Fosi's New Linear Power Supply

[Ruediger]

There are a few people I follow an another forum who constantly 'upgrade' their equipment and report blacker backgrounds with each change. I always imagine that some day, their listening room will get swallowed by a black hole There must be a limit to blackness, no?

If we define this blackness as "nothing" and not as the color, then our journey has just begun.

What is "Nothing"?

Science News, Physics, Science, Philosophy, Philosophy of Science

backreaction.blogspot.com

 

[Ropeburn]

If we define this blackness as "nothing" and not as the color, then our journey has just begun.

What is "Nothing"?

Science News, Physics, Science, Philosophy, Philosophy of Science

backreaction.blogspot.com

Oh no. So if the ultimate blackground has been achieved, and equals nothing, they made nothing out of something? Does the reverse work?

 

[Ruediger]

Oh no. So if the ultimate blackground has been achieved, and equals nothing, they made nothing out of something? Does the reverse work?

I think we will get nothing out of this, so to say.

 

[Ropeburn]

I think we will get nothing out of this, so to say.

And from that nothing, can we make something?

Hardware philosophers aka physicists:

 

[respice finem]

Certainly in this case something can be made out of this "nothing":

Spoiler

money

 

[Sokel]

Absoletely *every* audio company is pandering to these set of custommer in some way if you search for it, even what we would call science/engineering based companies .

Very sciency speaker companies still provides these silly passive biamp terminals for example ? because the dealers want to be able to sell extra cables or even an extra power amp .

Purifi has you covered

They. Are. Business.
All of them. Charity may be the building next to it. Not that one.

Seriously now, even if fosi PSU will never qualify for a "hi-end" setup (lack of heritage, origin, story, etc) , the linear aura (along with the form, desks are not how the used to be, they now are in a constant "photo-ready" state ) will maybe appeal to some.

(hint: a DIY linear supply for such a cost wipes the floor with this one in terms of quality and overspecing)

 

[Redacted]

with the code I posted , one can still get it for 192 USD delivered = 143 pounds = 168 Eur ...delivered to UK... plus any card currency conversion you may have (2.5% is a norm)
...you're welcome...deals are cool.

I agree it still may be pricey vs one's views...but I like the matching box, connectivity and aesthetics vs what I have now.

The so called "key advertised" internals for what they are ..

• 80 W torroidal transformer
• Nippon Chemi-Con Capacitors
• GBU806 rectifier bridge rated at 600V/8A
• three LM1085IT and one ST78M05 linear regulators from Texas Instruments
• some voltage slider switches and included cables blah blah

...googling rudimentarly price for this I add up to 50-100 CAD$ raw (mostly torroidal price variance) . Everyone knows it's much more than the adversised parts to make the power chain cool for audio like the design development, board , and many internals for variable voltage for the prime 2 DC outlets. I will listen in coming weeks after delivery and see if all is still sounding great or at least similar to me . That is the my measure.

Yes the original ZH3 measured very well. I hope this one performs equally great for us Fosi desktop setup owners with a ZH3 and/or ZD3 and a streamer looking for some better looks and flexible features to power our externals neatly



View attachment 542497

I not pedantic about the actual price, I'm just saying it's nit worth more than say, £50.

 

[Beave]

 

[KSTR]

I not pedantic about the actual price, I'm just saying it's nit worth more than say, £50.

Which could be below the absolute minimum viable price, the price the company would need to call without losing money even if the physical core product itself would not cost a single cent to make.

 

[101geo]

The only time I've heard a blacker background was when a power supply went up in smoke so they can make a difference.

 

[AdrianusG]

So again - when the test of a FOSI device shows inaudible noise with the stock power supply - what do you expect to get from a test with this PSU?

I suppose it is useful to prove the linear supply doesn't introduce mains frequency noise that can always be an issue with linear.

Noise that's more "inaudible" than before of course,

wait, now i confused myself

 

[Keith_W]

All this discussion about "black backgrounds" from LPSU's brings me back to the talk I am going to deliver in a couple of weeks to the local audio club. This is my slide about how the noise floor of the listening room affects the listening experience. The noise floor of a "dirty" vs. "clean" PSU is about 100dB below the signal at least. The elephant is literally in the room, and they are ignoring it whilst worrying about miniscule effects.

That talk will be fun. I wonder how many of them will get angry at me or agree with me.

 

[SSS]

All this discussion about "black backgrounds" from LPSU's brings me back to the talk I am going to deliver in a couple of weeks to the local audio club. This is my slide about how the noise floor of the listening room affects the listening experience. The noise floor of a "dirty" vs. "clean" PSU is about 100dB below the signal at least. The elephant is literally in the room, and they are ignoring it whilst worrying about miniscule effects.

View attachment 542623

That talk will be fun. I wonder how many of them will get angry at me or agree with me.

Room noise is an issue but as said masked by the music. With headphones (especially closed ones) room noise is almost not present. And then with a digital zero sound file the residual noise may be heard. Of course I doubt that there is a difference between the power supplies if not one is defect or really bad designed. But I admit that I like the technical best solution. With my measurement instruments I found that linear supplies deliver clean or not so clean DC voltage. And the mains transformer needs to be kept far away from audio cables. Switch mode power supplies do not have much mains harmonics but residuals from its switching frequency which is from 80 kHz up to low MHz. This also can come into audio signal chain but does mostly not create audible effects but can be seen on an oscilloscope. But not to forget that digital audio circuits can have internal switch mode voltage converters for powering.

 

[Sokel]

All this discussion about "black backgrounds" from LPSU's brings me back to the talk I am going to deliver in a couple of weeks to the local audio club. This is my slide about how the noise floor of the listening room affects the listening experience. The noise floor of a "dirty" vs. "clean" PSU is about 100dB below the signal at least. The elephant is literally in the room, and they are ignoring it whilst worrying about miniscule effects.

View attachment 542623

That talk will be fun. I wonder how many of them will get angry at me or agree with me.

Headphones.

Otherwise I agree, a silent room is much nicer .



(I too always think of speakers and people correct me)

 

[Mnyb]

All this discussion about "black backgrounds" from LPSU's brings me back to the talk I am going to deliver in a couple of weeks to the local audio club. This is my slide about how the noise floor of the listening room affects the listening experience. The noise floor of a "dirty" vs. "clean" PSU is about 100dB below the signal at least. The elephant is literally in the room, and they are ignoring it whilst worrying about miniscule effects.

View attachment 542623

That talk will be fun. I wonder how many of them will get angry at me or agree with me.

Is the room spectrum rigth ? it can be better than you think most room noise is in the bass mostly HVAC and traffic rumble ?

There cant be many sources of 1to 3kHz room noise ? where we are at our most sensitive ?

 

[Keith_W]

Is the room spectrum rigth ? it can be better than you think most room noise is in the bass mostly HVAC and traffic rumble ?

There cant be many sources of 1to 3kHz room noise ? where we are at our most sensitive ?

That is an actual measurement of noise in my room. You can do the same, it's quite simple. First, calibrate your mic's SPL. Then use REW's RTA and leave it for about 100 samples. Apply some smoothing, and voila.

I have examined dozens of MDAT's on ASR. In every single one of them, there is more low frequency noise than high treble noise, and this is from rooms from all around the world. This is because rooms act as low-pass filters.

In any case, my point is pretty simple: if you want blacker blacks, tackle room noise first.

 

[mhardy6647]

The only time I've heard a blacker background was when a power supply went up in smoke so they can make a difference.

Ironically, I'll be that the smoke was bluish-grey.


All of these posts about nothing got me to thinking.
There were two outcomes.

1) Quarks. Quarks are clearly the untapped future of the high-end audiophile market.
2) Billy Preston probably put it best.

 

[solderdude]

There are 2 ways in which a power supply can be 'quiet'.

The usual spec is differential and is about the noise/ripple voltage of the actual output voltage.
The other way (which usually is NOT tested for) is between 'ground' and power supply. This is the leakage current.

In the vast majority of cases the issue is NOT the differential noise (so noise/ripple between the power supply) as this is easily filtered inside the device.
This is the spec that is usually quoted as it is easily measured and easy to 'understand'.

If there are any issues it is usually caused by leakage currents (ground loops).
This is rarely ever specified and depending on how 2 devices that are interconnected by RCA or XLR cables the different leakage/common mode currents can actually make it into the audio-path. As soon as this reaches audible levels it becomes a problem as it is not music related and might be constantly present.

If differential noise/ripple voltage is an issue this can usually easily be solved and it points to a poor design (poor PSRR/PSSR).
If leakage/common mode current is an issue it might take a lot of effort to get rid of this.

This means that the differential voltage noise (ripple/noise) is hardly ever a reason to need a 'better' power supply. Yet this is where most people think this is all about.

A 'better' power supply with a very low leakage current may be useful when one is plagued by common mode currents/leakage currents.
Sadly there usually is no specification for this and in a LOT of cases some leakage current is required in order to comply to EMC/FCC rules.

This means in some (rare) cases a 'better' power supply may actually be somewhat useful but this is dependent on quite a few factors.
In all other cases the manufacturer/seller of the power supply totally relies on 'placebo' effects which appears to be the case here.
Preying on the 'audiophool' who wants the best or wants to be 'ensured' the ("all important") power supply is checked.

 

[RScheckmate]

(hint: a DIY linear supply for such a cost wipes the floor with this one in terms of quality and overspecing)

saving perfomance aside until I get one, my main issue is I could NOT find a decent looking 1box solution that handles three DC outputs in the range I need . That is
(1x 12-15v) +(1x12V) +(1x5V )

 

[Mnyb]

Yes that feature ! power 3 devices from one neat looking box instead of a rat nest of wall warts

That’s selling points enough for me , just skip the audiophile marketing. It’s actually a great idea but why stop at 3 ?

There probably no need for a test it will most likely work fine as long as you don’t have special need like precision measurements.