Snake Oil Department, Top This

[mansr]

What is an “active shield”?

Iron Dome?

 

[IPunchCholla]

What is an “active shield”?

I’m not really sure. His speaker cables were powered. Not an amp. A power source for the cables themselves. It was supposed to prevent electric shock interference, by using electricity. I searched for them but can’t find them online.

Edit. I think they were some kind of esoteric “dielectric biasing” gear.

 

[DonR]

What is an “active shield”?

Superconducting electrons in a nano quantum field.

 

[voodooless]

What is an “active shield”?

Ignorance by choice?

 

[Holmz]

Ignorance by choice?

Nope.
I don’t choose to be, I just am.

(Sort of like Popeye.)

 

[voodooless]

Nope.
I don’t choose to be, I just am.

That's a passive shield

 

[noiseangel]

Stage III Concepts Cerberus - Nirvana Sound

Ultimate Statement Silver/Palladium Cables

nirvanasound.com

2 mtrs for $57000 Australian. These are value for money quick everyone rush out and buy them.

You can get 21 ounces of 99.999% pure gold for the same price. Each to their own

 

[Spkrdctr]

Stage III Concepts Cerberus - Nirvana Sound

Ultimate Statement Silver/Palladium Cables

nirvanasound.com

2 mtrs for $57000 Australian. These are value for money quick everyone rush out and buy them.

You can get 21 ounces of 99.999% pure gold for the same price. Each to their own

I would gladly take the gold! Better than cheap copper wiring.

 

[High End Refugee]

Thanks for the response, but it leaves me uncertain.
Have you ever actually seen a clamp at the centre of a disc, properly flatten a warp at the rim? I spent some time looking at this, and while a warp through the middle of the disc (most common in my experience) can sometimes be reduced a little, the effect was overstated as I saw it.
As for wow/flutter, a weight at the middle of the disc reduces the flywheel effect, which should reduce inertia and increase wow.

A lot of the claims for weights and mats are made around reducing resonances in the disc, and I've yet to see real evidence for that either.

I haven't had a turntable for nearly 20 years now, so won't be researching this myself any time soon.

I own a vintage Oracle Delphi turntable. A threaded record spindle clamp comes with it as standard equipment. The platter matt might have some concavity built into it around the label area as well. It's a light weight piece of aluminum, so it doesn't add much mass, but once in place and tightened down, I can assure you it significantly reduces (but maybe not eliminate) any noticeable record warpage at the outer edge.

 

[Suffolkhifinut]

Since I was slapped by fellow ASR members for stating that subjectivism is a mental illness. I will not say it now. I'm just saying that guy is crazy! To admit publicly that changing the label direction on a fuse had any effect whatsoever, is astonishing. Who in their right mind would do that? So, I submit, he is nuts.

Who are you to lebal him nuts, see getting it the wrong way around makes a difference?

 

[Holmz]

I would gladly take the gold! Better than cheap copper wiring.

That was subtle. (Well done)

 

[SIY]

What is an “active shield”?

In the real world, it's a useful trick for high impedance lines. The shield is driven by a low impedance unity gain amp (buffer) replicating the inner conductor's signal. That way, the conductor-to-shield capacitance isn't being charged and discharged, limiting the HF response.

 

[raindance]

I own a vintage Oracle Delphi turntable. A threaded record spindle clamp comes with it as standard equipment. The platter matt might have some concavity built into it around the label area as well. It's a light weight piece of aluminum, so it doesn't add much mass, but once in place and tightened down, I can assure you it significantly reduces (but maybe not eliminate) any noticeable record warpage at the outer edge.

Ariston used to do the same thing. It worked well. You just had to set azimuth with the clamp in place.

 

[IPunchCholla]

In the real world, it's a useful trick for high impedance lines. The shield is driven by a low impedance unity gain amp (buffer) replicating the inner conductor's signal. That way, the conductor-to-shield capacitance isn't being charged and discharged, limiting the HF response.

Do you have any links to actual equipment tha uses it, I’m curious now as to what the device was.

 

[SIY]

Do you have any links to actual equipment tha uses it, I’m curious now as to what the device was.

Audio equipment? Not offhand, I do my best to stay out of that sort of useless stuff. I used driven shields for some scientific instrumentation, and I believe it's pretty standard for electrometers, remote capacitive sensing, and neural probes.

 

[DonR]

Do you have any links to actual equipment tha uses it, I’m curious now as to what the device was.

I have a Keithley 614 Electrometer with a driven guard option (6167).

The Keithley 6167 Guarded Adapter is an optional guarded adapter that is designed to be used with the models 602, 614, and 616 electrometers, and the models 220 and 224 current sources. This adapter is used to significantly reduce the effect of external input capacities and resistance by driving the inner shield of the triax cable guard potential. Circuit low is routed to the outer shield of the triax cable.

 

[sq225917]

I've only really ever seen the sme screw down clamp marginally flatten warp, their decks have a deep label recess and very mildly concave mat.

If you want em flat you need a peripheral ring weight.

 

[noiseangel]

That was subtle. (Well done)

I would too, that was my point.

 

[noiseangel]

Home made snake oil

 

[pinpoint_oxford]

Home made snake oil

I'm not sure they understand that "grounding" doesn't mean wire + dirt.