More 'Audiophile' bullsh*t

[mgv8]

TonyRPH said:

If a CD player or amplifier reacts badly to a poor quality mains feed, then something is wrong with the PSU design.

Any well regulated, well smoothed (in particular well smoothed applies to amplifiers which typically don't use a regulated PSU) should be relatively impervious to anything but the most severe corruption of the mains waveform and voltage (within reasonable limits).

This applies even more so to devices using SMPS PSUs.

Even when I lived on a farm in a rural part of SA my TV (big old CRT TV) would only occasionally flicker because the mains wasn't always particularly stable, so what makes audio stuff so special that it's not immune?
I'll tell you what makes audio so special - the 'special' golden ears brigade, that's what!!!

As for that PS audio review - the clipped mains waveform shown in one of the graphs is likely caused by something on the local mains ring, and additionally will (should!) have no affect on a competently designed PSU. Curiously, the PS Audio is quoted as having 2.36% THD (2nd and 3rd harmonic) and that amount of THD would be visible on the waveform, but yet that depicted in the image is supposedly perfect.

In fact, that device is truly fitting of this topic.

CD / DVD and TV are not that power hungry or dynamic in demands so really not that bothered about supply. A power amp is using a lot of current in a very dynamic way. Even PS Audio car clear their power regenerator is for the AMP, the other kit should just be on the filter sockets.

[TonyRPH]

mgv8 said:

CD / DVD and TV are not that power hungry or dynamic in demands so really not that bothered about supply. A power amp is using a lot of current in a very dynamic way. Even PS Audio car clear their power regenerator is for the AMP, the other kit should just be on the filter sockets.

I made a point of mentioning that I had an old CRT TV at the time - typical power consumption 350 watts - more than the average power amp.

Additionally, unless you are absolutely screwing your 200W power amp, the consumption (however dynamic) is not going to be that high - peaky but not that high.

Also, the mains is capable of delivering such high current, that a peaky load like that will not make any difference.

It's all down to power supply design - nothing more, nothing less.

I've built a couple of power amps with high current power supplies, and they simply don't care about mains quality (within reason).

If the mains was as bad as it's made out to be, computers and servers would be crashing constantly.

But it isn't, so they don't.

[Crackie]

TonyRPH said:

Crackie said:

ATG said:

Mains makes a difference if and only if the DC supply circuits in one of your components has been designed by a chimpanzee. There's just no excuse.

In that case, every CD player or amp I've owned is included. It's a bold claim to label the engineering teams at Wadia, Exposure, Quad, Cambridge Audio, Cyrus, Audio Analogue, Rotel, Naim, Yamaha, Pioneer, Sony, Phillips and Technics as chimps.

https://www.psaudio.com/wp-content/uploads/2013/03...

If a CD player or amplifier reacts badly to a poor quality mains feed, then something is wrong with the PSU design.

Any well regulated, well smoothed (in particular well smoothed applies to amplifiers which typically don't use a regulated PSU) should be relatively impervious to anything but the most severe corruption of the mains waveform and voltage (within reasonable limits).

This applies even more so to devices using SMPS PSUs.

Even when I lived on a farm in a rural part of SA my TV (big old CRT TV) would only occasionally flicker because the mains wasn't always particularly stable, so what makes audio stuff so special that it's not immune?
I'll tell you what makes audio so special - the 'special' golden ears brigade, that's what!!!

As for that PS audio review - the clipped mains waveform shown in one of the graphs is likely caused by something on the local mains ring, and additionally will (should!) have no affect on a competently designed PSU. Curiously, the PS Audio is quoted as having 2.36% THD (2nd and 3rd harmonic) and that amount of THD would be visible on the waveform, but yet that depicted in the image is supposedly perfect.

In fact, that device is truly fitting of this topic.

Hi Tony, you mentioned that there must be something wrong with the PSU design on various bits of kit I've owned. I don't agree, Naim, Wadia and Exposure in particular are renowned for the quality of their PSU designs and in my experience their products coped noticeably better with noisy mains than entry level gear...…….You went on to say any amp with a well regulated and smoothed PSU should be relatively immune to voltage fluctuations and mains borne harmonic noise; I agree but the audible improvement in the early hours was still there.

I've been involved with design and development of a couple of commercial amps and have measured / benchmarked several more. PSU design is critical but in my experience the very best commercial designs are still flawed to a degree. The THD noise on the mains is easy to measure and differences between the best and worst times are literally night and day. If you'll excuse the pun.

Regarding the PS Audio review I think you've not interpreted the info correctly. The 2.36% refers to the THD ( 2nd to 14th harmonics ) of the incoming mains supply…….the regenerated supply coming out of the P10 product was reduced to 0.53%.

[TonyRPH]

Crackie said:

Hi Tony, you mentioned that there must be something wrong with the PSU design on various bits of kit I've owned. I don't agree, Naim, Wadia and Exposure in particular are renowned for the quality of their PSU designs and in my experience their products coped noticeably better with noisy mains than entry level gear...…….

I wasn't citing your specific kit - it was a broad response - a sweeping generalisation if you like

Crackie said:

You went on to say any amp with a well regulated and smoothed PSU should be relatively immune to voltage fluctuations and mains borne harmonic noise; I agree but the audible improvement in the early hours was still there.

I've been involved with design and development of a couple of commercial amps and have measured / benchmarked several more. PSU design is critical but in my experience the very best commercial designs are still flawed to a degree. The THD noise on the mains is easy to measure and differences between the best and worst times are literally night and day. If you'll excuse the pun.

I was being generous with the use of the term relatively

You said "but in my experience the very best commercial designs are still flawed to a degree" - this is precisely what I am alluding to?

It's a contradiction of your opening paragraph!!!

Crackie said:

Regarding the PS Audio review I think you've not interpreted the info correctly. The 2.36% refers to the THD ( 2nd to 14th harmonics ) of the incoming mains supply…….the regenerated supply coming out of the P10 product was reduced to 0.53%.

You are indeed correct - I did misinterpret the test results.

I must have been lucky in the various places I have lived, as I've yet to have any issues with mains distortion, DC on the mains any such problems.

I don't doubt that the mains can be bad in some cases, e.g. buildings with lifts where there is heavy switchgear switching heavy currents and so on.

My point though stands - that if equipment was properly designed in the first place (bean counters aside) then devices like the PS Audio wouldn't be required?

The same applies to the SPDIF interfaces between CD players and DACS - the flaws are in the design and implementation rather than the actual interface standard itself, which is why, back in the 90's there were so many products that claimed to solve SPDIF issues - but if the interface had just been implemented correctly in the first place.... (and many were)

[Crackie]

TonyRPH said:

Crackie said:

Hi Tony, you mentioned that there must be something wrong with the PSU design on various bits of kit I've owned. I don't agree, Naim, Wadia and Exposure in particular are renowned for the quality of their PSU designs and in my experience their products coped noticeably better with noisy mains than entry level gear...…….

I wasn't citing your specific kit - it was a broad response - a sweeping generalisation if you like

Crackie said:

You went on to say any amp with a well regulated and smoothed PSU should be relatively immune to voltage fluctuations and mains borne harmonic noise; I agree but the audible improvement in the early hours was still there.

I've been involved with design and development of a couple of commercial amps and have measured / benchmarked several more. PSU design is critical but in my experience the very best commercial designs are still flawed to a degree. The THD noise on the mains is easy to measure and differences between the best and worst times are literally night and day. If you'll excuse the pun.

I was being generous with the use of the term relatively

You said "but in my experience the very best commercial designs are still flawed to a degree" - this is precisely what I am alluding to?

It's a contradiction of your opening paragraph!!!

Crackie said:

Regarding the PS Audio review I think you've not interpreted the info correctly. The 2.36% refers to the THD ( 2nd to 14th harmonics ) of the incoming mains supply…….the regenerated supply coming out of the P10 product was reduced to 0.53%.

You are indeed correct - I did misinterpret the test results.

I must have been lucky in the various places I have lived, as I've yet to have any issues with mains distortion, DC on the mains any such problems.

I don't doubt that the mains can be bad in some cases, e.g. buildings with lifts where there is heavy switchgear switching heavy currents and so on.

My point though stands - that if equipment was properly designed in the first place (bean counters aside) then devices like the PS Audio wouldn't be required?

The same applies to the SPDIF interfaces between CD players and DACS - the flaws are in the design and implementation rather than the actual interface standard itself, which is why, back in the 90's there were so many products that claimed to solve SPDIF issues - but if the interface had just been implemented correctly in the first place.... (and many were)

The point you make regarding the quality of the mains where you've lived is an important one. As I mentioned a couple of posts ago, the mains quality in Huntingdon was poor during the daytime and early evening and gradually improved throughout the evening until the early hours when background noise was negligible.

A PS Audio regenerator is capable of reducing mains borne THD by approx. a factor of five. Reviewer's claim the subjective benefits are significant and they purchase regenerators for their own use...….

In my experience, if you live in an area where the mains is noisy, there isn't a Hi-Fi PSU available that is immune to the effects.

It's a pity I never repeated the exercise in the early hours for comparison but there is a daytime noise floor measurement from a factory on Sapley Road Industrial Estate in Huntingdon taken in 2015.

[TonyRPH]

Crackie said:

The point you make regarding the quality of the mains where you've lived is an important one. As I mentioned a couple of posts ago, the mains quality in Huntingdon was poor during the daytime and early evening and gradually improved throughout the evening until the early hours when background noise was negligible.

A PS Audio regenerator is capable of reducing mains borne THD by approx. a factor of five. Reviewer's claim the subjective benefits are significant and they purchase regenerators for their own use...….

In my experience, if you live in an area where the mains is noisy, there isn't a Hi-Fi PSU available that is immune to the effects.

It's a pity I never repeated the exercise in the early hours for comparison but there is a daytime noise floor measurement from a factory on Sapley Road Industrial Estate in Huntingdon taken in 2015.

Without knowing exactly what your graph is representing it's difficult to pass comment.

Were you measuring a preamp, an amp, a power supply....?

At which point in the chain was the measurement taken?

Ideally I'd like to see a spectrum analysis of the raw mains before reaching any conclusions.

I measured my own mains this morning - I used a bit of a crude setup as follows:

15-0-15 toroidal -----> 50k pot ---> input buffer ---> sound card (Asus Xonar Essence STX)

As can be seen, I'm seeing THD of around 1.77% - I think some (most?) of that will undoubtedly have been added by the transformer itself.

The bottom spectrum is with the buffer box input shorted so as to show reference noise levels.

I will try to remember to measure this again late tonight.

[Crackie]

TonyRPH said:

Crackie said:

The point you make regarding the quality of the mains where you've lived is an important one. As I mentioned a couple of posts ago, the mains quality in Huntingdon was poor during the daytime and early evening and gradually improved throughout the evening until the early hours when background noise was negligible.

A PS Audio regenerator is capable of reducing mains borne THD by approx. a factor of five. Reviewer's claim the subjective benefits are significant and they purchase regenerators for their own use...….

In my experience, if you live in an area where the mains is noisy, there isn't a Hi-Fi PSU available that is immune to the effects.

It's a pity I never repeated the exercise in the early hours for comparison but there is a daytime noise floor measurement from a factory on Sapley Road Industrial Estate in Huntingdon taken in 2015.

Without knowing exactly what your graph is representing it's difficult to pass comment.

Were you measuring a preamp, an amp, a power supply....?

At which point in the chain was the measurement taken?

Ideally I'd like to see a spectrum analysis of the raw mains before reaching any conclusions.

I measured my own mains this morning - I used a bit of a crude setup as follows:

15-0-15 toroidal -----> 50k pot ---> input buffer ---> sound card (Asus Xonar Essence STX)

As can be seen, I'm seeing THD of around 1.77% - I think some (most?) of that will undoubtedly have been added by the transformer itself.

The bottom spectrum is with the buffer box input shorted so as to show reference noise levels.

I will try to remember to measure this again late tonight.

The measurement was just a looped input to output 'calibration' check. The 'soundcard' was a Tascam audio interface.

Thanks for taking the time to make some measurements Tony...…..virtual pint to you from me.
It will be interesting to what degree the 'late' measurement is better than daytime...…..if at all where you live.

Can you run a straight in to out loop ( with buffer ) i.e. just the signature of the buffer, Asus and inherent noise but no pot and no T-X?

Edited by Crackie on Friday 17th May 16:30

[TonyRPH]

Crackie said:

<snip>

Can you run a straight in to out loop ( with buffer ) i.e. just the signature of the buffer, Asus and inherent noise but no pot and no T-X?

I already did - that's bottom most graph!

Unless you want to see Asus ---> buffer ---> Asus ???

Edit:

This is: PC ----> USB to SPDIF ---> DAC ---> buffer --> Asus (this is my usual testing chain)

I usually see a slightly lower noise floor than this - however I have a CD player open and running on my bench (amongst other things!) so the noise floor is a bit higher than usual.

In the above setup, the reference level is 0dB (I also usually use -6dB that might explain he higher noise floor).



Here's another with a 1kHz tone injected from the PC which shows SNR / SINAD and THD at -6dB

Edited by TonyRPH on Friday 17th May 17:15

[Crackie]

TonyRPH said:

Crackie said:

<snip>

Can you run a straight in to out loop ( with buffer ) i.e. just the signature of the buffer, Asus and inherent noise but no pot and no T-X?

I already did - that's bottom most graph!

Unless you want to see Asus ---> buffer ---> Asus ???

Edit:

This is: PC ----> USB to SPDIF ---> DAC ---> buffer --> Asus (this is my usual testing chain)

I usually see a slightly lower noise floor than this - however I have a CD player open and running on my bench (amongst other things!) so the noise floor is a bit higher than usual.

In the above setup, the reference level is 0dB (I also usually use -6dB that might explain he higher noise floor).



Here's another with a 1kHz tone injected from the PC which shows SNR / SINAD and THD at -6dB

Edited by TonyRPH on Friday 17th May 17:15

All good Tony......I was just interested to see as few variables in the chain as possible. Look forward to seeing the early hours measurements in due course...……

Friday night / Sat morning might not be a great time to do this experiment; it could be pretty noisy then too. People coming home from the pub etc ......I know I might be.

[Rostfritt]

TonyRPH said:

No, that's just poor power supply or amplifier design - or - that amp was optimised (or even configured?) for 240v operation, and 218v was simply too low for it..

I suspect that as the mains voltage dropped, the quiescent current of the amp went up, loading the power supply excessively and causing hum.

Mechanical transformer hum is caused by DC on the mains, or it could simply be poor quality transformers.

I guess it's not inconceivable that as your mains voltage went higher, that the DC level increased (or possibly just appeared it not there at the lower voltage).

If it takes so much to get rid of power supply hum, why don't they just run top end equipment off a large battery? Surely if your equipment could be wired to take a DC supply, you could just rig up a couple of leisure batteries to give you enough power for the evening?

[Gary C]

Rostfritt said:

TonyRPH said:

No, that's just poor power supply or amplifier design - or - that amp was optimised (or even configured?) for 240v operation, and 218v was simply too low for it..

I suspect that as the mains voltage dropped, the quiescent current of the amp went up, loading the power supply excessively and causing hum.

Mechanical transformer hum is caused by DC on the mains, or it could simply be poor quality transformers.

I guess it's not inconceivable that as your mains voltage went higher, that the DC level increased (or possibly just appeared it not there at the lower voltage).

If it takes so much to get rid of power supply hum, why don't they just run top end equipment off a large battery? Surely if your equipment could be wired to take a DC supply, you could just rig up a couple of leisure batteries to give you enough power for the evening?

Which is exactly what one manufacturer did, cant remember its name.

[And then she]

Gary C said:

Which is exactly what one manufacturer did, cant remember its name.

Here's the one I remember:

https://audio-database.com/MARANTZ/amp/sc-5-e.html

[TonyRPH]

Rostfritt said:

If it takes so much to get rid of power supply hum, why don't they just run top end equipment off a large battery? Surely if your equipment could be wired to take a DC supply, you could just rig up a couple of leisure batteries to give you enough power for the evening?

TLDR; man has random ramble about power supplies.

The reality of it is that hum (really ripple) is not really an issue with a competent power supply design.

Part of the problem (in power amp design) is the transient (or peak) demand on the power supply.

For example a preamp will generally use a well regulated, low noise power supply (easily achieved with regulator ICs) as the demand for power is low, and the current demanded is usually constant and relatively low.

In the case of a class A design (preamp) the current demand could be high, however it's still relatively constant regardless of volume etc.

So for a typical (non Class A) preamp, battery operation is quite feasible (if unnecessary).

But the power amp is a different beast, because it has to provide huge amounts of power in bursts (depending on the demands of the music and speaker load of course) however typically it can still have to deliver 1 - 2 amps fairly constantly into an average sort of load at moderate volumes, with peaks of up to 30A or more (again, dependant on load).

This makes battery operation for power amps non viable, as you need high voltage batteries (50 to 100 Vdc +) with huge current capability, and of course these batteries will need high capacity to maintain a charge for several hours on end. Not practical at all.

In the case of a Class A power amplifier - the situation is even worse as they demand high current even when the amplifier is idle, and will very quickly drain a battery.

Class T / D is more efficient, however the current drawn when running at high volume is still quite demanding.

There are other methods of providing power - for example high power car amplifiers use a switched mode PSU to step the 12 Vdc up to +-40 - 60 Vdc - however the current demands remain the same - you will quickly deplete a 12 V battery.

Finally, revisiting the 'hum' issue...

With suitable PSU design and large reservoir capacitors, hum (it's really 'ripple') can be suppressed relatively well.

This is why I question exotic mains cables, power regenerators etc. as to my mind, in power amplifiers, ripple (caused by peak demands on the power supply) is the biggest issue, but it's effects can largely be mitigated against by competent design...

So long as the mains voltage is constant (usually a given in all but the worst cases - and then there are likely faults present) so called 'noisy' mains simply should not be an issue (IMHO).

As per above - this is even less of an issue for low current devices like preamps, DACs etc. etc.

Apologies for the long ramble.

Edited by TonyRPH on Wednesday 22 May 06:35

[WinstonWolf]

Crackie said:

Chimune said:

Crackie said:

I agree with the part in bold...….particularly the last sentence regarding the mains 'quality'.

Can you expand on your thoughts a bit please?

In my experience, you can hear and measure, a lower noise floor in the early hours relative to daytime hours and the evening time.

The differences are not subtle and have been noticeable with every piece of equipment I've owned. Mains borne noise was bad when I lived in Huntingdon; daytime noise was industrial particularly bad. Domestic noise was pretty bad in the evenings too and noticeably improved as the evening progressed; in the early hours of the morning the background hash of white noise is almost inaudible.

You can measure your noise floor using freeware like this http://audio.rightmark.org/index_new.shtml

Companies such as Accuphase, PS Audio, Isotek, manufacture mains 'regenerators' to tackle the issue.

I started a thread on PH about the subject in 2009.... https://www.pistonheads.com/gassing/topic.asp?h=0&...

That white noise could just be noise from outdoors unless you're listening in a soundproof booth...

I'd love to see some of your audiograms

[Crackie]

WinstonWolf said:

Crackie said:

Chimune said:

Crackie said:

I agree with the part in bold...….particularly the last sentence regarding the mains 'quality'.

Can you expand on your thoughts a bit please?

In my experience, you can hear and measure, a lower noise floor in the early hours relative to daytime hours and the evening time.

The differences are not subtle and have been noticeable with every piece of equipment I've owned. Mains borne noise was bad when I lived in Huntingdon; daytime noise was industrial particularly bad. Domestic noise was pretty bad in the evenings too and noticeably improved as the evening progressed; in the early hours of the morning the background hash of white noise is almost inaudible.

You can measure your noise floor using freeware like this http://audio.rightmark.org/index_new.shtml

Companies such as Accuphase, PS Audio, Isotek, manufacture mains 'regenerators' to tackle the issue.

I started a thread on PH about the subject in 2009.... https://www.pistonheads.com/gassing/topic.asp?h=0&...

That white noise could just be noise from outdoors unless you're listening in a soundproof booth...

I'd love to see some of your audiograms

If you still have a CD player, play a track pause it and then turn up amp volume as high as you dare. I'd be very surprised if you can't hear a lower noise floor at 3.00am relative now. i.e. 7.00 pm.

[TonyRPH]

Crackie said:

If you still have a CD player, play a track pause it and then turn up amp volume as high as you dare. I'd be very surprised if you can't hear a lower noise floor at 3.00am relative now. i.e. 7.00 pm.

The only real way to prove this would be to play a track of digital silence, as the mute function will generally disconnect* the output stage of the CD player from the input of the amp / preamp, leaving the preamp input floating - which will naturally raise noise levels regardless.

• some players mute by means of a relay some use transistor muting - there will be noise differences between the two.

[Crackie]

TonyRPH said:

Crackie said:

If you still have a CD player, play a track pause it and then turn up amp volume as high as you dare. I'd be very surprised if you can't hear a lower noise floor at 3.00am relative now. i.e. 7.00 pm.

The only real way to prove this would be to play a track of digital silence, as the mute function will generally disconnect* the output stage of the CD player from the input of the amp / preamp, leaving the preamp input floating - which will naturally raise noise levels regardless.

• some players mute by means of a relay some use transistor muting - there will be noise differences between the two.

Fair point Tony, but subjectively, if you're comparing apples with apples, it shouldn't matter.

If the player mutes via a relay, that's a good thing because it would eliminate another layer of circuitry that could influence the result. We're trying to understand the influence of mains borne noise without anything else present in the chain.

[TonyRPH]

The problem I have with this is that (in my case for example) the noise floor is already around -160dB, which is well, well below the threshold of audibility.

So even if the noise floor rises by 30dB or 40dB - you're still not going to hear any difference.

And additionally, the PSU ripple / noise of a power amp playing at even moderate levels of 10 - 20 watts is going to completely swamp any potential mains borne noise (not to mention the THD of the speakers and other devices in the chain).

Even listening with headphones it is highly unlikely that any mains borne noise is going to rise above the threshold of other noise and distortion contributed by the source, headphone amp and headphones.

Certainly, if you have a poorly suppressed appliance or light switch, then the odd 'pop' will certainly be audible, but there's no need to buy a dedicated mains clean up device to mitigate against this - just get the appliance and light switch fixed...

Of course, a dedicated mains spur will help here, but it's not really necessary (see above re getting appliance fixed).

Incidentally - the -160dB noise floor I see is measured via a (so called) noisy computer, which again goes to prove the bullst surrounding the use of special USB cables, audio cables etc. etc. etc.

Here is my setup used to make the measurements referred to above. As can be seen, no attention has been given to reducing interference from adjacent devices, no fancy cables, mains running close by (hence the 50Hz bump) - there is however a well shielded cable running from the buffer box to the PC, but that's only because it's 1M long, but that too is running adjacent to mains and USB cables.

I think it's clear to see that the notion of mains noise filters, regenerators etc. is just apt for this thread.

[WinstonWolf]

Crackie said:

WinstonWolf said:

Crackie said:

Chimune said:

Crackie said:

I agree with the part in bold...….particularly the last sentence regarding the mains 'quality'.

Can you expand on your thoughts a bit please?

In my experience, you can hear and measure, a lower noise floor in the early hours relative to daytime hours and the evening time.

The differences are not subtle and have been noticeable with every piece of equipment I've owned. Mains borne noise was bad when I lived in Huntingdon; daytime noise was industrial particularly bad. Domestic noise was pretty bad in the evenings too and noticeably improved as the evening progressed; in the early hours of the morning the background hash of white noise is almost inaudible.

You can measure your noise floor using freeware like this http://audio.rightmark.org/index_new.shtml

Companies such as Accuphase, PS Audio, Isotek, manufacture mains 'regenerators' to tackle the issue.

I started a thread on PH about the subject in 2009.... https://www.pistonheads.com/gassing/topic.asp?h=0&...

That white noise could just be noise from outdoors unless you're listening in a soundproof booth...

I'd love to see some of your audiograms

If you still have a CD player, play a track pause it and then turn up amp volume as high as you dare. I'd be very surprised if you can't hear a lower noise floor at 3.00am relative now. i.e. 7.00 pm.

Prepare to be surprised, I can't hear a smoke alarm test signal when I'm stood under it if I block one ear

I used to have good hearing, unfortunately I'm pretty much mono these days hence having a good understanding of which frequencies we can actually hear. A lot of theoretical discussions fail to take account of the background noise that's present in day to day life.

[silentbrown]

Crackie said:

If you still have a CD player, play a track pause it and then turn up amp volume as high as you dare. I'd be very surprised if you can't hear a lower noise floor at 3.00am relative now. i.e. 7.00 pm.

I'm not sure what you think this would prove, anyway. It's on a par with saying your car will be faster if you chuck out the sweet wrappers from the ashtray.