andrewinukm
Head-Fier
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- Jan 30, 2010
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Oh, you're in UK. You should check out iFi iPower (5V). A really clean switching power. Someone at Computer Audiophile forum did a test between iPower vs Chinese linear power supplies. The iPower's noise level beat all LPS in the test.Yes, it's a switching power supply. I can't seem to find any linear power supply for less than £60 ($70?) and the ones I can will take weeks to come (from China or HK). I'll see how I get on with the one I got and take it from there.
That's the one I'm getting
https://www.amazon.co.uk/gp/product/B0732NNKGF/ref=ppx_yo_dt_b_asin_title_o00__o00_s00?ie=UTF8&psc=1
EDIT: Cr*p. Only just noticed that it's actually 2A at 5v. Will it still be OK?
audiophilestyle.com/forums/topic/31119-power-supply-8-group-test-lps-and-smps/
I re-did my test again by taping up the 5V & ground contact point on Type A of USB cable and the metal exterior of both ends (type A and type B).I got another powered USB hub with individual power switches. You can switch on and off every single usb input, the lights showing on in which mode is connected UBS device currently, the possibilities being: Off - Charging only - Data or Charging & Data.
If I connect any other dac to the powered hub and switch the corresponding input button on, there is no light on the hub until there is a real signal transmission from the Mac through the usb hub to the dac. When I connect the usb signal out of the D50 to the USB hub, it lights right away, even when the hub is not receiving anything from the Mac. The usb hub is showing clearly that the D50 is drawing power from both the usb signal input and the other usb cable connected to power supply, something other dacs don't do. I have double checked with the SMSL M8a, the M8 and the x-usb II, there is no charging light on the hub when connected, their corresponding inputs start lightning only when the audio digital transmission starts. The D50 on the contrary makes the USB hub lighting right away and all the time. I have also tried to switch off the auto on function, following the logic that there must be some current flowing through the USB input needed for auto powering the dac but even with the auto power switched to off, it was the same.
It is clear that there is no isolation on the USB signal input of the D50, the dac is basically receiving the current at the same time through two separate usb inputs. This might also explain why does the sound using spdif change considerably for better when connected with a single USB cable, the one from the power supply.
D50 does not require 5V or ground on the USB cable to work, it doesn't care about the handshake ground etc. It just needs Data+ and Data-.
It's just that the USB circuit never really powers down completely (drawing power from the external power supply), so it is always detected by the PC.
All power comes from the power supply.
Unplug the power supply, and I believe your hub's light would go off.
Anyway, I may have heard a small difference with the 5V & ground disconnected, but too minor to confirm if it is worth it. If you're using tape, then do it (no cost involved). If you're gonna buy a special cable to disconnect the 5V+gnd... not worth it. Might as well save the money and upgrade the cable or power supply.