Ariadne Conill 🐰Mar 3
my focusrite scarlett 2i2 has started buzzing. grr.
Show threadAriadne Conill 🐰Mar 3
i am powering it via probably the shittiest possible usb-c cable. i wonder if getting a better cable would fix it.
Show threadAriadne Conill 🐰Mar 3

adding a powered usb hub did not fix it. so i modified a usb cable to let me splice in power from an external 5v psu.

*that* fixed it.

Show threadAriadne Conill 🐰Mar 3
this is a *server motherboard* ASRock. what are you even doing. why is there noise on the USB power rails.
Show threadGraham Sutherland / PolynomialMar 3
@ariadne asrock are terrible at this. every board I've had from them has noisy USB with audio frequency garbage coupled from the CPU power rails. my guess is they run 4 layer and let return currents flow right under the USB bucks and I2S DAC in most of their designs.
Show threadI love this, so IMar 3
@gsuberland @ariadne that, and USB VBUS is the second-worst voltage source that most people will use - the worst being automotive “12” volt
Show threadGraham Sutherland / Polynomial
@jpm @ariadne true, but still, I've seen >400mVp-p audio frequency noise across VUSB/GND on one of their boards. no common mode filtering either. hot garbage.
Mar 3 at 3:22amWeb
Show threadI love this, so IMar 3
@gsuberland @ariadne USB VBUS go eeeeeeeeeeeeeeeeeeee
Show threadI love this, so IMar 3
@gsuberland @ariadne and I'm still seriously considering designing and building a USB VBUS fixer (as big an input cap as I can get away with, a 1MHz-class buck-boost converter in the middle, and as big an output capacitor as I can afford)
Show threads0 Is Not A SysadminMar 3
@jpm @gsuberland @ariadne the irony is we have this issue specifically with the server motherboards that a certain high end audio console manufacturer uses in their consoles (no actual USB audio devices, but issues with USB HID and MIDI devices due to noisy/saggy VBUS)
Show threadI love this, so IMar 3
@s0 @gsuberland @ariadne speaking of your $DAYJOB, do you reckon they’d pay for a device called “The USB Power Unfuckenator” or should I workshop some more names?
Show threadDuncan BayneMar 3
@jpm @s0 @gsuberland @ariadne In a heartbeat. But my $DAYJOB folks are unusual (in a good way).
Show threadPaul_IPv6Mar 4

@jpm @s0 @gsuberland @ariadne

LOL.

depends. if you're selling directly to the engineering folks, it's perfect. if you're trying to get to a company big enough to have a purchasing department, you might need something a bit more... polished? :)