Your vocabulary is confusing - however you defend it.. just so you know...
If you are just basically guessing, I think you should have stated that in the beginning of the thread...
Me, I'm just feedbacking on your statement from post #1: "Has someone some ideas or sees errors with this?"
So don't be offended - you got what you asked for.
//
If you are just basically guessing, I think you should have stated that in the beginning of the thread...
Me, I'm just feedbacking on your statement from post #1: "Has someone some ideas or sees errors with this?"
So don't be offended - you got what you asked for.
//
No problem, everyone has to decide for their own if they want/need something like this
for my part, im sick of different usb ports, usb hubs, usb cables all changing the sound and i think it has alot todo with filtering
i get your POV but thats why i created this, to make a somewhat low cost solution
Just to wanna give a little background story
i bought this pcie card: https://de.aliexpress.com/item/1005005901937820.html
difference to the mainboard out was minimal i would say... but i wrapped this thing like this: https://www.head-fi.org/threads/best-low-budget-pcie-usb-card.972643/post-18119864 and placed some ferrite clamps on the sata cable going to the pcie card, these two tweaks actually made the pcie card sound better compared to mainboard usb, i get the feeling that only EMI/RFI is changing how usb sounds...
i also placed more ferrite clamps on the cables i use... i currently use a ifi isilencer + 2m cable + 30cm cable + diy filter + 50cm cable ... on each cable end placed a ferrite clamp, so 6 in total.... with 8 i get the first dropouts, this also improved things greatly
Now... with all these EMI/RFI tweaks you may noticed how high frequencys of your hifi get "tamed" and you can kinda reach a point where the sound "sounds dead" IMO this is the "standard" you wanna reach... after you reach that point, adjust your EQ accordingly to compensate some of the "dead sound" but it seems like emi/rfi is specially boosting high frequency audio (it always sounds like 10-20khz is affected) and we you get used to it you may even prefer it....
Now if someone is under the impression ferrite beads affect sound "negatively" and what you hear is not just a side effect of filtering EMI/RFI, then i accept your opinion but its after some testing atleast not mine opinion
i actually used a house curve for 2 years with tamed highs above 5-10khz ... (around -6db at 20khz) ... with many EMI/RFI tweaks i was able to adjust the housecurve (after the sound "deadening") now to only -3-4db at 20khz .... imo this speaks words
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this is that... now what i wanna get to:
someone in the head-fi thread recommended to use ifi isilencers and such filter directly in the pcie card
now this has actually a big pro:
1. my diy filter injects a external power supply, so the power filtering properties of the ifi isilencer are pretty much useless placed before the diy filter, when placed inside the pcie card, it can atleast clean some of the power used by the pcie card.... this seems to affect things positively
i also placed a chinese power filter https://de.aliexpress.com/item/1005005201924413.html (this thing filters only power as it seems) into the second usb slot of the pcie card... again this seems to affect things slightly (the ifi isilencer made a 2-3 times bigger difference here, i dont recommend getting this filter, its crap for the price unless you want a aluminium case and only wanna filter power lines)
Now to the point... i wanna add some power filtering for the sister board for the above reason
a simple solution would be one larger cap like 470uF + 0,1ohm wire resistance and we get a lowpass filter with the -3db point at around 3khz, i guess this is still enough to affect things positively, tho no real comparison for a 1,5F supercap getting us a -3db point at 1hz BUT i think a supercap cant be used efficiently here, when i put a current limiting power switch in between i dont think the supercap is able to "backfeed" the pcie card... a simple (unprotected) cap would be able to
we could also add larger caps like 680uF (2300hz) or 2x 470uF (1700hz)
i bought this pcie card: https://de.aliexpress.com/item/1005005901937820.html
difference to the mainboard out was minimal i would say... but i wrapped this thing like this: https://www.head-fi.org/threads/best-low-budget-pcie-usb-card.972643/post-18119864 and placed some ferrite clamps on the sata cable going to the pcie card, these two tweaks actually made the pcie card sound better compared to mainboard usb, i get the feeling that only EMI/RFI is changing how usb sounds...
i also placed more ferrite clamps on the cables i use... i currently use a ifi isilencer + 2m cable + 30cm cable + diy filter + 50cm cable ... on each cable end placed a ferrite clamp, so 6 in total.... with 8 i get the first dropouts, this also improved things greatly
Now... with all these EMI/RFI tweaks you may noticed how high frequencys of your hifi get "tamed" and you can kinda reach a point where the sound "sounds dead" IMO this is the "standard" you wanna reach... after you reach that point, adjust your EQ accordingly to compensate some of the "dead sound" but it seems like emi/rfi is specially boosting high frequency audio (it always sounds like 10-20khz is affected) and we you get used to it you may even prefer it....
Now if someone is under the impression ferrite beads affect sound "negatively" and what you hear is not just a side effect of filtering EMI/RFI, then i accept your opinion but its after some testing atleast not mine opinion
i actually used a house curve for 2 years with tamed highs above 5-10khz ... (around -6db at 20khz) ... with many EMI/RFI tweaks i was able to adjust the housecurve (after the sound "deadening") now to only -3-4db at 20khz .... imo this speaks words
---------------------------
this is that... now what i wanna get to:
someone in the head-fi thread recommended to use ifi isilencers and such filter directly in the pcie card
now this has actually a big pro:
1. my diy filter injects a external power supply, so the power filtering properties of the ifi isilencer are pretty much useless placed before the diy filter, when placed inside the pcie card, it can atleast clean some of the power used by the pcie card.... this seems to affect things positively
i also placed a chinese power filter https://de.aliexpress.com/item/1005005201924413.html (this thing filters only power as it seems) into the second usb slot of the pcie card... again this seems to affect things slightly (the ifi isilencer made a 2-3 times bigger difference here, i dont recommend getting this filter, its crap for the price unless you want a aluminium case and only wanna filter power lines)
Now to the point... i wanna add some power filtering for the sister board for the above reason
a simple solution would be one larger cap like 470uF + 0,1ohm wire resistance and we get a lowpass filter with the -3db point at around 3khz, i guess this is still enough to affect things positively, tho no real comparison for a 1,5F supercap getting us a -3db point at 1hz BUT i think a supercap cant be used efficiently here, when i put a current limiting power switch in between i dont think the supercap is able to "backfeed" the pcie card... a simple (unprotected) cap would be able to
we could also add larger caps like 680uF (2300hz) or 2x 470uF (1700hz)
Just builded this with 2 Panasonic Oscon 470uF 16V (i think they are SEPF) to test things in the free pcie card usb slot ...
first tests seem to show that this one clearly beats the chinese usb power filter in the second (free) usb slot
i also fixed the capacitors to the usb port with UV glue... to make it somewhat usable
i will burn this one in for 24 hours and test again
i created yesterday a 1x 470uF version of the same plug, since there first version had uncured uv glue inside which kinda leaked out making a mess
comparison was done today like this:
Ifi isilencer unplugged, usb cable into one slot of the usb pcie card, in the other sockets i tested these three:
imo the chinese one doesnt do much good, ifi isilencer was best here but the 470uF cap connector wasnt far off imo and even seemed to improved bass response over the ifi isilencer, but audibly overall the ifi isilencer did a bit more
my guess is that shifting the frequency down a bit further with more capacitance might improve things but the 470uF cap seems todo already "quite alot" on its own with a cutoff frequency around 3khz
when i place the ifi isilencer before the usb cable than the differences in the filters in the second usb port were diminished (the chinese one pretty much inaudible and while the 470uF DIY plug still improved things (a bit) i would say the effect was diminished with the ifi isilencer in the main slot, which kinda makes sense)
Tho also the ifi isilencer did a lot more on the usb cable than in the second plug... since i guess it also filters datalines... i kinda wonder whether i can reach a point where the ifi isilencer doesnt improve things anymore
comparison was done today like this:
Ifi isilencer unplugged, usb cable into one slot of the usb pcie card, in the other sockets i tested these three:
- 1x 470uF DIY plug
- Chinese "Quick Silver" power filter
- Ifi Isilencer
imo the chinese one doesnt do much good, ifi isilencer was best here but the 470uF cap connector wasnt far off imo and even seemed to improved bass response over the ifi isilencer, but audibly overall the ifi isilencer did a bit more
my guess is that shifting the frequency down a bit further with more capacitance might improve things but the 470uF cap seems todo already "quite alot" on its own with a cutoff frequency around 3khz
when i place the ifi isilencer before the usb cable than the differences in the filters in the second usb port were diminished (the chinese one pretty much inaudible and while the 470uF DIY plug still improved things (a bit) i would say the effect was diminished with the ifi isilencer in the main slot, which kinda makes sense)
Tho also the ifi isilencer did a lot more on the usb cable than in the second plug... since i guess it also filters datalines... i kinda wonder whether i can reach a point where the ifi isilencer doesnt improve things anymore
depending on how the ifi isilencer filters the datalines the filtration might even improve things in the second slot bringing the noise of the usb chip further down, so maybe thats some of the difference i heared
i think a common mode choke would not do anything as long there is no device hooked up, making the sister board maybe inferior to something like the ifi isilencer used in additional ports
i think a common mode choke would not do anything as long there is no device hooked up, making the sister board maybe inferior to something like the ifi isilencer used in additional ports
This new revision of the main filter should solve all possible issues in terms of user friendlyness
the two relais consume around 22mA each and get powered by a external power supply (where keeping the 500mA limit of usb ports isnt nessecary)
these two relais switch:
1. switch the current limiting resistor of the power switch from 1A-1,8A to 500mA
2. a GND / CleanGND passtrough (since its not always safe to use PC Power with resistance between grounds, the passtrough is disabled as the external power supply is plugged in)
3. switch from PC Power to EXT Power (these signal relays can do up to 1A, so i used both contacts of one relay for theoretical 2A with 1A - 1,8A limit)
then there is a switch (SW1) to switch between 100 and 330 ohms between grounds when the external power supply is used, for me with multiple dacs i was able to use 333 ohms reliably, so i think these are good values
the power switch, for current limiting, so we can use 4x 1,5F 5V caps with no problems, also with PC Power in theory
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the thing i still question is if i should offer a "PC Power" option at all, since it also bypasses the ground resistance making the filter way less optimal imo
this was only a draft i did, so this is not final yet
and one update on the sister board:
i removed the shield termination resistor and made this dongle "transparent" in terms of shielding scheme, i think this will be the better approach
main thing which made me think otherwise: the pcie usb card i bought explicitly connects shield of the usb connectors to PC case ground, with this dongle shield stays "shield" and is not connected to the "clean gnd"
termination on the other (dac) end is another thing tho
---------------------
i will probably soon buy some of the sister boards and my lan isolator to test things before i order the next revision of the main filter
i removed the shield termination resistor and made this dongle "transparent" in terms of shielding scheme, i think this will be the better approach
main thing which made me think otherwise: the pcie usb card i bought explicitly connects shield of the usb connectors to PC case ground, with this dongle shield stays "shield" and is not connected to the "clean gnd"
termination on the other (dac) end is another thing tho
---------------------
i will probably soon buy some of the sister boards and my lan isolator to test things before i order the next revision of the main filter