile phone. I feel a metal case for them coming on...
 
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Nopiano

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It’s good that this was readily audible, Tony, as you could set about a fix straight away. I’m sure that lots of “digital stuff” can mess up an otherwise good sounding system and it makes sense to consider how much effort from commercial manufacturers goes into casework, power supplies and such-like. Even then, some care about positioning and cables surely repays such attention.

When turntables and phono stages, or even cassette decks, were popular, I recall using these as ‘probes’ to test nearby noise. (I installed systems on Saturday afternoons/evenings) Pop a cassette in, press play and pause, and turn the volume up to say three-quarters - then as you move the paused deck around you hear hums and buzzes until you find where to place it in a rack or on a sideboard. Same with turntables once wired up.
 
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Music At Home

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You need to try using a portable AM radio as a “sniffer” around something like a RPi, anything with a switch mode power supply in it, or the cables leading to and from these pieces of equipment. The typical wall wart power supplies used to power RPi’s and similar are shocking! Once you get a feel for how much muck these things chuck out you’ll never want to let them anywhere near a HiFi system again.

If you have a few 5v wall-warts knocking about you can use the AM radio test to pick the least offending.
 

bencat

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Ah I solved it by replacing any SMPS psu with LPSU it has greatly increased the box count but it has also greatly improved the music so to to my ears a result .
 
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Tony_J

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Ah I solved it by replacing any SMPS psu with LPSU it has greatly increased the box count but it has also greatly improved the music so to to my ears a result .
The noise I was hearing changed as the Pi changed what it was doing - changing tracks etc., so wasn't PSU-related. The Pi itself (and in this case the DAC HAT attached to it) is quite capable of chucking out noise all on its own.
 

bencat

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Tony in my case I have a separate Pi 4 that does nothing but LMS duties powered by an LPSU and connected to my switch which has SFP in put . The Pi sits on a shelf on its own in one of the spare bedrooms and truthfully is silent . I can remember clearly the reduction of back ground noise that resulted as other items in my system had the SMPS supplies replaced . Also my Pi is in an Aluminum case with both heat sinks for the main chips and mesh RFI protection sheets on top bottom and sides . I know this is over the top and probably not needed but I value the quality of what I am listening to now and try and ensure it stays as quiet and interference free as possible . I agree with you that because of the very cheap and skeletal nature of a Pi it does need care in both placement and clean power supply .
 
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Strider

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I'm sure if were to make a difference but my main Rpi 4 is fully encased in a diecast enclosure/heatsink and I can't say its ever caused an issue wherever I place it on the kit shelves, the Rpi RaspDac kit (lovely looking thing) is also a diecast/machined aluminium enlosure and not any issues with that either. Maybe its a naked Pi with I2S hat that's the reason for the interference?

I must admit that it's the only device that I've replaced the wallwart SMPS with a LPS - a dual output one leg for the Pi and the other for the DAC.
 
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