The Audiophoolery Thread.

[deliverance]

The seller must be low on dollars for Christmas

[Al (astral highway)]

I recently improved the sound quality of my home system by about 0.7%, by paying attention to the quality of the mains itself and I highly recommend doing this.

It's a bit beyond me but this is what the brochure says:

"A Rubidium reference signal is generated at 1 MHz. This is divided by logic chips to produce a sine wave of exactly 50 Hz. We use this to drive
a synchronous motor that is phase-locked to the 50 Hz divider signal via a motor-control loop.

This operates a rotating disk whose instantaneous angular velocity is frequency-locked to the rubidium clock. A precision IR LED array behind the wheel creates a 50 Hz optical strobe, and every slot passing the photodiode produces a pulse.

Since the disk speed is locked to the rubidium clock, the burst rate is exactly 50 Hz. This produces a stroboscopic “optical mains", using our proprietary technology.

As a back up, the rotational speed of a 50 kg flywheel made of titanium alloy is constantly sampled by an optical encoder referenced back to the rubidium clock.

The amplifier output is modulated so that if the flywheel drifts by even a milliradian, the system injects "corrective power". The whole system is nothing short of a mechanically stabilised, rubidium-locked local grid."

Has anyone else gone for this sort of system?

[Trevor]

This rubbish was one of the reasons I left the trade These shysters were getting every where in the late 80's The hi-fi mags in general did not really help
Trev

[elanman99]

Originally Posted by Al (astral highway)

I recently improved the sound quality of my home system by about 0.7%, by paying attention to the quality of the mains itself and I highly recommend doing this.

It's a bit beyond me but this is what the brochure says:

"A Rubidium reference signal is generated at 1 MHz. This is divided by logic chips to produce a sine wave of exactly 50 Hz. We use this to drive
a synchronous motor that is phase-locked to the 50 Hz divider signal via a motor-control loop.

This operates a rotating disk whose instantaneous angular velocity is frequency-locked to the rubidium clock. A precision IR LED array behind the wheel creates a 50 Hz optical strobe, and every slot passing the photodiode produces a pulse.

Since the disk speed is locked to the rubidium clock, the burst rate is exactly 50 Hz. This produces a stroboscopic “optical mains", using our proprietary technology.

As a back up, the rotational speed of a 50 kg flywheel made of titanium alloy is constantly sampled by an optical encoder referenced back to the rubidium clock.

The amplifier output is modulated so that if the flywheel drifts by even a milliradian, the system injects "corrective power". The whole system is nothing short of a mechanically stabilised, rubidium-locked local grid."

Has anyone else gone for this sort of system?

What brochure is that in?

Ian

[Al (astral highway)]

Originally Posted by elanman99

What brochure is that in?

Ian

I literally just made it up, Ian, in the spirit of things! . Perhaps I should go into the business?! I'm preparing drawings.

[elanman99]

Originally Posted by Al (astral highway)

I literally just made it up, Ian, in the spirit of things! . Perhaps I should go into the business?! I'm preparing drawings.

Hmmph!
Oh, what a pity. I was starting to work out how I could make one for myself.

Ian

[Al (astral highway)]

Originally Posted by elanman99

Hmmph!
Oh, what a pity. I was starting to work out how I could make one for myself.

It would undoubtedly be a thing of great beauty and precision!

[Radio Wrangler]

A couple of points. Rubidium sounds exotic, but Caesium is currently definitive and Rubidium cells have somewhat limited life expectancy.

Titanium's super power is low density with strength. The low density is not an ideal characteristic in flywheels. Certainly not at such low rotational velocities.

'Atomic clock' frequency standards are super-stable long term, but have surprising amounts of short-term jitter. If used for anything important, it is usual to phase lock a very clean quartz crystal oscillator to them with a very slow PLL. You get the cleanliness of the Quartz oscillator and the long term stability of the atomic stuff.

It's always fun to chuck some real science at the pseudo stuff.

David

[Al (astral highway)]

Originally Posted by Radio Wrangler

Titanium's super power is low density with strength. The low density is not an ideal characteristic in flywheels. Certainly not at such low rotational velocities.

That was part of my very dry joke, David!

[mark_in_manc]

But imagine the size of the flywheel! It could have curly spokes and be really Jules Verne

I'm glad to no longer be in acoustics for this kind of reason. I have a part-time job in a Civils lab, where if the beam is ******, it's ******

[Al (astral highway)]

Originally Posted by mark_in_manc

But imagine the size of the flywheel! It could have curly spokes and be really Jules Verne

I like it, I like it! I'm almost tempted to build this nonsense now I've described it. I can guarantee I could sell one, as it would look absolutely mint!

[Radio Wrangler]

Modern psycho-acoustics is about 5% acoustics and 95% psycho, by volume.

David

[Ed_Dinning]

Sound pressure volume or physical volume David?

Ed

[Craig Sawyers]

Originally Posted by Radio Wrangler

It also serves to replace your entire amplifier..... what was that quote?

"A piece of plywood, with gain."

David

For the closest approach to the original snake oil

[The Philpott]

I thought something smelt a bit off, Al..

I particularly like the turbo-encabulatoresque feedback loop between the atomic clock and the flywheel.

Dave

[Craig Sawyers]

All this stuff about flywheels reminds me of Eric Laithwaite (the guy who invented mag lev transport - through the linear induction motor).

Laithwaite was alas bamboozled by the action of a gyro, believing he had found a new law of nature if the gyro was on a frictionless surface (ice).

Richard Feynman was asked about this, and was moderately scathing, as Feynman could be when confronted with pseudoscience.

A second recollection. We were visited, when I worked for PA Technology, by a captain of industry (name withheld!). He brought a nutter along, who also believed he had found a new law of nature. This guy assembled a large dexion frame, and had a truly massive flywheel on bearings attached to the frame by a length of thread at each end of the axle. He spun up this flywheel, and intoned that the centre of mass was equidistant between the theads. The then burnt one thread with a lighter. The flywheel then started to precess. He then stated that the centre of mass had clearly moved from midway between the threads to just one thread. He honestly believed he had magically moved the centre of mass without doing work. Where on earth could you start with that? We could not instantly debunk this nonsense, because the captain of industry was clearly taken in (and we were trying to get a big project development for him).

Finally, motor driven flywheels - called Reaction Wheels - are used to do attitude correction of spacecraft. If you just use attitude thrusters the corrections are crude, and you waste fuel. So you use Reaction Wheels instead. They are not super reliable. You in principle need four in a tetrahedral arrangement, but space mission problems as a result of reaction wheel failure means the more recent missions have multiple redundancies. So if one keels over, a new one is turned on.

Craig

[Al (astral highway)]

Originally Posted by The Philpott

I particularly like the turbo-encabulatoresque feedback loop between the atomic clock and the flywheel.

haha, glad you enjoyed that, Dave!

I thought the seven layers of redundancy (arguably eight) was on point for a high-spending potential buyer

[The Philpott]

David mentions an actual 'shop' (are there such things...!?) in Post No. 3969, which has the overpriced tat in the window; this attracts attention (although not all of it will necessarily be good) therefore people will actually go in for a laugh and provided they're not thrown out in the first 120 seconds they may buy something from the more sensible end of the spectrum. This is likely to be how it works, but alternative theories are welcome.

Dave

[mole42uk]

I think I'd like the flywheel signal referenced to the GPS satellite signal and cross-referenced to the rubidium clock to increase the accuracy of the 50Hz oscillator.

[Al (astral highway)]

Originally Posted by mole42uk

... I'd like the flywheel signal referenced to the GPS satellite signal and cross-referenced to the rubidium clock to increase the accuracy of the 50Hz oscillator.