Fascinating. Thanks again!
I recently purchased a DAC bundle that included a Teddy Pardo power supply. Have not tried one previously and was interested to see if I would notice any difference.
The DAC has a standard power supply that can be used for the streamer side only, or both the streamer and analog processor. There is a switch to control the power input if the separate unit is added to the DAC.
I started out listening to hours of music with the standard power supply then added the TP Linear supply. I canât say if there was any difference in the sound but the volume increased considerably. The Dac has a volume control that I turned down 6 db to get it back to the approximate level it had been at. Fairly easy to detect the increase with late night, stay out of trouble, volume setting.
Canât decide if the Linear power supply actually made that difference or if it was the separation of power to the streamer and Dac that did it.
Linear PS cost MUCH more to manufacture which is one reason why companies often prefer switching PS. Switching PS are notoriously noisy and although it can be filtered, the noise can work its way back into your AC mains and to other components. I heard subtle differences when swapping out the switching PS that came with my Nuc+ to a beefy, heavily regulated, linear PS (Keces P8). If the rest of your system is optimized, you might consider replacing a switching PS with a linear PS to see if you can hear a difference yourself?
1 Like
They cost more not least because thereâs a pound of iron, and 2 pounds of copper in each transformer.
Iâve heard linear psuâs hum, but never a switch mode psu switch, ever! A bad design is a bad design, irrespective of mode. Not all smps are bad.
Linear PSUs often use toroidal transformers to reduce magnetic field induction in nearby components (reduce hum). However they are prone to DC on the incoming mains and will respond to this with a pronounced mechanical hum.
SMPS can sometimes be heard as a high frequency hiss, but most modern ones operate at very high switching frequencies, well above audible frequencies. Sub harmonic oscillations can occur though, and these can be within the audio band, especially annoying if they vary in frequency with load.
2 Likes
Doesnât stop me from being able to hear the âelectronic transformerâ used to drive my kitchen worktop lighting. It is very quiet though, but at my age Iâd be surprised if my hearing got anywhere near 15kHz.
I have a DC filter on the power supply to my amp. Without it the toroids buzz very loudly from time to time.
Yes, you have missed something. A linear power supply is a normal PSU, at least regarding what is normally built into audio equipment. If a piece of electronic equipment does not have a built in power supply, typically it will be a âwall wartâ type. These are usually switch mode power supplies, but not necessarily. In either case they are typically not high quality power supplies, in terms of regulation and noise isolation. Your choice of an alternative external power supply shouldnât be just whether it is linear or switching. Itâs possible to design and build a high quality switching supply (those used in David Berning equipment come to mind) or a crappy linear supply. A switching supply is indisputably more efficient, but care needs to be taken with shielding and isolation. Pitfalls in linear power supply design include âmore is betterâ filter cap philosophy resulting in excessive transformer heating, and improper regulator margin (if regulated); too small results in crappy regulation, too large in inefficiency and excessive device heating to the detriment of its reliability.
@Leporello this is a very good point. I once sold a very high quality medical grade switching supply from Japan it had lower noise on the output then many linear supplies. The only problem is it cost $800.
I now sell a very low noise linear supply for under $300. I think it easier to make a low noise linear supply then it is to make a low noise switcher.
So if you are looking for a supply that will make your audio equipment sound better it doesnât matter what type it is just make sure itâs from a manufacture that has a reputation for making good low noise supplies.
1 Like
I hesitate to open this can of worms, but the only data one could possibly present as to whether or not something is audible is from a large panelâthe larger the betterâof listeners doing blind comparison, unaware of which item under test is which, and get a statistically significant result. You personally may hear a difference, but thatâs not going to convince anyone who doesnât that there are audible differences. Conversely you can do THD, IMD, TIM, spectrum analyzer, waterfall, etc. measurements and get identical results, but that doesnât prove there arenât audible differences that your measurements donât capture. A classic example is amplifiers in the 60âs and 70âs designed by engineers trained in feedback theory who should know better, all measuring triple aught one distortion, achieved by massive amounts of feedback, some of which turned out to have gross transient intermodulation distortion.
Debates will always rage among audiophiles as to the validity of blind testing, some arguing that getting the ârightâ results is a quantum mechanical impossibility, like determining through which slit in a diffraction grating an individual photon passes. But the fact remains the only scientific way of determining audibility that I know of is by such methodology. Otherwise itâs like the Firesign Theater schtick I keep quoting:âHow can I know what you hearâ?
3 Likes
Some interesting observations.
I always wonderâŚif a linear power supply is immediately followed by a switch mode power supply in the device being powered, does it really matter? In what ways? Feel free to get technical.
Blind testing is an activity that everyone talks about and no one actually does. It seems to be quite the opposite of another human activity that everyone does but no one talks about. Unlike blind testing, this other activity is very enjoyable, healthy, and FUN!
Happy listening all.
Tom
1 Like
Hmm, so you already have DC at this point plus the option to tap another voltage at the LPS to feed different power rails. Why would you?
Thatâs the way most DACâs having the option for a DC input are designed. The DC input goes right into a series of switch mode power supplies; +3.3 V for the digital side and +/- 5 to 12 Vdc for the analog section. So your quiet DC supply is driving a switcher anyway. This is also true for most other devices like NUCâs and Ethernet switches having a DC input. Iâm sure that there are exceptions but they would be rare.
It doesnât make sense to connect one AC to DC power supply to another. However, there is such a thing as a switch mode regulator. This would be the worst of both worlds. You would still presumably have a transformer operating at 60hz (or whatever your mains frequency is where you live), with its inherently higher leakage inductance and core loss=lower efficiency and more heat generation, and you would also have high frequency, high harmonic content noise that has to be carefully shielded and filtered for high performance audio applications.
Many blind tests have been conducted and some have actually been talked aboutâand their methodologies hotly debated. By bringing up the topic I merely meant to point out that when someone says âshow me the data that indicates this makes an audible differenceâ, that is the only route I know of. If you just gathered together a few people and said "here is a Raspberry Pi with Hi Fi Berry HAT with a stock wall wartâŚnow here it is with an expensive Hi End Certified linear power supply, and everybody said âOh, yes, I can clearly hear the differenceâ, it wouldnât prove much of anything. Bias would be fundamentally impossible to avoid.
I have no idea what activity nobody talks about but everyone does and enjoys you mean. Music listening and sex are both widely talked about.
I have a MCRU linear power supply for my Mytek Brooklyn DAC and the custom built VOLT power supply for the Stack Audio Link II streamer, and I think they definitely add improvements to the sound, especially the VOLT. imo this forum has the best hifi knowledge on the web so I wonder if I could take the subject slightly off topic and not talk about streamed music and ask about LPS for a CD transport that I have.Could anybody recommend an LPS that would be compatible with a Pro-ject cd box ds2 t? The power spec is 9v and 2a for this player. I donât ever recall seeing much chat over LPS for CD players, is this even a thing?
The thing that puzzles me is would any âaudioâ LPS that handled 9v do the trick? I often see brands advertising their LPS to be used with specific streamers and DACs, so are these LPSâs custom made for these streamers and DACs, or are the LPS companies just hitching on the name of the hifi brands when they could actually be used with any streamer or DAC?
I hate to say it, but everything has probably already been covered, and you should probably just draw your own conclusions.
9 volts @ 1 amp is 9 volts @ 1 amp, irrespective of circuit topography. Your equipment should demand far less than the supply is able to provide at max.
1 Like
^ demand less current (amps), the voltage (volts) needs to match requirement, eg, 9 volts.
So does anybody use an LPS with a CD player, or is it not a thing?
Some people put them on anything they can though I would imagine most CD players have internal power supplies.
1 Like
Yes I guess they do, but isnât the whole thing about LPS that they are better quality than the power supplies they replace on hifi equipment? Itâs weird though, on any hifi message board you care to mention there is chat about LPS for streamers and DACâs but not for CD players and Iâm just curious as to why that is?