Modded RPi4 Board for better SQ?

tho i should also say that i tinkered a bit software wise with moode (to reduce jitter, and overlcocking the cpu is a easy way to reduce cpu jitter (tested with jitterdebugger) but that was clearly not the way togo sound-wise, underclocking did way more) and i actually believe you guys that cpu/os jitter isnt the main concern but i actually think noise/power/shielding is a main concern here (well relatively speaking) i just wanna optimize it as far i can and have a little fun while still being on the cheap side (compared to the allo usb bridge, which has the big disadvantage of still using the cm3 imo tho)

tho maybe i change my mind after using a usb isolator, i will test this first :)
 

TNT

Member
Paid Member
2003-04-26 10:25 pm
Sweden
If you fund that noise seem to be the main contributor and that reducing it seem to improve SQ, then your whole topology is the wrong one.

The lowest possible noise is to move any switching unit as far away as possible from the DAC and use a signal conveyor that dont pick up noise and is of low bandwidth. Toslink is such an interface but it must be used in conjunction with a DAC that recreates a clock locally (requires a PLL) for low jitter.

Some report the sound when using an opto link to be "boring / dead"... If one have tuned a system to sound "good" with a noise infected DAC, once this is removed by e.g. using Toslink (opto), the experienced "deadness" stem from the previous need of tuning (amps, speaker ...) to tolerate the sound.

Its all a system game...

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The lowest possible noise is to move any switching unit as far away as possible from the DAC and use a signal conveyor that dont pick up noise and is of low bandwidth. Toslink is such an interface but it must be used in conjunction with a DAC that recreates a clock locally (requires a PLL) for low jitter.
actually i still wonder about this, since many are afraid of jitter from toslink (tho i couldnt test it so far with my topping d10) but i think toslink would be "far" superior to usb on my windows machine, maybe a usb isolator will help here too i cant "really" confirm yet but i just cant bear the windows sound compared to moode with raspberry pi, i always contributed that to a too poluted pc, tho on the same pc windows also sounds worse compared to a tweaked linux system (tho pulseaudio sucks too... >.< for convenient its great, for sq not so much) but with my soundblaster Z and "cheap" headphones i also dont hear that stuff, just with my main setup (which still is fairly cheap... topping d10+presonus eris e8)
the eris e8 also show polluted systems very easy, with a nice audible hiss, a DI-box helps (with ground-lift) tho with my rpi setup i dont need it anymore and i found the DI-box actually changing the sound somewhat to the worse

the first thing i get is the topping hs01 usb isolator, i will report how it changes sound before i start this project here (and will test it windows vs moode)
i think a good test would be also a underclocked vs overclocked rpi, since i can kinda clearly hear changes here, would be great if the sound stays the same with the isolator, tho i kinda dont hope so or i wasted my time so far x)

i also wonder about people who claim a "too analytic"/non musical sound and so on with isolators, emi filters etc personally with my studio monitors as main setup i always strive for a "neutral" sound (with slight (like 1,5-2,5db) attentuated highs for less fatique/sibiliance)
but i kinda had a similar expierence with too many ferrite beads on power lines of my active speakers, some of these kind of changes "do something" but you (or atleast me) cant put your finger on what is actually the "true sound", its really more of a preference kind of thing

atleast what i noticed, kinda specially with usb filters/usb cables (and side-injected power instead of usb power) is that overall the sound gets more pleasent to listen to specially in long sessions (atleast i think thats why people also say it sounds more analogue compared to digital, me included), you dont get that "ah i had enough for today" feeling (specially with "higher" volumes like 75-80db) or even ear/brain fatique (beside the usual better soundstage, clearer highs/bass/voices etc)
to be honest i was just to cheap so far to buy one of those 300€ usb isolators for my 600€ setup x) but topping finally released a affordable galvanic isolator, which supports high speed usb 2.0, actually now saying it, i did test one of the 1.1 isolators, tho windows still sounded inferiour (i did test it with wasapi in the qobuz client) and on linux the 1.1 isolator doesnt work with the topping d10, since it uses 32bit by default on linux and i couldnt find a way to set it to 24bit, well you can set pulseaudio to 24bit for example but alsa still communicates over 32bit with the dac
Some report the sound when using an opto link to be "boring / dead"... If one have tuned a system to sound "good" with a noise infected DAC, once this is removed by e.g. using Toslink (opto), the experienced "deadness" stem from the previous need of tuning (amps, speaker ...) to tolerate the sound.
this would indeed explain some of the "unlogical" (subjective) expierences


tl:dr i will see what the usb isolator does on my rpi setup first :)
 
Last edited:

TNT

Member
Paid Member
2003-04-26 10:25 pm
Sweden
Yes, toslink adds jitter due to its limited bandwidth. This is physics. Thats why one need to see to that the clock used for D/A conversion is being recreated to have a low jitter. But you get rid of any other noise. I.e. you could have save the cake as well as eat it :)

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