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For many years I've seen posts on the Slimdevices forum and elsewhere where users claimed sonic benefits from powering their SB3's/SBT's/RPi's etc. acting as transports/DACs with linear PSU's rather than the supplied wall wart SMPS units. Since switching from LMS to Roon and swapping out a SB Touch for an ODROID C2 SOC as transport my interest was again piqued as it was similarly claimed that there's a sonic benefit from separating the server / database engine/ DSP/ UI etc. from the transport end of the equation. I'd also encountered many posts here and elsewhere where it was argued that powering a DAC's USB input using a supply external to that of the incoming USB cable (of course only of relevance where a DAC's USB input is expecting power to be supplied via the incoming USB cable) similarly yielded sonic benefits.
I've always been on the skeptic side of this argument but decided to it was time to test and ascertain whether or not it bought about any sonic improvements for me. I obtained USB pigtails that enable external power supply and two very, very good LPSU's.
I then went about sighted testing of various combinations:
(1) SMPS powered ODROID > USB > DAC
(2) SMPS powered ODROID + LPSU > USB pigtail > DAC
(3) LPSU powered ODROID > USB > DAC
(4) LPSU powered ODROID + LPSU > USB pigtail > DAC
As my Hi-Fi has been packed up ready to move and I no longer have two Vivere DACs I was reduced to doing this testing using Sennheiser HD800's and my Jotunheim HPA with some inline 12-step attenuators to volume level the Joty's SE and balanced inputs.
I struggled to conclusively ascertain whether or not there was any tangible difference between (1) and (2), perhaps (2) had it.
I struggled to conclusively ascertain whether or not there was any tangible difference between (3) and (4), perhaps (4) had it.
Both (3) and (4) yielded what seemed to me to be obvious improvements over (1) and (2).
Self doubt set in...having splashed on the LPSU's was I hearing what I needed to hear despite my initial skepticism? I didn't want to hear any differences damnit. I needed to try this with a really good set of speakers.
I spent the afternoon at Ian's place listening to his latest masterpiece. Later in the day I used to opportunity to try (1), (3) and (4). I said nothing about what I was expecting to hear.
Conclusion, there's an unmistakable and obvious sonic benefit in (3) and perhaps a tiny, incremental benefit in (4). If you're using RPi etc. as transport to your DAC you'll benefit from using a good LPSU to power the transport.
I've always been on the skeptic side of this argument but decided to it was time to test and ascertain whether or not it bought about any sonic improvements for me. I obtained USB pigtails that enable external power supply and two very, very good LPSU's.
I then went about sighted testing of various combinations:
(1) SMPS powered ODROID > USB > DAC
(2) SMPS powered ODROID + LPSU > USB pigtail > DAC
(3) LPSU powered ODROID > USB > DAC
(4) LPSU powered ODROID + LPSU > USB pigtail > DAC
As my Hi-Fi has been packed up ready to move and I no longer have two Vivere DACs I was reduced to doing this testing using Sennheiser HD800's and my Jotunheim HPA with some inline 12-step attenuators to volume level the Joty's SE and balanced inputs.
I struggled to conclusively ascertain whether or not there was any tangible difference between (1) and (2), perhaps (2) had it.
I struggled to conclusively ascertain whether or not there was any tangible difference between (3) and (4), perhaps (4) had it.
Both (3) and (4) yielded what seemed to me to be obvious improvements over (1) and (2).
Self doubt set in...having splashed on the LPSU's was I hearing what I needed to hear despite my initial skepticism? I didn't want to hear any differences damnit. I needed to try this with a really good set of speakers.
I spent the afternoon at Ian's place listening to his latest masterpiece. Later in the day I used to opportunity to try (1), (3) and (4). I said nothing about what I was expecting to hear.
Conclusion, there's an unmistakable and obvious sonic benefit in (3) and perhaps a tiny, incremental benefit in (4). If you're using RPi etc. as transport to your DAC you'll benefit from using a good LPSU to power the transport.
