Sound Quality Vs. Measurements

[vacuphile]

Originally Posted by Wavebourn

No. SMPS contains rectifier and switches working on high frequency in order to make transformer smaller and lighter. However, as the result they contain much more parts that generate HF, filter, protest, cool down transformers and transistors. If to fit 60 Hz transformers, rectifiers and linear regulators, in the same enclosure with the same cooler, you may get something in the middle in terms of size and weight per power, but of higher quality than SMPS.

It is really beyond me why people believe that transforming voltage at 50 or 60 Hz would be intrinsically better than doing the same at, say, 40KHz. I would argue it is rather the opposite, for one since 50 Hz is quite audible, whereas 40 KHz is not. For another because filtering away 40 Khz spuriae can be done more effectively than getting rid of the nasties created by a linear ps. This on top of the fact that an SMPS can regulate voltage under variable load to within a fraction of a percent. Have any of the steam power adepts ever looked at the rails on a scope, comparing the same amplifier with linear and with switch mode power supplies? It was very revealing to me.

Hence my question to JC, which amplifiers did you modify from SMPS to linear, and it what sense was it an upgrade?

vac

[john curl]

Lower noise.

[a.wayne]

From practical experience, tightly regulated amplifiers tend to sound clamped on dynamics ( when done on output stage) will make a difference over standard steam type if you have poor noisy wall supply ...

[abraxalito]

Originally Posted by vacuphile

It is really beyond me why people believe that transforming voltage at 50 or 60 Hz would be intrinsically better than doing the same at, say, 40KHz.

Its beyond me why beliefs would come into this at all.

I would argue it is rather the opposite, for one since 50 Hz is quite audible, whereas 40 KHz is not.

Whilst 40kHz is not audible directly, its effects can be heard in increased sibilance. I've tried this - switching from a linear bench supply to an amp to a pair of SMPSU bricks without any other changes. I'd really like to use an SMPSU in my amp, but until I know enough about filtering I'll choose linear because it sounds cleaner.

[CopperTop]

Originally Posted by abraxalito

Its beyond me why beliefs would come into this at all.



Whilst 40kHz is not audible directly, its effects can be heard in increased sibilance. I've tried this - switching from a linear bench supply to an amp to a pair of SMPSU bricks without any other changes. I'd really like to use an SMPSU in my amp, but until I know enough about filtering I'll choose linear because it sounds cleaner.

For once, it sounds like something that could be easily measured, to prove that it wasn't just a belief.

[Pano]

But of course not all SMPS are created equal. If you have an amp that allows you to swap power supplies, you might be surprised at how different they sound. Not all of them sound different, but many do.

[abraxalito]

Originally Posted by Pano

But of course not all SMPS are created equal.

Quite so - I forgot to mention I used the cheapest of the cheap SMPSUs - ones without CE/UL approval - but I did add on some extra mains filtering to the inputs.

[CopperTop]

Originally Posted by Pano

But of course not all SMPS are created equal. If you have an amp that allows you to swap power supplies, you might be surprised at how different they sound. Not all of them sound different, but many do.

Well I have read that people are suspicious of the interaction between the audio amp and the SMPS regulation effectively fighting each other - sounds like a reasonable suspicion. It may not be the 40kHz that causes problems, but the regulation by feedback producing spurious output in the audio band. As opposed to 'steam power' that just yields to the demand in a predictable way. But you'd hope it could be measured within the SMPS's output.

[john curl]

Give it a break. Why don't you CRITICS measure switching power supplies, yourself?
I have been around switching power supplies for 45 years. I did a computer ECAP Transient Analysis of one back in 1966, for a military grade switching supply at Friden Calculator. Our custom power supply worked well, too! IF switching supplies were as quiet and as well regulated as linear power supplies, we would use them gladly.
Many mid fi manufacturers use switching supplies because they are cheap, take little space and are efficient, NOT for any other reason, including whether they effect the sound quality or not.

[ThorstenL]

Folks,

Well, a few 100 posts back we had a discussion of what I like to call "hissing sibilants" and most posts where ready to lay blame for them at the feet of the sound- and mastering-engineers that cripple commercial recordings...

Now at my home I am running a system that is a particularly cute mix of the semi-generic and the outrageously extraordinary (and which sounds rather fine to me and visitors) and one thing I particulary noticed was the earlier discussion about spitty, distorted, slurred - whatever you may wish to call them - sibilants is that my system just hasn't got them. The last few days I listened very carefully, even with rather commercial material (I was listening to Johnny Clegg, Israel "Iz" Kamakawiwoʻole and 411 at the time) there is barely ever a hint of this type of sound.

Now I am very familar with this sound and not just from many rooms at HiFi Exhibitions. In the early/mid 90's while taking my 2nd degree (in business information systems and applied alcoholism FWIW) at the UNL I was running at home a system using fairly mainstream equipment (Marantz CDP with DS Converter and Marantz integrated Amp). Well, poor student and all. I was of course tweaking it outrageously.

From day one this "spitty sibilants" stick used to drive me nuts. There where some cuts that did not exhibit it, but mosbunall did.

I eventually tried connecting high impedance headphones directly to the DAC output, after blaming the metal dome tweeters in my speakers (Sony APM-6 which I promptly sold), the Amplifier (which I modified many times), the capacitors in the amplifier (for which I tried all I could conceivably find) and even the wire, also the Op-Amp's in the player and even Marantz's HDAM and spending time and money "fixing them"; only to find that getting it right at best took off a little but the resulting sound had the spittiness remain. Without this bother I might have never really drifted into high end audio and all that, actually.

The direct DAC feed to headphones reduced but not removed this issue, so at the time I figured "it must be the recording" (to a degree it may actually be).

I revised my position when listening with a less conventional system years later to "it is not in the recording in the way it was reproduced then". Since switching to more "unusual" audio systems (I am happy to provide details on application) I rarely observe the spitty or slurred sibilants that others have complained about in this thread (or hi-hats sounding like bursts of air escaping from a tire at that)...

It makes me wonder if my system somehow removes this distortion -

- Unlikely, subjectively it does not seem to remove any sounds, instruments or even detail from the reverbrant tail of instruments and orchestras in concert halls

or offers some amelioration somehow -

- maybe it adds high enough low order distortion to hide or mask the problem, yet most people use speakers with as much low order distortion as my whole system (often more) and keep complaining

or if the "spitty sibilant" problem is one introduced or severely exaggerated in the replay system by interactions between various parts in the system (including the apparent "innocent" use of certain design choices) and the recording?

Ciao T

Now Playing Sheila Chandra - Nada Brahma