Yeah, cool piece of gear for $221.50....$4k+ from used test equipment vendors.
55Hz is a fundamental musical note...there are no multiples of 50Hz or 60Hz in the musical scale according to this chart - Note Frequencies .
Like I said this is preliminary informal testing but so far the subjective results hold true.
Dan.
Will do. About to move house so formal results will be a little while.
A not very common piece of gear I expect at $14k new !.
See this thread for internal pics - http://www.diyaudio.com/forums/equipment-tools/240274-ultimate-variac-kikusui-pcr-500l.html
Dan.
A decent recording should not have noticeable amounts of mains hum, unless it comes from guitar amps. If present, recording hum may cause beats with playback hum which is likely to be at a slightly different frequency - maybe up to 0.2Hz or so. This could test the subsonic performance of the equipment, causing IM. Shifting these beats and/or IM to 5Hz could make a difference. Whether better or worse I would not like to guess.Max Headroom said:
You could have hours of fun with that kit!
Different Difference Frequencies....
I have not yet tried 50Hz/60Hz, +/- say 0.2Hz but this is already on the agenda.
I am thinking that the issue is more to do with playback equipment psu ripple and lack of PSRR/bad earthing interacting (IM) with musical frequencies.
The frequency chart that I referenced is not set in stone...there are tunings slightly different to the standard 440Hz 'A' reference.
The Kikusui has 0.01Hz resoloution, and this may be useful to really fine tune into particular recordings....I may have to break out my Stax electrostatic headphones to really home in on the artefacts and find a best null AC frequency.
If all systems had perfect supplies and infinite PSRR this would all be moot...right now I am exploring this distortion mechanism in 'normal' systems.
Much more time wasting to come 😉.
Dan.
Good points, though I don't think the issue is particularly to do with recorded hum, although this is a factor, hence my comment of 60Hz recordings sounding less bad with 60Hz power, ditto 50Hz rec/pb.
I have not yet tried 50Hz/60Hz, +/- say 0.2Hz but this is already on the agenda.
I am thinking that the issue is more to do with playback equipment psu ripple and lack of PSRR/bad earthing interacting (IM) with musical frequencies.
The frequency chart that I referenced is not set in stone...there are tunings slightly different to the standard 440Hz 'A' reference.
The Kikusui has 0.01Hz resoloution, and this may be useful to really fine tune into particular recordings....I may have to break out my Stax electrostatic headphones to really home in on the artefacts and find a best null AC frequency.
If all systems had perfect supplies and infinite PSRR this would all be moot...right now I am exploring this distortion mechanism in 'normal' systems.
Haha, yes many hours of educational fun for all involved...so far my system just sounds that bit cleaner, more musical and 'correct'.
Much more time wasting to come 😉.
Dan.
Same, But Different....
I need more listening to characterise the difference.
This is revealing/interesting...swapping phase of particular harmonics changes the waveform...and the sound.
Fourier Series Applet
Dan.
WRT to 55Hz, shifting the supply +/- 5Hz for a particular recording makes a subtle difference, similar, but different.
I need more listening to characterise the difference.
This is revealing/interesting...swapping phase of particular harmonics changes the waveform...and the sound.
Fourier Series Applet
Dan.
Interesting Max. I have no idea WHY it should make a difference, but I believe you. This is how we find out new things. We have to TRY, not just presume that we know everything that will work in advance.
Yes, but never-the-less, if I heard such an improvement at a different mains frequency, I would be pouring over my PSU circuit diagram to see what extra filtration measures where needed to made the amp impervious to this and any other characteristics of the mains supply.
It probably IS possible to eliminate the effect of a small change in frequency, but WHY did the original design have this sensitivity? That is what we have to pursue.
You assume it did. Fortunately, Max is bright enough and open-minded enough to realize that he has more work to do before he can claim that the audibility actually is "real." If it is, then it's straightforward to figure out why- for example, a marginal power transformer or insufficient ripple filtering. If it isn't, he can move on and leave the Tinkerbell stuff to others.
Do not make the assumption that the power supply is the only pathway for the powerline related noise to affect the audio system. many things from transformer vibration to magnetic fields from power cords getting into the circuitry could have an effect on the audio. Some of those may be much greater than we generally expect.
The PSaudio power plant has many of these capabilities as well.
Separating the possibilities is a lot of work. And the fans running in the next room could have as much impact (white noise floor from the air movement masking other stuff) as the power frequency. There are many hours of experiments ahead and then proper validation (even the horrid DBT).
Sometimes these discoveries are more a curse than a revelation if you take them seriously.
The PSaudio power plant has many of these capabilities as well.
Separating the possibilities is a lot of work. And the fans running in the next room could have as much impact (white noise floor from the air movement masking other stuff) as the power frequency. There are many hours of experiments ahead and then proper validation (even the horrid DBT).
Sometimes these discoveries are more a curse than a revelation if you take them seriously.
Max, do your active speakers have a switched power supply or a mains transformer? Just trying to figure it out. I can follow your logic, but have questions too.
There's no magic involved, John. I've already mentioned have done simulations of what happens in a power amp when the whole path is modelled, from imperfect, conventionally distorted mains power fed through real world power supply components, with all their well known parasitics, to the voltage rails of circuitry with so-so PSRR, working under load.
Perhaps the big surprise is that the sound still sounds reasonable, most of the time, 😀 ....
Could it be that the 5Hz differential acts in a way which isolates the other (noisy) equipment in the house/area? IF so, then a lot of grunge is kept away from the system.
A few years ago I disconnected every electrical circuit in the house - with the exception of the sound chain - by throwing the circuit breakers. The effect was obvious and gave similar results to those given above. I then had a new very heavy spur, with a hard wire fuse, direct from the el supply board for the house, along with a proper dedicated external earth for the audio alone. That exercise was well worth the effort and the costs involved.
A few years ago I disconnected every electrical circuit in the house - with the exception of the sound chain - by throwing the circuit breakers. The effect was obvious and gave similar results to those given above. I then had a new very heavy spur, with a hard wire fuse, direct from the el supply board for the house, along with a proper dedicated external earth for the audio alone. That exercise was well worth the effort and the costs involved.
Yes, everyone should try the whole house electrical shutdown, at least once, to see if there is an effect - or perhaps more importantly, whether they're sensitive to the SQ changes that usually result ...
Bog Standard.....
Line level/crossover stages hanging off LM7815/7915 regulators.
View attachment B2031 - AMPS PSU.pdf
View attachment B2031 - LINE LEVEL.pdf
Dan.
Standard toroid transformer/rect/caps driving LM3886 amplifiers.
Line level/crossover stages hanging off LM7815/7915 regulators.
View attachment B2031 - AMPS PSU.pdf
View attachment B2031 - LINE LEVEL.pdf
Dan.
Totally Conventional...
These boxes run simplest PSU arrangements possible, so AC line dependency is to be expected IMO/IME.
Dan.
Hi John, see my above post, including schematics.
These boxes run simplest PSU arrangements possible, so AC line dependency is to be expected IMO/IME.
Dan.
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Local Blackout.....
Dan..
Yes, have done that plenty in the past.....agreed that sound typically cleans/improves with pretty much any system.
Dan..
Well, Max, at least you continue to 'believe' that you hear a difference. That is the important thing.
Yeah, It Is A Wonder....
Ability to provide variable frequency clean AC is one reason, experimenting with adding repeatable various amounts and kinds of 'dirt' is another reason.
Dan.
Yes.....that is the point of my buying this box.
Ability to provide variable frequency clean AC is one reason, experimenting with adding repeatable various amounts and kinds of 'dirt' is another reason.
Dan.
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