Fosi's New Linear Power Supply

[Waveform Fidelity]

negative Sir Fidelity ...
arbitrary random comments like this are useless if based on speculation and false information

to help...I measured it while running and warmed up (15 and 12 V outputs being used at the time )
1) The fan in my PSU20 does not register with a radio shack sound level meter on lowest setting (C weighting 60db range so should see -10db so less than 50 db).
2) using the "Sound Meter" app on my android placed within an inch of the device, then clicked power off ... showed no change. This linear power supply was super quiet near 39 db which matches the basis specs that their specialized fan operates near a lowly 30db (in my case, my normal quiet room was higher)

I do hear (barely) the most quitest of whisper of a fan, only if I place my ear directly on the side of the power supply.
I suspect this fan and cooling will be influenced by your room temp and airflow but to me there is zero issue.
This will be "silent" in all normal situations .
I just checked and turned supply upside for a while and watched fan again ... it isn't moving after half an hour of playing in a 21C deg room

I continue to enjoy the cleaner wiring setup I now have with having one normal plug leaving my desktop area vs 3 power cables to bricks and wallwarts.
My system looks great which was a prime reason/drive in my use case.

My planar Fosi i5 headphones sound great and my near field Totem Loon speakers within 3 feet of my ears is superb (60-90 db listening levels).

Having opened and worked on power supplies in some Dac's like the Fosi R2R BR15 that can manage externally fed DC or direct AC current, and looking at their circuitry, though as good as their components and design are for the money, an external DC linear power source with torriodal power to spare is better step towards clean power from whatever AC source your city has for the Dac's and streamers to do their thing.

Fans make noise and fan bearing wear out so get noisier over time - that’s not speculation but established Engineering fact. The acoustic noise will far outway any electronic noise that gets from your power supply to your your electronic equipement and out through the speaker Get your self a good calibrated microphone and measure you room ambient noise and that of your fan. You will be surprised. And while you are at trying to ridicule my comments go and educate yourself about power supply rejection ration (PSRR)

 

[DonH56]

I had forgotten about this article showing what a "linear" power supply generates...

Power Supply 101 (Linear Supply)

This post (originally from ~2014) introduces the basic operation of a linear power supply, showing voltage and currents at the input and output. There has been a lot of debate about power cords and their impact on the system. Aside from a defective or severely undersized cord I am a skeptic...

www.audiosciencereview.com

 

[Flaesh]

pastel black

I have a light black Ford and shorts that match the car. And light black baffles.
ps: Last seen on avatar.

 

[fpitas]

I had forgotten about this article showing what a "linear" power supply generates...

Power Supply 101 (Linear Supply)

This post (originally from ~2014) introduces the basic operation of a linear power supply, showing voltage and currents at the input and output. There has been a lot of debate about power cords and their impact on the system. Aside from a defective or severely undersized cord I am a skeptic...

www.audiosciencereview.com

Yeah, calling it a "Linear Supply" has to be one of the all-time jokes.

 

[mhardy6647]

Yeah, calling it a "Linear Supply" has to be one of the all-time jokes.

oh, my goodness! Lookee who's here!
Howdy, ol' son.

 

[fpitas]

oh, my goodness! Lookee who's here!
Howdy, ol' son.

Hey! How ya doing?

 

[Keith_W]

Hey! How ya doing?

YOU'RE BACK!!!!

 

[mhardy6647]

Hey! How ya doing?

doin' very well, thank you -- and I hope you are, too.
I should be doin' somethin' far more useful than I am right this minute, though... it is a gorgeous day here; perfect for yard work!
I am imperfect for yard work, unfortunately

 

[fpitas]

YOU'RE BACK!!!!

Lol indeed!

 

[fpitas]

doin' very well, thank you -- and I hope you are, too.
I should be doin' somethin' far more useful than I am right this minute, though... it is a gorgeous day here; perfect for yard work!
I am imperfect for yard work, unfortunately

Yeah, I hate fighting with vegetation.

 

[mhardy6647]

I often tell folks that we torture our gardens.

 

[egellings]

Yeah, calling it a "Linear Supply" has to be one of the all-time jokes.

I think that the term "linear" for the supply is just used to differentiate it from the switch-mode types, despite the nonlinear nature of the silicon diodes used in it.

 

[fpitas]

I think that the term "linear" for the supply is just used to differentiate it from the switch-mode types, despite the nonlinear nature of the silicon diodes used in it.

Sure, it's just a name.

 

[DonH56]

I think that the term "linear" for the supply is just used to differentiate it from the switch-mode types, despite the nonlinear nature of the silicon diodes used in it.

Yes, but it is fed by the whole anti-digital, anti-class D, anti-anything new marketing craze that is misleading at best. Somehow switching at 100/120 Hz is better than switching at 100+ kHz. Just like a turntable and vinyl record somehow recovers more "stuff" than a digital system with hugely greater dynamic range and lower distortion. I love my old gear but don't pretend it is something it is not.

 

[fpitas]

Yes, but it is fed by the whole anti-digital, anti-class D, anti-anything new marketing craze that is misleading at best. Somehow switching at 100/120 Hz is better than switching at 100+ kHz. Just like a turntable and vinyl record somehow recovers more "stuff" than a digital system with hugely greater dynamic range and lower distortion. I love my old gear but don't pretend it is something it is not.

And obviously Fosi knows all about that and moves a lot of "linear" supplies.

 

[egellings]

Yes, but it is fed by the whole anti-digital, anti-class D, anti-anything new marketing craze that is misleading at best. Somehow switching at 100/120 Hz is better than switching at 100+ kHz. Just like a turntable and vinyl record somehow recovers more "stuff" than a digital system with hugely greater dynamic range and lower distortion. I love my old gear but don't pretend it is something it is not.

The 100/120Hz frequency, when rectified by soft recovery diodes, does not spray RF all over the place the way 100kHz switching frequency might.

 

[fpitas]

The 100/120Hz frequency, when rectified by soft recovery diodes, does not spray RF all over the place the way 100kHz switching frequency might.

Schottkys are more likely in 100kHz converters, but in any event, switchers are usually shielded and filtered a lot more stringently.

 

[DonH56]

The 100/120Hz frequency, when rectified by soft recovery diodes, does not spray RF all over the place the way 100kHz switching frequency might.

No, just through the audio band, up to 10+ kHz or so. Plus the transformer introduces noise and leakage at the line fundamental of 50/60 Hz as well; SMPS tend to better isolate the line, and be better shielded to meet all the RFI specs around the world. You can design and shield either type to make coupled and radiated noise a non-issue.

 

[pma]

SMPS may sometimes generate intermodulation products down to the audio band, depending on amplifier design. Usually it is not audible, if the amp design is not very poor.

 

[Mike123]

SMPS may sometimes generate intermodulation products down to the audio band, depending on amplifier design. Usually it is not audible, if the amp design is not very poor.

A LFPS will always generate harmonic distorsion at the most important frequencies of 100-1000 Hz. And they can be heard if the amplifier design is not very good. Those often heard . And they are almost always measured. I couldn't deal with them. Both amplifiers have balanced inputs. LFPS is still noisy.


But SMPS with PFC easily allows you to do this: