[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
jhm731;175585 Wrote: As I predicted in your part 1, I didn't think youd hear any difference with this cheap linear PSU. Well, of course! Any solution to an audiophile problem that doesn't cost at least a grand can't possibly be worthwhile :) (runs for cover) -- ceejay ceejay's Profile: http://forums.slimdevices.com/member.php?userid=148 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175687 Wrote: Many on this forum and others have reported huge improvements from using linear PSU's at the same price point and below (this one sells for as much as $30, evidently). Furthermore it was opened up and checked, and it's perfectly well constructed. You just have to believe... I'll try that again later :-). By the way, to any of those that hear an improvement - do you hear a lower noise floor with the linear PSU? That is, max the volume on your amp, put your ear next to the tweeter, and compare that to the stock PS. You might also try playing a silent track (which you can generate in several ways, or I can attach one here). If there's no difference in the noise floor, which is the case for me, why would the PS matter? Any differences should be much more easily audible when they aren't masked by music. What is the rest of your system? In my system I strongly suspect my TacT didn't like the SB's wall wart. The symptom was a loss of imaging and a more fatiguing sound in general. Re. display noise: You wouldn't expect that to change depending on extrenal power supply. -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
P Floding;175700 Wrote: What is the rest of your system? In my system I strongly suspect my TacT didn't like the SB's wall wart. The symptom was a loss of imaging and a more fatiguing sound in general. Re. display noise: You wouldn't expect that to change depending on extrenal power supply. SB3 - custom Odyssey Audio Cyclops - BW CM4 (which are pretty good floorstanding box speakers with very high MAF/WAF). I wasn't referring to the display noise (although I see no reason why the PS would be less likely to affect that than music). I was referring to the overall noise floor, for example from the left channel. -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Opaquiece, I did hear hash with the stock ww and the noise floor was lower with the linear psu. However the noise floor was lower when I plugged the ww into a power conditioner, though still louder than the elpac. My system may be more vulnerable to rfi than yours? jhm, As to price, I heard NO difference between a stock elpac, a bolder modded elpac and wayne's prototype ultimate psu NONE, zero, zilch, nada. The bolder 750.00 psu is a monumental waste of money IMO. I'm flameproof at this point so don't bother :-) ( I eat asbestos cereal for breakfast, so don't worry, you'll soon be rid of me) :-) -- tomjtx tomjtx's Profile: http://forums.slimdevices.com/member.php?userid=7449 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175706 Wrote: SB3 - custom Odyssey Audio Cyclops - BW CM4 (which are pretty good floorstanding box speakers with very high MAF/WAF). I wasn't referring to the display noise (although I see no reason why the PS would be less likely to affect that than music). I was referring to the overall noise floor, for example from the left channel. The display noise (if it's there) would be a product of the display circuit (power to the display, digital drivers, the actual display itself, etc). I don't see that an external power supply necessarily can do anything to affect that. When it comes to judging sound quality from a component's noise floor I don't get what the point would be in that? If, for example, noise introduces jitter in the D/A, it won't show up when the D/A isn't doing anything. Furthermore the D/A will not sound noisy -it will just sound bad. That is the nature of may problems in audio reproduction -they are not easily identifiable as noise freestanding from any audio signals. (Especially not by ear.) -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
tomjtx;175711 Wrote: Opaquiece, I did hear hash with the stock ww and the noise floor was lower with the linear psu. However the noise floor was lower when I plugged the ww into a power conditioner, though still louder than the elpac. My system may be more vulnerable to rfi than yours? Could be, or possibly it could be a difference in power quality. In any case for $30 or whatever it's worthwhile if it lowers the noise floor. I'll check that again later - if it's got to do with power quality maybe the differences will be more audible at peak hours versus late at night. Although I imagine my power is always pretty noisy considering the population density around here (250,000 people within a mile radius). -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
P Floding;175717 Wrote: The display noise (if it's there) would be a product of the display circuit (power to the display, digital drivers, the actual display itself, etc). I don't see that an external power supply necessarily can do anything to affect that. But you do see how it can affect music playback? When it comes to judging sound quality from a component's noise floor I don't get what the point would be in that? If, for example, noise introduces jitter in the D/A, it won't show up when the D/A isn't doing anything. Furthermore the D/A will not sound noisy -it will just sound bad. That is the nature of may problems in audio reproduction -they are not easily identifiable as noise freestanding from any audio signals. (Especially not by ear.) If the PS induces jitter in the D/A it's because there are some stray fields around which cause noise in the DAC. In that case they will also induce noise in the analogue out, and when you amplify it you should be able to hear it as increased noise floor or possibly a hum or tone. It's significant that Tom hears a lower noise floor with the linear supply - that's the first concrete piece of evidence I've heard that this upgrade does anything. In any case it would be quite easy (with the right equipment) to measure whether or not SB jitter is affected by using a linear PS. Has anyone done that? -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175723 Wrote: But you do see how it can affect music playback? If the PS induces jitter in the D/A it's because there are some stray fields around which cause noise in the DAC. In that case they will also induce noise in the analogue out, and when you amplify it you should be able to hear it as increased noise floor or possibly a hum or tone. It's significant that Tom hears a lower noise floor with the linear supply - that's the first concrete piece of evidence I've heard that this upgrade does anything. In any case it would be quite easy (with the right equipment) to measure whether or not SB jitter is affected by using a linear PS. Has anyone done that? Well, if a component (say the display system) GENERATES noise internally, it's not going to help adding a nicer external power supply. Isn't that quite obvious? I can't answer for Tom. (Perhaps he meant the percieved noise floor during playback of music?) I don't, generally, put my ear to the speakers to see if the noise floor has changed. Re. jitter: There must be some misunderstanding about how a D/A works, and/or what jitter is and how it affects the D/A process. -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
I think I'm with PF on this one - it seems to be not so much a case of the noise floor being any lower, but of RFI getting in somewhere and jittering things up... I can't hear any difference in the noise floor playing a silent WAV... (in 5.1 party - ie mono mode) and believe me with 1,340 watts waiting to throb that can be scary! but I can feel a positive difference in sound on actual music. Things seem less forced or strained when the wart is unplugged and another PSU is in place. Maybe my TACT is picking this up too? -- Phil Leigh Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Phil Leigh;175730 Wrote: I think I'm with PF on this one - it seems to be not so much a case of the noise floor being any lower, but of RFI getting in somewhere and jittering things up... I can't hear any difference in the noise floor playing a silent WAV... (in 5.1 party - ie mono mode) and believe me with 1,340 watts waiting to throb that can be scary! but I can feel a positive difference in sound on actual music. Things seem less forced or strained when the wart is unplugged and another PSU is in place. Maybe my TACT is picking this up too? Phil , I hear the same diffrence you hear when listening to music, but I also had a lower noise floor. My system may just be more susceptible. Anyway, when I get the time I'll hook up the SB again and give a re listen. Since getting the TP I've been listening to nothing else. -- tomjtx tomjtx's Profile: http://forums.slimdevices.com/member.php?userid=7449 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
P Floding;175727 Wrote: Well, if a component (say the display system) GENERATES noise internally, it's not going to help adding a nicer external power supply. Isn't that quite obvious? If that's obvious (which I don't agree it is), then it's equally obvious that the PS doesn't affect music, since your argument works just as well for that. And again, it's not only the display noise one can check, it's also the background noise from the left channel. Re. jitter: There must be some misunderstanding about how a D/A works, and/or what jitter is and how it affects the D/A process. Which is? Anyway, I'll do some more critical listening tests later in the week. So far I can't discern any difference, but maybe it's there. -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
tomjtx;175711 Wrote: jhm, As to price, I heard NO difference between a stock elpac, a bolder modded elpac and wayne's prototype ultimate psu NONE, zero, zilch, nada. The bolder 750.00 psu is a monumental waste of money IMO. I'm flameproof at this point so don't bother :-) ( I eat asbestos cereal for breakfast, so don't worry, you'll soon be rid of me) :-) I haven't heard the the Bolder PSU or the stock or modded Elpacs. Suggest you visit the Bolder forum on Audiocircle.com and post your findings on that product. My linear cost $30. Does your asbestos cereal taste better with whole milk or half half? ;-) -- jhm731 jhm731's Profile: http://forums.slimdevices.com/member.php?userid=7685 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175723 Wrote: In any case it would be quite easy (with the right equipment) to measure whether or not SB jitter is affected by using a linear PS. Has anyone done that? Everything's been done before! http://forums.slimdevices.com/showthread.php?t=24392 This is my personal favorite :-) http://forums.slimdevices.com/showthread.php?t=14589 ..Andrew L. Weekes response in particular. The question isn't does an upgraded supply make a difference, but how far can the improvement be taken- IMHO of course. -- Skunk Skunk's Profile: http://forums.slimdevices.com/member.php?userid=2685 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
jhm731;175748 Wrote: I haven't heard the the Bolder PSU or the stock or modded Elpacs. Suggest you visit the Bolder forum on Audiocircle.com and post your findings on that product. My linear cost $30. Does your asbestos cereal taste better with whole milk or half half? ;-) If I posted that on the Bolder AC all hell would break loose, even my asbestos cereal wouldn't protect me there. It's bad form to say something negative on the person's own forum. There are avid (some may say rabid) Bolder lovers on AC :-) I wouldn't want someone to electrocute me with a Bolder Ultimate PSU. Although I am sure they would say my screams had more fidelity and were more analogue like :-) -- tomjtx tomjtx's Profile: http://forums.slimdevices.com/member.php?userid=7449 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Skunk;175751 Wrote: Everything's been done before! http://forums.slimdevices.com/showthread.php?t=24392 This is my personal favorite :-) http://forums.slimdevices.com/showthread.php?t=14589 ..Andrew L. Weekes response in particular. The question isn't does an upgraded supply make a difference, but how far can the improvement be taken- IMHO of course. Right, I thought this had been done - thanks for the link. Ironic that the jitter is worse (although probably not significantly so) with the linear... -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
P Floding;175759 Wrote: It says absolutely nothing about the SMPS's possible influence on other equipment. Astute observation, but opaqueice had asked about jitter. -- Skunk Skunk's Profile: http://forums.slimdevices.com/member.php?userid=2685 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175747 Wrote: If that's obvious (which I don't agree it is), then it's equally obvious that the PS doesn't affect music, since your argument works just as well for that. And again, it's not only the display noise one can check, it's also the background noise from the left channel. Which is? Anyway, I'll do some more critical listening tests later in the week. So far I can't discern any difference, but maybe it's there. That somehow a DAC will start producing noise when nothing is played if jitter would be present when something is being played. It's like trying to check the quality of the water supply with the tap turned off. -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Not wishing to cloud the issue but what (I think) PF and I are hearing is the wall wart doing something to our TACT gear rather than anything to do with the SB itself. -- Phil Leigh Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Skunk;175764 Wrote: Astute observation, but opaqueice had asked about jitter. If used with an external DAC jitter may well be introduced by noise from the SMPS. Also, even when used with the internal DAC jitter may well result from noise (from the SMPS) being introduced in unexpected ways, that will not be visible in a lab configuration. -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Phil Leigh Wrote: Not wishing to cloud the issue but what (I think) PF and I are hearing is the wall wart doing something to our TACT gear rather than anything to do with the SB itself. I don't think your comment clouds the issue - that possibility remains. But once again, if the problem is EM interference from the switch mode PSU it should be much *more* audible without music playing or with a silent track. The TacT does some DSP. That's very unlikely to be affected by this level of EMI (otherwise your computer would crash when you plug in the PS for the SB). So the only culprit could be jitter induced by the EMI, or noise added to the analogue stage. Both are possible - Sean's measurements show that this doesn't happen with the SB, but it could with the TacT. However both are caused by the same effect - EMI making circuits noisy - and I see no reason why that would be audible in increased jitter but not as an increased noise floor. On the contrary it should be much easier to hear in the noise. But who knows - these are very complex systems. -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
P Floding;175768 Wrote: That somehow a DAC will start producing noise when nothing is played if jitter would be present when something is being played. It's like trying to check the quality of the water supply with the tap turned off. Look - if EMI is causing jitter in the DAC, it's also causing noise in the analogue circuit just downstream from the DAC. After all jitter is really an analogue phenomenon - it comes from the fact that voltage tranistions aren't perfectly sharp, and one reason for that is noise. If you don't believe me, listen to the noise floor of the SB when it's a) idle b) playing a silent track The noise level is much higher in b. Why? Because the DAC is a bit noisy. That noise will also contribute something to jitter. In fact in some ways of measuring jitter (for example, actual analogue output minus ideal output, which is what Stereophile measures when it tests jitter levels) these two phenomena aren't even possible to separate - both contribute to jitter. -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Well, I disagree. I'll give one more example which might be instructive, and this will be my last comment on the subject. Suppose there's a component of EM noise at 100Hz. Imagine adding that a) to the digital signal before the DAC b) to the analogue signal after the DAC. Is there a difference? Yes - in case a) a 1kHz test tone will have sidebands at 900 and 1100KHz, as well as a component at 100. In case b) the effect will be only to add a component at 100Hz. My point is that both a) and b) will be present if the source of the noise is EMI, but case b) will be much easier to hear (all else being equal) because you can amplify it without any background (that is, music!). The only loophole I can see here is if the interference is for some reason much stronger in the digital signal than in the analogue stage. -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Phil Leigh;175784 Wrote: It doesn't necessarily follow that EMI causing jitter would be audible as noise in the analogue stages. Jitter affects timing not the noise floor. I can't hear the wart doing anything to my DAC as far as noise floor is concerned. It seems the TACT is susceptible to induced jitter effects (my TACT has NO analogue stages in it - it is pure DSP) from EMI. I guess this could be one reason why there are aftermarket PSU's for the TACT - which I will investigate when I have some money... ok, so you use an external DAC after the TacT. Have you tried removing the TacT altogether to check if the wall wart still influences sound quality? Also, it may or not be the TacT's fault, since the interface between the two (TacT and DAC) could also be affected by the SMPS. -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175789 Wrote: Well, I disagree. I'll give one more example which might be instructive, and this will be my last comment on the subject. Suppose there's a component of EM noise at 100Hz. Imagine adding that a) to the digital signal before the DAC b) to the analogue signal after the DAC. Is there a difference? Yes - in case a) a 1kHz test tone will have sidebands at 900 and 1100KHz, as well as a component at 100. In case b) the effect will be only to add a component at 100Hz. My point is that both a) and b) will be present if the source of the noise is EMI, but case b) will be much easier to hear (all else being equal) because you can amplify it without any background (that is, music!). The only loophole I can see here is if the interference is for some reason much stronger in the digital signal than in the analogue stage. Most of what you just wrote is exactly what I have been trying to explain. When it comes to the stronger interference there is no way to compare them, as we don't know how strong their influences are at the point of influence. And, as you say ourself, the actual result of the influence is totally different. (So strength is not really relevant.) -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175789 Wrote: Well, I disagree. I'll give one more example which might be instructive, and this will be my last comment on the subject. Suppose there's a component of EM noise at 100Hz. Imagine adding that a) to the digital signal before the DAC b) to the analogue signal after the DAC. Is there a difference? Yes - in case a) a 1kHz test tone will have sidebands at 900 and 1100KHz, as well as a component at 100. In case b) the effect will be only to add a component at 100Hz. My point is that both a) and b) will be present if the source of the noise is EMI, but case b) will be much easier to hear (all else being equal) because you can amplify it without any background (that is, music!). The only loophole I can see here is if the interference is for some reason much stronger in the digital signal than in the analogue stage. But...adding a 1kHz tone to (the analogue representation of) the digital signal wont create analogue noise in the DAC - it just makes it harder for the DAC to recover the bits... The only way to increase the noise floor out of the DAC is to chaneg the bits going in, or to induce noise in the analogue op stages of the DAC. The effect of EMI on digital and analogue circuits is completely different AFAIK, -- Phil Leigh Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
Phil Leigh;175800 Wrote: But...adding a 1kHz tone to (the analogue representation of) the digital signal wont create analogue noise in the DAC - it just makes it harder for the DAC to recover the bits... Well, not really. Adding noise to the digital signal (and yes PF, by digital signal I obviously mean the electrical S/PDIF signal transmitted along the wire, not the abstract sequence of bits) will change the analogue output of the DAC. This is called jitter; it results from the fact that (most) DACs use the transitions in the digital signal as a clock. If there is noise it affects the derived time of arrival of those transtions, resulting in a jittery clock, which in turn results in a distorted output waveform. The difference between that distorted waveform and the ideal is nothing but a form of noise at the analogue output - and in fact that's exactly what Stereophile measures in their tests and refers to as jitter (but it's NOT what Sean measured - he made a direct measurement of timing variations in the digital signal). The effect of EMI on digital and analogue circuits is completely different AFAIK, In this case it is different - see my post above - but not completely so. My point stands - it stretches credulity to the breaking point to think that some jitter-induced noise overlaid on much louder music is more audible than similar noise amplified maximally and played against silence. -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175845 Wrote: Well, not really. Adding noise to the digital signal (and yes PF, by digital signal I obviously mean the electrical S/PDIF signal transmitted along the wire, not the abstract sequence of bits) will change the analogue output of the DAC. This is called jitter; it results from the fact that (most) DACs use the transitions in the digital signal as a clock. If there is noise it affects the derived time of arrival of those transtions, resulting in a jittery clock, which in turn results in a distorted output waveform. The difference between that distorted waveform and the ideal is nothing but a form of noise at the analogue output - and in fact that's exactly what Stereophile measures in their tests and refers to as jitter (but it's NOT what Sean measured - he made a direct measurement of timing variations in the digital signal). In this case it is different - see my post above - but not completely so. My point stands - it stretches credulity to the breaking point to think that some jitter-induced noise overlaid on much louder music is more audible than similar noise amplified maximally and played against silence. Distorted yes...noisy as in hissy or hummy...no. I don't really have any idea what jitter-induced noise is in any analogue sense... That's kind of the point of digital really, isn't it? You can mess with the analogue version of the digital signal (ie the spdif signal)as much as you like but so long as the right bits arrive, no noise or anything else is added. Of course if the clock recovery is getting messed-up you get jitter (not noise). That's what I hear with the wall wart in or out - zero noise in either case, but something different in the reproduction of actual music. None of what I am saying is relevant to the performance of the internal SB DAC which may well have a higher or lower analogue noise floor with different supplies - I don't know. -- Phil Leigh Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
P Floding;175883 Wrote: No, because it is not overlaid. It is correlated. You don't get similar noise from your described methods. If you have a separate DAC you can test for yourself with various transports. Yes exactly...and correlated jitter doesn't equal noise it equals odd things happening to the timing of the music imho. -- Phil Leigh Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
P Floding;175883 Wrote: No, because it is not overlaid. It is correlated. You don't get similar noise from your described methods. OK, I guess that wasn't my last post... Take the actual waveform, subtract the ideal, and that's the noise spectrum (or distortion, or choose whatever term you prefer - from now on I'll refer to it as noise). Because everything here is linear, you can think of the actual signal as the noise plus (overlaid on) the ideal signal. Some of that noise comes from jitter, and some comes from thermal noise in the analogue stage, and some comes from EMI, etc. Now, noise due to jitter is correlated with the signal in the following sense: if you add some jitter with frequency x to a signal with frequency y, you get noise concentrated at frequency y-x and y+x, as well as some other components. If you add that same interference to an analogue signal, you just get noise at x (this is what I said two posts back), so that could be said to be uncorrelated with the signal. Of course if you add full spectrum noise to the digital signal you will get full spectrum (possibly with a different shape) noise at the analogue out, so there the difference is qualitatively much less. My point, again, is that the noise due to jitter is going to be much harder to hear than the noise directly added to the analogue stage if the source of both is the same old EMI. So if you don't hear any change in the noise floor when you unplug the wallwart I'm very skeptical there can be any change when music is playing. It would be interesting to see if there's some DAC design for which this isn't true - maybe you could build a DAC which greatly amplifies jitter at certain frequencies or something... what DACs are you two using? -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175906 Wrote: OK, I guess that wasn't my last post... Take the actual waveform, subtract the ideal, and that's the noise spectrum (or distortion, or choose whatever term you prefer - from now on I'll refer to it as noise). Because everything here is linear, you can think of the actual signal as the noise plus (overlaid on) the ideal signal. Some of that noise comes from jitter, and some comes from thermal noise in the analogue stage, and some comes from EMI, etc. Now, noise due to jitter is correlated with the signal in the following sense: if you add some jitter with frequency x to a digital signal representing an analogue tone with frequency y, you get noise at the analogue output concentrated at frequency y-x and y+x, as well as some other components. If you add that same interference to an analogue signal, you just get noise at x (this is what I said two posts back), so that could be said to be uncorrelated with the signal. Of course if you add full spectrum noise to the digital signal you will get full spectrum (possibly with a different shape) noise at the analogue out, so there the difference is qualitatively much less. My point, again, is that the noise due to jitter is going to be much harder to hear than the noise directly added to the analogue stage if the source of both is the same old EMI. So if you don't hear any change in the noise floor when you unplug the wallwart I'm very skeptical there can be any change when music is playing. It would be interesting to see if there's some DAC design for which this isn't true - maybe you could build a DAC which greatly amplifies jitter at certain frequencies or something... what DACs are you two using? Your reasoning is only partially complete. In reality HF may be rejected by analogue circuits, and if they make it through you won't hear them anyway (unless mixed down into the audible spectrum by some non-linearity). In contrast HF injected into a DAC's clock (one way or another) will mix down into the audible spectrum. The resulting noise is correlated to the audio signal, and hence should be referred to as distortion -even if its properties are not a simple to pin down as normal non-linearities in analogue amplification. AND you don't get to hear this distortion separately from any signal. Comparing a low-jitter signal to a high-jitter one, just listening to the difference signal should be interesting. -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
That's a good point - that hadn't occurred to me. EMI in the range from 20kHz - 40kHz would be inaudible added to the analogue output, but jitter at that frequency could intermodulate with the digital signal to produce audible distortion. For example 25kHz jitter can produce 10kHz noise when a 15kHz signal is being played. (Note that jitter 40kHz has no effect, assuming 20kHz is the threshhold for human hearing.) For this to work as an explanation you need the EMI from the switcher to be concentrated mostly above 20kHz, which isn't consistent with the measurements in the thread Skunk linked to. But still, it's an interesting idea... what DAC do you use? Thanks for the interesting comment. -- opaqueice opaqueice's Profile: http://forums.slimdevices.com/member.php?userid=4234 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175930 Wrote: That's a good point - that hadn't occurred to me. EMI in the range from 20kHz - 40kHz would be inaudible added to the analogue output, but jitter at that frequency could intermodulate with the digital signal to produce audible distortion. For example 25kHz jitter can produce 10kHz noise when a 15kHz signal is being played. (Note that jitter 40kHz has no effect, assuming 20kHz is the threshhold for human hearing.) For this to work as an explanation you need the EMI from the switcher to be concentrated mostly above 20kHz, which isn't consistent with the measurements in the thread Skunk linked to. But still, it's an interesting idea... what DAC do you use? Thanks for the interesting comment. I use the D/A card in my TacT RCS 2.2x (which I managed to make sound pretty good again, don't ask my how). So I guess the DAC is the entire TacT -with its peculiarities. I'd like to test with a simpler DAC -preferably one without forced sample rate conversion. Might build one for this purpose. -- P Floding P Floding's Profile: http://forums.slimdevices.com/member.php?userid=2932 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175497 Wrote: Which brings me to music. So far, I don't hear any differences. I'll try again later when I have more time to listen. As I predicted in your part 1, I didn't think youd hear any difference with this cheap linear PSU. -- jhm731 jhm731's Profile: http://forums.slimdevices.com/member.php?userid=7685 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
[SlimDevices: Audiophiles] Re: plug and play linear supply (part 2)
opaqueice;175497 Wrote: Which raises an interesting question - if the stock wallwart really sounds worse than the linear, why isn't there a difference in the noise floor for the SB when it's idle or playing a silent track? Doesn't it seem odd that the effect is audible during complex musical passages, but not present at all when the noise floor is clearly audible? Which brings me to music. So far, I don't hear any differences. I'll try again later when I have more time to listen. Refer to Sean's earlier posts on this topic. his measurements suggest that there really is no difference in the performance of an SB with a linear or switching PSU, because of the internal regulation that takes place. OTOH there is plenty of evidence for severe RFI pumped out by the switching supply, and if your downstream kit is affected by it you will hear a difference. Otherwise, otherwise. Ceejay -- ceejay ceejay's Profile: http://forums.slimdevices.com/member.php?userid=148 View this thread: http://forums.slimdevices.com/showthread.php?t=32231 ___ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
