"**Nonsense. There are several methods of implementing current limiting,
which do not impact severely on sound quality. If the current limiting
can be kept out of the global NFB loop, then the result can be very benign. "

They're all benign when not active. I am talking about when they are working actively limiting current. Maybe I didn't make that clear.

But if I did, and there is a scheme that will limit the current actively without that harsh distortion, show me. A model number will do now that with the internet I can usually get a print.

I saw one, in fact owned it. But it was not DC coupled and I don't remember the model. It was a Realistic integrated amp, maybe 40 WPC or something like that. Overload it and it seemed like the gain decreased, it didn't bark at you. But it also was not all that high end or high power.

"**That is the way high quality products do it. "

At the cost of market share of course. I agree though, just build it right and use like 12 amp speaker fuses.

HA, I remember Heathkit touted that their speaker fuses were in the feedback loop. Actually, the audiophile crowd kinda likes them.

On 30/03/2016 3:34 AM, wrote:
"**Nonsense. There are several methods of implementing current
limiting, which do not impact severely on sound quality. If the
current limiting can be kept out of the global NFB loop, then the
result can be very benign. "

They're all benign when not active. I am talking about when they are
working actively limiting current. Maybe I didn't make that clear.

**And I explained that, if the current limiting system can be kept out
of the NFB loop, then it's action can be benign.


But if I did, and there is a scheme that will limit the current
actively without that harsh distortion, show me. A model number will
do now that with the internet I can usually get a print.

**Do the analysis based on my description. I am aware of at least a
dozen products where the current limiting system is not contained within
the NFB loop and the result is gentle limiting. Schematics are not
generally available, AFAIK.


I saw one, in fact owned it. But it was not DC coupled and I don't
remember the model. It was a Realistic integrated amp, maybe 40 WPC
or something like that. Overload it and it seemed like the gain
decreased, it didn't bark at you. But it also was not all that high
end or high power.

**There you go. I know of one amp that used a simple lamp to limit
current through the output stage under overload.


"**That is the way high quality products do it."

At the cost of market share of course. I agree though, just build it
right and use like 12 amp speaker fuses.

**No high end amplifier uses non-linear resistors (aka: fuses) in series
with speakers. To do so, would be the antithesis of high fidelity.


HA, I remember Heathkit touted that their speaker fuses were in the
feedback loop. Actually, the audiophile crowd kinda likes them.


**Not me. Fuses should be there to prevent fires. Nothing more.



--
Trevor Wilson
www.rageaudio.com.au

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On Tuesday, March 29, 2016 at 4:00:24 PM UTC-4, Trevor Wilson wrote:

**No high end amplifier uses non-linear resistors (aka: fuses) in series
with speakers. To do so, would be the antithesis of high fidelity.

Please explain with other than anecdotal information. This reads suspiciously like advocating high-cost interconnects, line cords, and speaker wires....


Peter Wieck
Melrose Park, PA

On 30/03/2016 9:18 AM, wrote:
On Tuesday, March 29, 2016 at 4:00:24 PM UTC-4, Trevor Wilson wrote:

**No high end amplifier uses non-linear resistors (aka: fuses) in series
with speakers. To do so, would be the antithesis of high fidelity.

Please explain with other than anecdotal information. This reads suspiciously like advocating high-cost interconnects, line cords, and speaker wires....


**Now you're being silly. Measure a fuse sometime. The resistance
increases, as current increases. It acts as a non-linear resistor. The
ONLY place for a fuse is before filter capacitors in an amplifier. In
the DC lines, or the speaker lines, fuses introduce distortion and
should not be used. This is electronics 101.

For the record:

* People using fancy power leads are deluded. The best power leads are,
of course, old style captive ones. IEC connectors are convenient and
stupid. They allow consumers to be conned into changing power leads
needlessly.
* People using *LOW INDUCTANCE*, *LOW RESISTANCE* speaker cables may
not, necessarily, be deluded. Again: Electronics 101.

Here are a couple of examples why such speaker cables may be useful:

http://www.rageaudio.com.au/modules/...05452_accu.jpg
http://www.rageaudio.com.au/modules/...656_kappa9.jpg


Never throw the baby out with the bathwater. Electronics 101.


--
Trevor Wilson
www.rageaudio.com.au

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On 25/03/2016 9:48 PM, Mark Zacharias wrote:
How is it a grown man cannot understand the concept of keeping two wires
separate?

Fixed a Yamaha RX-A2010 with a blown channel back in December.

Under warranty.

Big job.

Cautioned him on speaker hook-ups, gave him our hand-out sheet
explaining speaker connections,
which also contains explicit warnings about shorting wires etc.

Nevertheless he brought it back this week with the same channel blown
again.

It was all I could do not to just go off on the guy. He admitted fooling
around with the wires while the unit was powered up, and that the wires
had crossed. Exactly the sort of thing I had "educated" him about.

****ing idiot. Lucky for him Yamaha is covering it again, and we needed
the work anyway.

**** for brains god damn idiot. I knew better that this when I was
sixteen ****ing years old!

I'm reminded of Chevy Chase's rant in Christmas Vacation...


**I have only done once or twice, but with a couple of recalcitrant
clients, I have installed Polyswitches into their equipment. Mostly
speakers, but sometimes amplifiers.


--
Trevor Wilson
www.rageaudio.com.au

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On Tuesday, March 29, 2016 at 6:58:21 PM UTC-4, Trevor Wilson wrote:


**Now you're being silly. Measure a fuse sometime. The resistance
increases, as current increases. It acts as a non-linear resistor. The
ONLY place for a fuse is before filter capacitors in an amplifier. In
the DC lines, or the speaker lines, fuses introduce distortion and
should not be used. This is electronics 101.

Silver-link fuses using an eutectic formula add negligible resistance within their ratings. Nor are they cheap. As you well know, silver is the closest thing to a super-conductor at any reasonable operating temperature as exists in nature, much better than copper (or gold), and so such fuses ought to be considered.

Example: I keep speakers from a current manufacturer that would cost me well over US$7,000 to replace today. A few bucks on fuses to protect this investment is well worth it. That I researched dual-element silver-bearing fuses to minimize any downside from adding such a device makes the choice both worth it and (probably) wise. A defective amp is not likely to gradually ramp up into the speakers, it is likely to surge - at least in my experience. So, I can run the fuse very close to the overall speaker rating letting the dual-element section handle high musical peaks without sacrificing (much) protection.

Keeping in mind that as you suggest, low-resistance speaker connections are a 'good' thing, I use #12 fine-stranded (19 strands) THHN wire for speaker leads, spun in a drill to reduce capacitance does well for short runs and is remarkably cheap at ~US$0.27/foot (both stands included).

But, a fuse on a $3,500 speaker?

Wouldn't you?

Peter Wieck
Melrose Park, PA


For the record:

* People using fancy power leads are deluded. The best power leads are,
of course, old style captive ones. IEC connectors are convenient and
stupid. They allow consumers to be conned into changing power leads
needlessly.
* People using *LOW INDUCTANCE*, *LOW RESISTANCE* speaker cables may
not, necessarily, be deluded. Again: Electronics 101.

On 31/03/2016 3:30 AM, wrote:
On Tuesday, March 29, 2016 at 6:58:21 PM UTC-4, Trevor Wilson wrote:


**Now you're being silly. Measure a fuse sometime. The resistance
increases, as current increases. It acts as a non-linear resistor.
The ONLY place for a fuse is before filter capacitors in an
amplifier. In the DC lines, or the speaker lines, fuses introduce
distortion and should not be used. This is electronics 101.

Silver-link fuses using an eutectic formula add negligible resistance
within their ratings. Nor are they cheap. As you well know, silver is
the closest thing to a super-conductor at any reasonable operating
temperature as exists in nature, much better than copper (or gold),
and so such fuses ought to be considered.

**Perhaps.


Example: I keep speakers from a current manufacturer that would cost
me well over US$7,000 to replace today. A few bucks on fuses to
protect this investment is well worth it. That I researched
dual-element silver-bearing fuses to minimize any downside from
adding such a device makes the choice both worth it and (probably)
wise. A defective amp is not likely to gradually ramp up into the
speakers, it is likely to surge - at least in my experience. So, I
can run the fuse very close to the overall speaker rating letting the
dual-element section handle high musical peaks without sacrificing
(much) protection.

Keeping in mind that as you suggest, low-resistance speaker
connections are a 'good' thing, I use #12 fine-stranded (19 strands)
THHN wire for speaker leads, spun in a drill to reduce capacitance
does well for short runs and is remarkably cheap at ~US$0.27/foot
(both stands included).

But, a fuse on a $3,500 speaker?

Wouldn't you?


**I am 62 years old. I've been listening a sound system since I built my
first one at age 17. In my 20s, I purchased my first home and proceeded
to assemble a sound system to please myself and my friends at various
parties. It also drove my neighbours a little nuts. This is the
amplifier I used to drive my KEF transimssion lines (rated at 50 Watts)
at many, many drunken parties:

http://audio-database.com/MARANTZ/amp/model500-e.html

I still own the best, but no longer use it. I certainly don't operate my
sound system at the kinds of levels I once did. I also use vastly more
sophisticated amplification nowadays (soft clipping, soft current
limiting, etc).

In my entire 45 years of listening, I only ever damaged one of the B139
drivers. The reason the driver failed was due to poor assembly at the
KEF factory. So, no. I would not put a fuse on a speaker of MINE. I
don't damage speakers. For all intents, I never have. For customers, the
situation is different. For headbangers, I will certainly suggest the
use of polyswitches or fuses, as the safety outweighs any potential
downside. I would certainly not install a fuse or Polyswitch in any high
end system, unless the client and I decided it was prudent. I did so
with these speakers, after long consultation with a client however:

http://elac.ro/elac%20x-jet%203.jpg (exploded diagram of the mid/HF driver)

The HF element (equivalent to a Heil unit) had failed, after his
children accessed his hi fi) was not repairable. A new driver had to be
sourced at almost AUS$1,000.00.

So yes, I fitted Polyswitches to protect the drivers.


--
Trevor Wilson
www.rageaudio.com.au

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wrote:
On Tuesday, March 29, 2016 at 6:58:21 PM UTC-4, Trevor Wilson wrote:


**Now you're being silly. Measure a fuse sometime. The resistance
increases, as current increases. It acts as a non-linear resistor. The
ONLY place for a fuse is before filter capacitors in an amplifier. In
the DC lines, or the speaker lines, fuses introduce distortion and
should not be used. This is electronics 101.

Silver-link fuses using an eutectic formula add negligible resistance within their ratings. Nor are they cheap. As you well know, silver is the closest thing to a super-conductor at any reasonable operating temperature as exists in nature, much better than copper (or gold), and so such fuses ought to be considered.

powerline expulsion fuses use silver wire as the element. I was told
nothing is as reliable during a factory tour.

" wrote:

On Sunday, March 27, 2016 at 5:03:32 PM UTC-4, Michael Terrell wrote:
" wrote:

N_Cook wrote:

I have a customer who keeps breaking things, often fatally, because he
picks up the nearest wallwart, having mislaid the original one, because
it looks the same size black lump and the connector pushes in, so it
must be ok .

Once upon a time, there was movement to color-code and size-code these things... It never quite took.


Have you seen these adapters?

http://www.ebay.com/itm/171829811403

I have. Sadly, it was the south end where the color-coding never took, not the north end.


I bought them for the workbench, i really don't care that they are
color coded like other adapters I have that are the wrong voltage. A
cable connected to a 0-20V 3A HP 6253A power supply on the bench lets me
power almost any DC powered device to see if it works, or to repair the
ones that don't. No need to modify an existing supply, just to see if
something works.

wrote:


Silver-link fuses using an eutectic formula add negligible resistance
within their ratings. Nor are they cheap. As you well know, silver is
the closest thing to a super-conductor at any reasonable operating
temperature as exists in nature, much better than copper (or gold),
and so such fuses ought to be considered.


** Silver is only 6% more conductive than copper, has the same tempco of resistance and a lower melting point. A silver or copper wire fuse increases its resistance by at least 4 times before opening.

OTOH, a tin fuse with a far lower melting point than either, increases in resistance by less than double before opening. Often made as a flat strip with a neck in the middle, they are semi slow-blow too.

Fine for loudspeakers.


..... Phil

Trevor Wilson wrote:



**Now you're being silly. Measure a fuse sometime. The resistance
increases, as current increases. It acts as a non-linear resistor. The
ONLY place for a fuse is before filter capacitors in an amplifier. In
the DC lines, or the speaker lines, fuses introduce distortion ...


** On the DC lines there is always lots of 100Hz ripple AND *half wave* signal voltage imposed on the wiring and filter cap ESR - which the PSRR of the amp rejects anyhow.


This is electronics 101.


** Only on planet Wilson.


..... Phil