Lock Down's Effect on the Audio Systems Replay Environment

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Nick
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#16 Re: Lock Down's Effect on the Audio Systems Replay Environment

Post by Nick »

chris661 wrote: Sun Jun 07, 2020 1:44 pm I probably have a bit of Pro Sound bias going on here, but IMO if your equipment's PSU can't make a clean DC rail from a slightly-messy AC line, then it is faulty and should be fixed/replaced.

Even my old Behringer iNukes worked fine on a squishly supply that dropped to 200v under load.

Ditto regarding vibrations. Sometimes you've got to put the amp rack and mixing desk* just behind the stacks with kilowatts of subwoofer running at full-tilt.
*Remember the mixing desk will be taking in millivolt levels from microphones and applying 40+dB of gain.

While HiFi gear doesn't necessarily need to be as physically rugged as PA equipment, I do think HiFi gear should also be designed to work fine under those conditions.

Chris
The problem is that different people have different definitions of "fine". Just working is not the entirety of the goal.
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#17 Re: Lock Down's Effect on the Audio Systems Replay Environment

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The Data/Research shows that constant noise met in Urban Environments is Carcinogenic
I would like to see some citations for that claim.
I really hope that the Benefits of such an environment becomes a desirable commodity,
Just to give the contrary view on that, I would point to the number of city centre live music venues that have been forced to close up shop because of the change of use of nearby offices into accommodation.
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#18 Re: Lock Down's Effect on the Audio Systems Replay Environment

Post by JohnG »

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6173937/

I first heard of the Urban Noise Pollution being a Carcinogen many years ago on a Radio 4 Interview with a
Scandinavian who was referencing the available research to verify the need to produce quieter Urban Areas.
I recall Quieter Tyres was a way forward, as the ambient db could be reduced quite a bit.
I don't recall all the measures being proposed.

The Link is a Research I just hunted down to add a little support to the reasoning behind creating a decreased ambient noise level in Urban Areas.
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#19 Re: Lock Down's Effect on the Audio Systems Replay Environment

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That 2018 paper contains the following sentence "We did not adjust for air pollution in the main model, since air pollution is still not recognized as a risk factor for BC". The BMJ contains this 2018 paper "Atmospheric fine particulate matter and breast cancer mortality: a population-based cohort study"

https://bmjopen.bmj.com/content/6/11/e012580

Poor rats.

[quote][A recent experimental study found that rats exposed to noise (105 dB) for 30 days had significantly higher serum levels of malondialdehyde (MDA) and lower total antioxidant capacity (TAC), biomarkers of oxidative stress, than nonexposed rats [13]./quote]
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#20 Re: Lock Down's Effect on the Audio Systems Replay Environment

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Going off at a tangent a bit, I was interested to read: https://www.bbc.co.uk/news/science-environment-52973089
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#21 Re: Lock Down's Effect on the Audio Systems Replay Environment

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Neal wrote: Tue Jun 09, 2020 10:05 am Going off at a tangent a bit, I was interested to read: https://www.bbc.co.uk/news/science-environment-52973089
Good news, although I still use a tiny bit for my old mobile phone. :lol:
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#22 Re: Lock Down's Effect on the Audio Systems Replay Environment

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Nick wrote: Sun Jun 07, 2020 4:25 pm
The problem is that different people have different definitions of "fine". Just working is not the entirety of the goal.
Yep, very true. In the case above, it was getting through the gig when the generator (with a 32A Ceeform outlet) shut down and refused to turn over (I suspect lack of oil), so we had to run about 150m of 13A extension leads from the nearest building to the stage.

I do think my point stands, though, that any half-decent PSU should be able to make a clean DC rail from imperfect mains.

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#23 Re: Lock Down's Effect on the Audio Systems Replay Environment

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chris661 wrote: Tue Jun 09, 2020 11:47 am
I do think my point stands, though, that any half-decent PSU should be able to make a clean DC rail from imperfect mains.

Chris
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#24 Re: Lock Down's Effect on the Audio Systems Replay Environment

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Years ago there was talk about making a 3 Phase supply By spinning a three phase motor with a single phase and taking its output. Ok u then need 3 phase power transformer and more rectifiers. But after that it should have no noise but what it causes. If it’s an induction motor it would be best, quieter and no long term failure mechanisms. Induction motor washing machines the motor was never youre fault when I repaired them in London.
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#25 Re: Lock Down's Effect on the Audio Systems Replay Environment

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Paul Barker wrote: Tue Jun 09, 2020 6:35 pm Years ago there was talk about making a 3 Phase supply By spinning a three phase motor with a single phase and taking its output. Ok u then need 3 phase power transformer and more rectifiers. But after that it should have no noise but what it causes. If it’s an induction motor it would be best, quieter and no long term failure mechanisms. Induction motor washing machines the motor was never youre fault when I repaired them in London.
The rectifying of 3 phase leaves you with more b+ from choke input, if memory serves me right from absorbing Terman in the ‘90s. Don’t know if I could find the right Terman edition let alone chapter and verse. But that much I’m sure I’ve remembered right.
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#26 Re: Lock Down's Effect on the Audio Systems Replay Environment

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The rectifying of 3 phase leaves you with more b+ from choke input,


I would think so as rectified three phase never goes down to zero unlike rectified single phase. That in itself would reduce ripple.

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#27 Re: Lock Down's Effect on the Audio Systems Replay Environment

Post by chris661 »

Just looks like a higher mains frequency to me.

Something that would be easier to try would be to use a reasonably large solid-state amplifier connected to a step-up transformer. Should put mains THD down to basically zero, although I do wonder how an amp would react to the short-term large current requirements of a linear PSU.

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#28 Re: Lock Down's Effect on the Audio Systems Replay Environment

Post by Nick »

Just looks like a higher mains frequency to me
You need to look a little closer then

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