How to measure current limiting?

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dBe

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Re: How to measure current limiting?
« Reply #20 on: 20 May 2010, 05:11 am »
Indeed, this will cause minimal current limiting in a conditioner. The flip side is that one can't produce more than 6db/octave (first order) noise attenuation, starting that filtration far up into the noise spectrum and is incapable of providing any material noise isolation between outlets.

I was wondering how you could claim isolated circuits in your Busss, but now I see how multiple RFI cores could provide measurable isolation, albeit over a narrow portion of the noise spectrum.

There are vendors who feel a material amount of series inductance (what you're call current limiting  :wink:) is a good thing, like Audience, Running Springs,mysef and others, and their customers use them quite happily on many different power amplifiers, nor do they complain of limited dynamics. The series inductance/shunt capacitance filter allows stronger filtering (>=12db/oct), starting significantly lower in the noise spectrum. No doubt, there are some amplifiers that work better with capacitive, parallel filters, or none at all. I've yet to hear any mains powered switching amp that was listenable without a series inductance/shunt capacitance (or balanced) power conditioner feeding it.

FWIW,
Paul
It is possible to affect a rolloff without series inductance that is in excess of 6dB/octave.  Figuring out how is the Majik part.   :D

The filtration of my units is very broad band. 

In every direct comparison that my clients have told me of (me, too, but that reflects my bias) with of any of my products to other units on the market reveals the BUSSes to be more dynamic than the comparison units.  They are more dynamic than a direct connection to the wall.  Don't believe me, ask my clients.

I agree that switching amps can be very difficult.  A lot of the problems with them are modulation effects induced by noise components on the power supply output not mitigated by the PS itself.  I prefer an after filter in series with the PS outputs in those types of units, too.  Groundplane pollution is nasty in switchers.

At the risk of being politically incorrect (you know: PI) there is more way to skin a small, furry animal of your choice.

Dave

dBe

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Re: How to measure current limiting?
« Reply #21 on: 20 May 2010, 05:25 am »
jtwrace, dBe, Occam and everyone else interested in power filters (not surge suppressors)... The best way to do power filtering is this: For low level audio components such as CD players, DACs, preamplifiers, phono preamplifiers, anything video/digital, etc. the best method is to use an isolation transformer per outlet (per component) followed by a parallel capacitive AC line filter (after the isolation transformer).

For power amplifiers, DO NOT USE isolation transformers (unless you want to slow down the slew rate transient response of your amplifier). Just use a parallel capacitive filter (not series inductor - unless you want to slow down the slew rate transient response of your amplifier). That's it! Simple as that!

This is the proper way of doing power filtering for audio and this is the BEST way. Period. I just took the myth out of power filtering for all of you. And this is simple enough for anyone to construct themselves. No need to wonder about any magical PI Audio, PS Audio, Transparent, MIT, etc.

For surge suppressors you have only 2 options: MOV based (everything else), or Series Mode (I.E. Zero Surge, Brickwall, SurgeX, Torus). Both have their weaknesses and both have their strengths. NEITHER is better than the other. BOTH have negative effects on power amplifiers. BOTH are current limiting.

Thread closed.
Whatever.

Oh, yeah - can you say gas discharge tubes?  High speed switching diverters?

Who are you to close the thread, anyway?

 :?

Dave

jtwrace

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Re: How to measure current limiting?
« Reply #22 on: 20 May 2010, 11:16 am »
Ok.  So I think I just learned something.

To get back to my original post though, how does one measure the current limiting effect (if any) on the Zero Surge units? 

The answer "it does, I looked at the schematic" isn't scientific enough for me.  I need data!!!  That's the engineering approach IMO.

Anyone want to do it?  I'll send you a unit.   :)

NagysAudio

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Re: How to measure current limiting?
« Reply #23 on: 20 May 2010, 08:10 pm »
jtwrace - Who in their right mind would embark on this nonsensical time consuming project? It's OBVIOUS that those circuits are current limiting, OBVIOUS. To actually test the Zero Surge unit and publish the data in a fashion that YOU would understand is an involving, tedious, time consuming project. However, I will do it for you! I even have a Zero Surge unit myself, so no need for you to send it to me. I will however need to charge you for my time, $90 per hour for however long it takes to complete the project. If you're seriously interested, I can give you a better estimate in how long something like this would take. I will need a 100% up front payment before I even touch anything.

mfsoa

Re: How to measure current limiting?
« Reply #24 on: 20 May 2010, 08:40 pm »
Paul and Dave,
When you discuss the use of conditioners on switching amps, are you refering to those that use switching power supplies or are the linear power supply Class D amps in the same camp too?

Thanks

-Mike

jtwrace

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Re: How to measure current limiting?
« Reply #25 on: 20 May 2010, 09:32 pm »
jtwrace - Who in their right mind would embark on this nonsensical time consuming project? It's OBVIOUS that those circuits are current limiting, OBVIOUS. To actually test the Zero Surge unit and publish the data in a fashion that YOU would understand is an involving, tedious, time consuming project. However, I will do it for you! I even have a Zero Surge unit myself, so no need for you to send it to me. I will however need to charge you for my time, $90 per hour for however long it takes to complete the project. If you're seriously interested, I can give you a better estimate in how long something like this would take. I will need a 100% up front payment before I even touch anything.

I greatly appreciate the offer.  I would have no issue with spending the money but I think this test is geared more for someone who will not be biased in any way and someone who is in the field of power.  Not making cables.


pjchappy

Re: How to measure current limiting?
« Reply #26 on: 20 May 2010, 09:43 pm »
Removed personal attacks, etc.

Keep things on topic. . .and please stop the pissing contest.


Paul

jtwrace

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Re: How to measure current limiting?
« Reply #27 on: 21 May 2010, 03:33 pm »
Guess not. 

sts9fan

Re: How to measure current limiting?
« Reply #28 on: 21 May 2010, 03:44 pm »
This thread has two strikes FYI

jtwrace

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Re: How to measure current limiting?
« Reply #29 on: 21 May 2010, 03:55 pm »
This thread has two strikes FYI

 :scratch:  Oh Ok.  I didn't know.  At least it has something. 

dBe

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Re: How to measure current limiting?
« Reply #30 on: 21 May 2010, 03:57 pm »
Paul and Dave,
When you discuss the use of conditioners on switching amps, are you refering to those that use switching power supplies or are the linear power supply Class D amps in the same camp too?

Thanks

-Mike
Mike, it is the switching power supplies that break my head.  Class D (with a linear supplies) doesn't sound all "switchy, twitchy" like anything with a switching power supply does.  The worst offenders are CD/DVD/Bluray players with switchers, at least to me.  I can't think of a worse place to have RFI and EMI running around than in a piece of gear as fragile electrically than digital gear.  for digital to sound its' best, the power has to be pristine, IMNSHO.

Dave

dBe

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Re: How to measure current limiting?
« Reply #31 on: 21 May 2010, 04:00 pm »
This thread has two strikes FYI
Sorry for the OT.  Mike asked and I answered.  My bad.  Divergence as a way of life, I reckon.   :dunno:

Dave

skunark

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Re: How to measure current limiting?
« Reply #32 on: 21 May 2010, 05:56 pm »
jtwrace,

Wouldn't a cheap clamp style amp meter be enough here?  I assume you don't need to test the limits of the components but more or less if the current is limited when plugged into the PLC vs the wall.



jtwrace

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Re: How to measure current limiting?
« Reply #33 on: 21 May 2010, 06:01 pm »
jtwrace,

Wouldn't a cheap clamp style amp meter be enough here?  I assume you don't need to test the limits of the components but more or less if the current is limited when plugged into the PLC vs the wall.

I thought the same thing but according to this thread, no.

sts9fan

Re: How to measure current limiting?
« Reply #34 on: 21 May 2010, 06:32 pm »
Quote
Sorry for the OT.  Mike asked and I answered.  My bad.  Divergence as a way of life, I reckon.   

Dave

You had nothing to do with it.  I got no beef with off topic stuff in a thread like this. 

dBe

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Re: How to measure current limiting?
« Reply #35 on: 21 May 2010, 08:48 pm »
You had nothing to do with it.  I got no beef with off topic stuff in a thread like this.
Cool.   8)  Thanks.

Dave

skunark

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Re: How to measure current limiting?
« Reply #36 on: 22 May 2010, 12:04 am »
I thought the same thing but according to this thread, no.

If there is a will there is a way:
http://www.cromwell-intl.com/technical/current-box.html

With that said, you can try this.. Perhaps an easier thing to do is make your own super heavy duty extension cable with the hot available.   There are also items for your electric meter that would do this as well but you need to understand what is plugged in taking the measurements...I would guess you might loose some accuracy as well..   

NagysAudio

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Re: How to measure current limiting?
« Reply #37 on: 22 May 2010, 04:00 pm »
jtwrace - Connect the amp directly to the wall, connect the oscilloscope to the output of the amp. See how it responds with square wave, extremely short impulse signals, very high frequency signals, etc.

Now connect the amp to the Zero Surge unit and repeat the above. Compare the results.

Dan Banquer

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Re: How to measure current limiting?
« Reply #38 on: 25 May 2010, 07:28 pm »
" Groundplane pollution is nasty in switchers."

Bruno Putzeys has talked about this extensively for switching amps and linear design, and I agree with him 100%. The refusal for many people to correctly lay out a PC board is prevalent in this business.
No amount of filtering will really correct for this, and the best you can hope for is a band aid.

Good luck

ctviggen

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Re: How to measure current limiting?
« Reply #39 on: 25 May 2010, 09:46 pm »
jtwrace - Connect the amp directly to the wall, connect the oscilloscope to the output of the amp. See how it responds with square wave, extremely short impulse signals, very high frequency signals, etc.

Now connect the amp to the Zero Surge unit and repeat the above. Compare the results.

In my previous life as an EE, I used to test a variety of systems (analog and digital).  What you've proposed seems very easy, but in reality it's not nearly as easy as it appears.

Say you use a square wave.  Then you need to have both the input and output on a single screen at one time and then also print it.  You should likely print both blown up (short time frame) and long (long time frame) versions.

Next, you test with the surge protector in place and take the previous measurements.  Now comes the hard part:  What do the differences mean? 

The first problem is that the test is artificial.  Music isn't square waves.  You're trying to simulate some type of quick response to, say, a hit of a cymbal.  But unless you know what a symbol hit looks like in real life (in the time domain and perhaps the frequency domain), then the input signal might not be a realistic representation of what happens in real life, and therefore the test would be invalid. 

The second problem is that there is always error in testing.  Is the result within the error?  How do you even determine that? 

Developing a test of this will not be a simplistic endeavor and chances are that your initial test will be a complete failure.