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Linear Power Supplies - any improvement in sound?

PostPosted: 09 Jan 2015, 11:29
by LC1
Hi,

I was wondering what people's thoughts were on this? Would a linear psu, such as a relatively inexpensive one from Strontronics for example, yield any noticeable improvements in sound quality over a standard switching wallwart for powering a Pi B+ and i2s DAC board?

Anybody using any inexpensive linear supplies that they would recommend?

Cheers,
Luke

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 29 Jan 2015, 19:38
by phalanger
I have not yet tried this myself (but plan to, soon), but normally yes this should yield a noticable improvement in sound. Especially DACs perform better with a good regulated power supply.
I'm not familiar with Strontronic products.

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 01 Feb 2015, 10:09
by ABBDVD
I wonder if an EMI (electro magnetic interference) filter can be used instead of an improvement by linear power supply or if it helps even in combination.

To clarify all 4 'options' I see:
  • USB charger -> RPi
  • (1) EMI filter -> USB charger -> RPi
  • linear power supply -> RPi
  • (2)EMI filter -> linear power supply -> RPi
Is (1) as good as (2)?

I guess that might depend a lot on how good the USB charger is too.

I am running currently (1). I bought a schaffner IEC filter, placed it in a small box with a cable towards a 'regular' female plug for the USB charger.

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 08 Feb 2015, 21:34
by phalanger
EMI filter helps to reduce interference from the AC line (and vice versa), but does not otherwise improve regulation of the DC signal. A transformer and a rectifier+regulator would provide a better power source than a wall-charger. How much audible improvement it would give is hard to say and will depend a lot on the rest of your system.

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 09 Feb 2015, 13:39
by dwijtsma
Building a 'good' SMPS isn't easy. Most suppliers fail at this, so don't buy a cheap SMPS. EMI filters won't make it any better. If you use a I2S dac. Just power it from a non switching, a bit over dimensioned power supply. It's not very expensive and it won't get much better than that. Every person with an electronics degree is able to design such a circuit and routing the PCB isn't very critical.
I think other electrical engineers will also agree on this also.
Good luck with it!

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 16 Feb 2015, 12:34
by LC1
Thanks for the interesting replies. I haven't actually been able to find a linear power supply for the Pi at reasonable cost, and considering that the consensus seems to be that results will be minimal I probably won't bother with this now...

(unless anyone else thinks that they have had great results doing this, that is?!)

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 29 Apr 2015, 13:54
by sawesi
The Best Power Supply is a battery or accu.
DIY with some inexpensive battery holders for the 5,2 Volts required.

This should be the best PS, and all others can be compared by listening for a week or so.

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 29 Apr 2015, 17:19
by Aquarius
sawesi wrote:The Best Power Supply is a battery or accu.
DIY with some inexpensive battery holders for the 5,2 Volts required.

This should be the best PS, and all others can be compared by listening for a week or so.

This!
With a little tinkering with the GPIOs in the Pi and relays in the charging circuit, you should be able to setup a script that:
- Sest the battery in "charge" mode when no music is playing (when clicking on "Stop", when at the end of a playlist, ...)
- Isolates the battery from the charging circuit when playing something. (clicking on "play", when "add and play" music directories or files, etc....)

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 01 May 2015, 16:18
by ACX
sawesi wrote:The Best Power Supply is a battery or accu.

In my personal experience, a good quality linear PSU always outperformed the battery, which produces a sound that is clean but usually lacks of energy and liveness.

Re: Linear Power Supplies - any improvement in sound?

PostPosted: 22 Jun 2015, 23:43
by Discovery
I received an ultra linear power supply from Tomanek in Poland (http://www.tomanek.net.pl) today (I'm in England). I bought one of his ULPS Mini units, fitted with the correct plug for the Pi.

The cost was 300 PLN. The build quality is very good and the sound is noticeably better.

My system consists of the Pi 2 running Rune, mostly sourcing FLAC files from NAS or USB. I run this through an Audiolab MDAC, out to a Quad 909 power amp and then into Quad 989 electrostatic speakers. The Pi is definitely living comfortably in this company. I'm very pleased.