Any idea about a +5VDC very low noise psu that could be used with a dac ?

[gino1961]

The question is if you experience any noise coming from the USB bus powering at all.
If you can not hear any noise/interference at all, why bother with a separate PSU?
There are some topics about power supplies and measurements. My understanding is that there can be measurable differences but all outside of the audible range.
Personally I did invest in a good USB power source for my DAC, I use a Apple USB phone charger vs a generic one

Thanks ! i am sure Apple charger could be an improvement over the standard no brand charger ... and also brand charger
I am attaching what i am using now.
https://www.ebay.com/itm/TeraDak-U9...ction-Hi-Fi-Linear-Power-Supply-/183674253919

 

[gino1961]

Ah, that changes the issue a bit. However, note that a clean PC power supply is no guarantee either. The PSU might not have been the source of the noise in the first place. It could be one of the numerous switching regulators on modern mainboards or just plain bad layouting.

I must apologize because I understand now that I have made a mess. Unfortunately English is only my fourth language (bad joke ... I can only say one thing OT ... if it had been the first life would have been much easier. I need it badly for my oil & gas job ).
Anyway ... i was looking for a small/cheap dac for my tv that has, like all TVs, a digital optical out. So i bought this little dac and was amazed at how it sounds. Clearly the appetite comes with eating and I'm wondering to what extent it can sound good with a higher quality power supply than the usual usb charger. I'm curious.
Speaking instead of pc music for me the solution with the pc is a usb to spdif interface and then the dac. I am sure that the very best dacs work well even directly connected to the PC but I already have the interface and it is not bad. At opresent I do not use much the PC as in the past because I am still busy from work. I should be retiring in months. And then the party begins. With little money unfortunately.

Did the OP try powering the thing via the AUX already (with a phone charger)?

Yes is what i am doing because i use the optical connection with my TV mainly for Youtube and Netflix. I have noticed for instance that if the system is decent the sound effects in Netflix movies can be very realistic.
Differently from other people think i prefer bad recordings on high quality system
This is a good reason for me to want to improve the system.
And i have another long term obsession ... the giant killer. When a cheap unit performs much above its price. And my guess is tha this little dac from SMSL is one case. I am sure i am not listening it at its full potential.

 

[solderdude]

sounds like it is not a power quality issue but groundloop.
Changing the power supply will not help.
Use a powerbank and when there still is a hum you have a groundloop.

 

[gino1961]

sounds like it is not a power quality issue but groundloop. Changing the power supply will not help. Use a powerbank and when there still is a hum you have a groundloop

Hi ! i tried and i can say that there is a very very low noise that i can hear if i put the ear some cm from the woofer on the speakers.
Then i switched off the dac and the noise more or less is the same. So my guess is that is the noise floor of the power amp. I know i should shortcircuit its inputs to be sure that it does not catch external noise. But it is very very low.
With the dac powered by the USB power supply the noise is slightly higher that when using the power bank.
I think i could use a power bank then for critical listening ... if the unit draws 300mA a 20,000mAh power bank could power the dac for 66 hours ?
it is a lot indeed. A 27 euro power bank could be the solution ? ...

 

[abdo123]

Hi ! i tried and i can say that there is a very very low noise that i can hear if i put the ear some cm from the woofer on the speakers.
Then i switched off the dac and the noise more or less is the same. So my guess is that is the noise floor of the power amp. I know i should shortcircuit its inputs to be sure that it does not catch external noise. But it is very very low.
With the dac powered by the USB power supply the noise is slightly higher that when using the power bank.
I think i could use a power bank then for critical listening ... if the unit draws 300mA a 20,000mAh power bank could power the dac for 66 hours ?
it is a lot indeed. A 27 euro power bank could be the solution ? ...

Do you hear the noise from where you sit?

 

[Iglo]

Thanks ! i am sure Apple charger could be an improvement over the standard no brand charger ... and also brand charger
I am attaching what i am using now.
https://www.ebay.com/itm/TeraDak-U9...ction-Hi-Fi-Linear-Power-Supply-/183674253919

It was a bit of a joke although with a serious note. Generic chargers can vary greatly in quality (and safety). Apple chargers, as you would expect, do perform very well and are quite advanced especially compared to some fake/unbranded chargers. But as mentioned I do not expect much benefit over a cheap but good USB phone charger vs something more specialized.

 

[gino1961]

Do you hear the noise from where you sit?

absolutely no ... no way to hear it Only if i put the ear at 5cm from the woofer. It seems more on the woofer than on the tweeter.
Unfortunately i do no have an audio analyzer. I think that people who spent thousand and thousand on equipment should run some measurements when setting up their very expensive system. To optimize it. Noise is a beast ... the lowest the best. When the overall noise floor is very low i am sure the details jump out more easily. I am sure of that. Thanks a lot again for the very kind and valuable advice.
Now i am already looking for noise measurements on power banks. I have found that depending on the power draw it can go from 20mV to about 100mV RMS. The Shanti psu trounches them all

... This intelligent design allows a noise level of 80nV (0.08µV on the 0Hz-20kHz frequency band) ...

with that the psu issue would be definitely closed.

 

[solderdude]

Hi ! i tried and i can say that there is a very very low noise that i can hear if i put the ear some cm from the woofer on the speakers.
Then i switched off the dac and the noise more or less is the same. So my guess is that is the noise floor of the power amp. I know i should shortcircuit its inputs to be sure that it does not catch external noise. But it is very very low.
With the dac powered by the USB power supply the noise is slightly higher that when using the power bank.
I think i could use a power bank then for critical listening ... if the unit draws 300mA a 20,000mAh power bank could power the dac for 66 hours ?
it is a lot indeed. A 27 euro power bank could be the solution ? ...

Using the powerbank is only to see if the power supply would be introducing noise. Powerbanks are also switching power supplies but they cannot have a groundloop. So the powerbank is not a solution to a problem but merely a test.
When it is just noise it does not come from the power supply.

 

[Matias]

Hi ! i am playing with the SMSL Sanskrit 10th dac that i like a lot.
I have the feeling that it can sound better when powered with a dedicate psu instead of relying on usb bus power even if it is enough for the job (i think the dac needs 300mA at 5V ?)
There are other very high quality dac using this low voltage.
I would like to ask some suggestion about a decent DIY solution instead of shelling out big money for some exotic option.
I have seen high end psus going for almost 500 USD. I do not discuss their quality of course ... but while they can have a reason for powering a 2000 USD dac they are hardly reasonable for a 100 USD dac.
Any suggestion would be very welcome and appreciated.
Kind regards,
gino

Get an iFi iPower for 50 usd and you are set. Very low noise, price is reasonable.

https://ifi-audio.com/products/ipower/

 

[Bullwinkle J Moose]

Ah, that changes the issue a bit. However, note that a clean PC power supply is no guarantee either. The PSU might not have been the source of the noise in the first place. It could be one of the numerous switching regulators on modern mainboards or just plain bad layouting.

Did the OP try powering the thing via the AUX already (with a phone charger)?

Testing my DAC's with the worst computer power supply on the planet "IS" relevant to this discussion and the noise is not coming from the motherboard as it vanishes once a decent power supply is connected

Using a USB connection instead of optical is the worst case scenario for testing noise rejection

If you speakers and amp are turned all the way up (or just until you hear noise coming from the amps), then any additional noise is from the DAC's imperfect noise rejection capabilities when you connect it and play a silent WAV file (all digital zero's)

Many DAC's do not actually output a signal + noise unless the wav file has at least some audio content to "turn it on" so to speak

I add a tiny tone to the beginning of the wav file to turn on all DAC's under test and then listen for any additional noise at maximum volume

With a 10 foot USB cable and the noisiest power supply I've ever heard, I don't get any additional noise from the SMSL DAC itself (that can be heard) and it rejects the noise coming from the USB input (not optical) in addition to the ground plane and power supply

Lesser DAC's, add various amounts of noise that can be heard (even with an optical input)
( Try the Micca origin G2 with this test and see what happens - LoL )

Testing on the USB line, with the longest USB cable that still works, and with the noisiest power supply is a valid test to see if the DAC can reject all of it and still pass a clean audio signal

THIS WORKS!

Some lesser DAC's do not reject audible noise from the power, and some add noise of their own creation, like the Fiio D3

The SMSL does not add any additonal audible noise of it's own and rejects all audible power supply noise in a worst case scenario

Win / Win

To sum this up.....
With a great DAC, it doesn't matter if you have a noisy power supply because the DAC filters it (in many cases) as well as a good power supply can filter it

 

[abdo123]

If you can’t hear the noise where you sit then there won’t be an improvement.

 

[gino1961]

Testing my DAC's with the worst computer power supply on the planet "IS" relevant to this discussion and the noise is not coming from the motherboard as it vanishes once a decent power supply is connected
Using a USB connection instead of optical is the worst case scenario for testing noise rejection ... With a 10 foot USB cable and the noisiest power supply I've ever heard, I don't get any additional noise from the SMSL DAC itself (that can be heard) and it rejects the noise coming from the USB input (not optical) in addition to the ground plane and power supply ...

Hi ! very interesting indeed. I miss your SMSL dac model ... i have a Sanskrit 10th mk II This is the very entry level model
It is very likely that better/pricier dac have also a better psu noise rejection ... i am using only my ears put against the speakers
Very trivial but i think effective way to test ...

Lesser DAC's, add various amounts of noise that can be heard (even with an optical input) ( Try the Micca origin G2 with this test and see what happens - LoL )
Testing on the USB line, with the longest USB cable that still works, and with the noisiest power supply is a valid test to see if the DAC can reject all of it and still pass a clean audio signal
THIS WORKS!

Some lesser DAC's do not reject audible noise from the power, and some add noise of their own creation, like the Fiio D3
The SMSL does not add any additonal audible noise of it's own and rejects all audible power supply noise in a worst case scenario
Win / Win

which model do you mean ? there are many SMSL dacs at quite different price points The best ones are really beautiful ... but i am always looking for the next giant killers ... the David dac ...
I remember years ago a story of a little dac from Art
https://www.usaudiomart.com/details...ler-dacs-when-modded-correctly/images/878482/
with an upgraded psu and some mods i think it won the best sound of the show at a CES years ago of course with a cd transport from Krell and very high quality amp and speakers. But this means to me that it was not a weak link. I have a rule ... if a playback chain sound very very good indeed also the element of the chain must be very very good

To sum this up.....
With a great DAC, it doesn't matter if you have a noisy power supply because the DAC filters it (in many cases) as well as a good power supply can filter it

And this is completely fine. Problem is to understand the price of admission to a great dac ...
I would have bough the above mentioned Art dac but there are two issues:
1) i would like an optical input while the Art has only coaxial spdif in and out
2) i am quite sure that it is very sensitive to jitter ... and actually it needed a very high quality cd transport to sound the best Like the Krell MD-10 i think it was the one used at the show.

In the meantime i have something about psu noise in the web ,,,,

OK, we threw the Teradak PSU on the scope today ...(not sure it was mine model by the way)
.... we did have an apple 5V USB power supply and a generic 5V USB power supply.
The generic power supply revealed around 250-300mV of noise under no load, and an increase over this figure when under load.
The Apple power supply revealed around 80mV of noise under no load, and an increase over this figure when under load.
The Teradak linear PSU showed 2mV of noise... but unfortunately this was the limit of our testing, as there was 2mV of noise with nothing connected to the scope ...

In my psu i have two outs ... one usb and the other the usual dc socket. I understand that the output V on the dc socket is variable (there is a trimmer inside)
I have ordered some precision screwdrivers and will try the dc socke out I really hate micro usb connections.
By curiosity i searched for standard DC plug types ... and found this

IEC 60130-10:1971 defines five DC power connectors.
Type A: 5.5 mm OD, 2.1 mm ID (with optional screw lock)
Type A: 5.5 mm OD, 2.5 mm ID (with optional screw lock)
Type B: 6.0 mm OD, 2.1 mm ID.
Type B: 6.0 mm OD, 2.5 mm ID.
Type C: 3.8 mm OD, 1.1 mm ID.
Type D: 6.3 mm OD, 3.1 mm ID
Type E: 3.4 mm OD, 1.3 mm ID.

As usual what i think is the best by far ( i.e. Type D: 6.3 mm OD, 3.1 mm ID) is almost never used.
Its bigger size allows for a wider contact area and that is a very good thing to have.
Actually i have another very old dac the Cambridge Audio Dacmagic 100 that has this type. I lost the power supply and now i am getting mad to find a replacement because it is very unpopular let's say. If i had the power i would make all the other standards illegal. Only Type D for All !
And life would be much better and simpler
signed ... the ranting boy

 

[gino1961]

If you can’t hear the noise where you sit then there won’t be an improvement

Yes and thanks. I know it is a very trivial test ... but i am noticing that putting the ear very very close to the drivers provides a good idea of the overall noise floor. I have some noise ... not exaggerated but there is noise.
And i am afraid even with just the power amp connected i have already noise. I have to try shorting it inputs. I will do asap. I would love to have a very low noise floor chain. Once i watched a video where the man was comparing the noise floor to a carpet ... high noise = long pile carpet low noise =short pile carpet
If you drop very small object on a long pile carpet you cannot see them Instead on a very short pile carpet you can still see them
This is one reason why a very low noise floor is a good thing ... i can listen to the smallest sonic details
If the amp will still be noisy after shorting its inputs i am thinking about replacing it. I have seen even vintage power amps with S/N ration of 120dB Unbelievable. One being for instance this one ...
https://www.hifiengine.com/manual_library/kenwood/basic-m1.shtml

To end the ramblings ... i am pretty sure that at some point i will be buying the Shanti. It is really a spectacular unit that justifies absolutely its price.
But ... i will be modifying it anyway. I just cannot tolerate captive power cords in general. I am for liberty ... i hope to be able to make two holes in the back plate and put some really nice sockets on it. I really do not understand why they have not done that from the beginning.
Anyway the noise spectra are too good to be true.

 

[Bullwinkle J Moose]

Unfortunately i do no have an audio analyzer. I think that people who spent thousand and thousand on equipment should run some measurements when setting up their very expensive system. To optimize it. Noise is a beast ... the lowest the best. When the overall noise floor is very low i am sure the details jump out more easily. I am sure of that.

There is a very simple test for most people who have a decent digital audio recorder and a computer

I have one digital recorder that has a noise floor @ -74 dB regardless of where the input volume is set, and the noise floor cannot be heard even with the output volume at maximum on the specific headphones I use

This means that any audio output from a DAC with a lower noise floor than the recorder cannot be heard or measured

I then record output samples of SILENCE into the recorder from every piece of audio gear I use

Any noise floor above -74 dB is recorded for some very specific reasons

1. To compare the relative noise floors of any components above -74dB

2. To SEE as well as hear what type of noise I CAN record by normalizing the volume of the noise floor to -3dB in a software audio editor on a computer

By boosting the volume in an editor, this let's me hear what the noise floor sounds like (or the type of noise it generates)
Some of my older components have 60hz transformer hum over noise
Some, like the Fiio D3 DAC add a spiked clock signal over the noise
and some are generally just a basic white noise sound

3. To keep a master list of every component with a noise floor so low that it cannot be recorded or heard
THESE are the components to use when recording or listening!

If you cannot record it, or measure it, or hear it even at maximum volume, then it basically does not exit for all intents and purposes

 

[Katji]

Ah, that changes the issue a bit. However, note that a clean PC power supply is no guarantee either. The PSU might not have been the source of the noise in the first place. It could be one of the numerous switching regulators on modern mainboards or just plain bad layouting.

[I deleted the last sentence I wrote, thought I was going too far.] Yes, so start there with the stories about special "audiophile computers" with expensive linear PSU. I saw one a few days ago, a computer build list, the PSU was like >500 euros. Although someone else [on that forum] has many times pointed out that there are so many high-speed devices making noise. ............................And then we go back to rationalising the need for USB decrappifiers.

 

[gino1961]

There is a very simple test for most people who have a decent digital audio recorder and a computer
I have one digital recorder that has a noise floor @ -74 dB regardless of where the input volume is set, and the noise floor cannot be heard even with the output volume at maximum on the specific headphones I use
This means that any audio output from a DAC with a lower noise floor than the recorder cannot be heard or measured ...

Thanks a lot for the very interesting idea. I will try to do the same asap. I already have this one
https://www.amazon.com/Tascam-DR-70...keywords=Tascam+DR-710&qid=1617459722&sr=8-15
i bought it 2nd hand but never used ... unfortunately the inputs are xlrs ... i do not know if a rca to xlr adapter will work fine I have to try
I have to get back from another location ... i will be retiring soon I will have much more time then
I like when the music emerges from a completely black background ... as the reviewers often say

 

[gino1961]

Ok i checked and the origin of noise is indeed the power amp ... not much of course but still it is humming a bit
I really do not know if it is due to a ground loop or what but ... maybe it is a too little capacitance ? i will peep inside again
Last time i did i saw marks on the board for another couple of psu caps.
And switching on and off the dac does not change the noise i get from the speakers. I am surprised. I started from the assumption that the amps are usually dead silent. Clearly it is not the case here.
I was putting the blame wrongly on the nice little dac ... i am sorry Sanskrith

 

[Katji]

ok, now to fix the problem of the amplifier ground loop. (Something which never happened with me, I hope it continues like that.)

By the way, you will have more time, but maybe not like you think. ...You will see.
4th language, seriously? ...I have only 1.5. But maybe I will have to begin learning another.

 

[Bullwinkle J Moose]

Thanks a lot for the very interesting idea. I will try to do the same asap. I already have this one
https://www.amazon.com/Tascam-DR-70...keywords=Tascam+DR-710&qid=1617459722&sr=8-15

The test is relative to the precedure

When I say -74dB noise floor, you should not read too much into that

The manual for a my Tascam DR60D-Mk2 recorder shows a much lower noise floor, but the level I get is relative to my testing procedure yet valid for testing even though it may seem quite high

and I used the 3.5mm input (not balanced)

 

[gino1961]

ok, now to fix the problem of the amplifier ground loop. (Something which never happened with me, I hope it continues like that.) By the way, you will have more time, but maybe not like you think. ...You will see.

Hi again ! i am sure of that ... audio is for me a life long interest ... if i had been good at math i would be designing hifi ... i am sure of that
At school i was decent only with instruments at lab ... i studied chemistry because it is mainly a matter or having decent memory ...
Just to tell you one thing i had never touched a test tube before university ... and actually at the first lab i broke some of them ...
But then something happened ... i fell in love with instruments ... i ended the course with the same top marks of a friend who is now professor at the university every time I meet him he tells me ... " I can't understand how an idiot like you got the same grade in the laboratory as myself" ... and he says it a little pissed off ... and I laugh He is very very good at the point that i take his insults as compliments

4th language, seriously? ...I have only 1.5. But maybe I will have to begin learning another

nnnnoooo ... don't do that ... we have to simplify the world ... i would be very willing to accept the imposition of english as world language
I work in a oil & gas company ... we have to use both italian and english language. I find english language much much better to write manuals and operating instructions. Much better. I think this is due to the much more pragmatic mindset of anglosaxons. Italian is more for poems and opera maybe ... even if also the english language sounds quite good indeed. But italian ... at least in some cases like this one

by the way ... I can't explain how annoying I find the applause at the beginning of the song. There is plenty of time after the end to peel your hands ... isn't it ?