[bassboysam]

Now this gets interesting.  People say you can't generate enough power with solar panels for your home, but you could generate enough for your stereo(for my stereo at least).  And you could make everything out of rhodium plated platinum wires/switches, because it's all in your control (except for the sun, darn, might be too warm and bright for some).   Sounds like a business opportunity.

I'm sure you can tailor the sound to your liking by changing your latitude. Arizona sun would sound very different from say a Germany sun.

 

[Black Stuart]

As so much in audio, it makes me laugh that the very energy, electricity needed to power systems is almost totally neglected, no ignored and the idiots start moaning - there's nothing I can do, yes there is.
 
In the UK right now property is a crazy price, to give yourself totally clean power and a voltage that  will be + or - 1%, of 220 or 230V just invest in cheap deep cycle golf cart or more expensive sealed for life batteries and a pure sine wave inverter with automatic voltage regulation. The whole thing need'nt cost more than £1500 and that means that all your electrical equipment can receive clean regulated voltage with no threat of surges.
 
Then use your own personal choice of fuses. You could cheapskate and buy a BPS - balanced power supply but it cannot give the quality of the above and only for your sound system.
 
In the UK, so many idiots stay with the fused plugs when they can safely ditch this rubbish and use Shuko plugs and dis. blocks.

 

[BiggerHead]

But it's not totally neglected.  There is quite a bit of attention put into the DC regulation in the amps themselves. I don't think there is any practical limit to how well you can do this on the DC side.  The question is is it cheape(for the same sound of course)  to do some of it on the AC side? Isn't it a little silly to charge a dc battery, then make into AC, and then plug it into an AC/DC converter/regulator (inside your amp maybe)?  Isn't less more in audio?  Once you have a battery, why not skip the AC and use good DC-DC converters?  Ok you probably get some switching noise, but I guess that can be filtered too (and maybe a digital sine wave generator has that too).  Just get bigger capacitors.
 
 
I assume you charge your batteries when you're not listening to the stereo. 

 

[setamp]

I have found Alan Maher's fuse wraps to work quite well in my setup.  They improve even "audiophile" fuses.  The wraps can be a bit tricky as they add bulk to your fuse and create a tight fit in some fuse holders but I have found they work to reduce noise and improve micro dynamics.  They take some time to burn in - how this happens with a wrap i don't know, but my system went through clearly audible phases until settling down in about a week.  At $12.5 /wrap they may give you sufficient improvement that you can keep your standard fuses and be happy.  

 

[Edoardo93]

Does anyone knows the issue linked with the "going up in smoke" of the DarkVoice 336? is this a problem of many items or just a separate "case"?

 

[johnjen]

I just found this thread thanks to Big Poppa…

I too have been using SR20's and their Red fuses in my amps and dac.

I see them as a must have solution to the fuse as 'choke point' idea I adhere to.

The difference was quite remarkable, as I too originally figured a fuse, is a fuse, is a fuse…

This was yet another aspect of, and further motivation to continue, my pursuit of experimentation and investigation into ac power delivery tweaks.

I would also recommend using the WAQy chips on the fuses as well.
They work well together.

JJ

 

[BiggerHead]

Fuse is a choke point?  Are you saying fuses are too resistive? Cause too much voltage drop?  Enough to under-power the amp?

 

[johnjen]

In my research concerning what fuses are and do, I've found that it is not just about resistance.
There is a dynamic relationship between the internal resistance and the current flow capability as the fuse reacts to the changing amount of energy that passes thru the fuse.

The current doesn't pass thru in a continual flow, rather it passes thru in surges or pulses into our audio gear.
This is true for all diode bridge based power supplies.

This pulsing means that when the power supply calls for current to flow the fuse 'reacts' and tends to limit the amount of current it will allow thru at any given moment.

This is the 'choke point' where instead of allowing as much power to pass 'freely' into the transformer the energy tends to be restricted during the peak of the flow.

I'll go into more detail in a post in the cookbook thread in the future as it tends to get complicated fairly quickly.

JJ

 

[BiggerHead]

This is fully describable by the voltage drop across the fuse, and completely measureable and non magical and yes it's called resistance.  Even if you're saying a fuse is a non-linear resistor on short time scales, which is nonsense and also measureable,  that doesn't change the fact that it's the AC side of a DC regulator which is designed to stabilize its output against input fluctuations, fluctuations that come from a bunch more important things than this fuse.  Either you have a lousy power supply for your amp (AC/DC converter) and should spend the extra cash on that instead, or your fuse is SERIOUSLY underspecced, enough that's it's cause huge voltage drops, which by the way, would mean it should be blown.
 
I'm sure the rest of the religion is quite complicated. 

 

[BiggerHead]

 oh and never mind that so long as the amp is in class A mode, the power demand on it isn't even changing.

 

[johnjen]

I see…

JJ

 

[Speedskater]

  This is fully describable by the voltage drop across the fuse, and completely measureable and non magical and yes it's called resistance.  Even if you're saying a fuse is a non-linear resistor on short time scales, which is nonsense and also measureable,  that doesn't change the fact that it's the AC side of a DC regulator which is designed to stabilize its output against input fluctuations, fluctuations that come from a bunch more important things than this fuse.  Either you have a lousy power supply for your amp (AC/DC converter) and should spend the extra cash on that instead, or your fuse is SERIOUSLY underspecced, enough that's it's cause huge voltage drops, which by the way, would mean it should be blown.
I'm sure the rest of the religion is quite complicated. 

Not only is it measurable, Bob Cordell in his book "Designing Audio Power Amplifiers" did measure it. Turns out that it's 0.0033% THD at 20Hz and even smaller at higher frequencies.

 

[johnjen]

For those who would like to learn more about fuses, their design and how they respond to 'normal' power demands, here is a link to a few very interesting aspects of fuse performance.
These particular aspects of fuse design are found on pages 7 and 8 and 10 of the Littelfuse catalog.

http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_fuse_catalog.pdf.pdf

Resistance is the first aspect to pay attention to…
"RESISTANCE: The resistance of a fuse is usually an insignificant part of the total circuit resistance. Since the resistance of fractional amperage fuses can be several ohms, this fact should be considered when using them in low-voltage circuits. Actual values can be obtained by contacting Littelfuse.

Most fuses are manufactured from materials which have positive temperature coefficients, and, therefore, it is common to refer to cold resistance and hot resistance (voltage drop at rated current), with actual operation being somewhere in between.

Cold resistance is the resistance obtained using a measuring current of no more than 10% of the fuse’s nominal rated current. Values shown in this publication for cold resistance are nominal and representative. The factory should be consulted if this parameter is critical to the design analysis.

Hot resistance is the resistance calculated from the stabilized voltage drop across the fuse, with current equal to the nominal rated current flowing through it. Resistance data on all Littelfuse products are available on request. Fuses can be supplied to specified controlled resistance tolerances at additional cost."


But there is a measure of a fuses performance called I2t
To quote the section in the Littelfuse catalog…
"I2t is a measure of the energy required to melt the fusing element and is expressed as “Ampere Squared Seconds” (A2 Sec.)"

Here are the pertinent sections,
"DERIVATION OF NOMINAL MELTING I2t:
Laboratory tests are conducted on each fuse design to determine the amount of energy required to melt the fusing element. This energy is described as nominal melting I2t and is expressed as “Ampere Squared Seconds” (A2 Sec.).

A pulse of current is applied to the fuse, and a time measurement is taken for melting to occur. If melting does not occur within a short duration of about 8 milliseconds (0.008 seconds) or less, the level of pulse current is increased. This test procedure is repeated until melting of the fuse element is confined to within about 8 milliseconds.

The purpose of this procedure is to assure that the heat created has insufficient time to thermally conduct away from the fuse element. That is, all of the heat energy (I2t) is used, to cause melting. Once the measurements of current (I) and time (t) are determined, it is a simple matter to calculate melting I2t. When the melting phase reaches completion, an electrical arc occurs immediately prior to the “opening” of the fuse element.

Clearing I2t = Melting I2t + arcing I2t

The nominal I2t values given in this publication pertain to the melting phase portion of the “clearing” or “opening”. Alternatively the time can be measured at 10 times of the rated current and the I2t value is calculated like above."

&

"6. PULSES: The general term “pulses” is used in this context to describe the broad category of wave shapes referred to as “surge currents”, “start-up currents”, “inrush currents”, and “transients”. Electrical pulse conditions can vary considerably from one application to another. Different fuse constructions may not react the same to a given pulse condition. Electrical pulses produce thermal cycling and possible mechanical fatigue that could affect the life of the fuse. Initial or start-up pulses are normal for some applications and require the characteristic of a Slo-Blo® fuse. Slo-Blo® fuses incorporate a thermal delay design to enable them to survive normal start-up pulses and still provide protection against prolonged overloads. The start- up pulse should be defined and then compared to the time- current curve and I2t rating for the fuse. Application testing is recommended to establish the ability of the fuse design to withstand the pulse conditions.

Nominal melting I2t is a measure of the energy required to melt the fusing element and is expressed as “Ampere Squared Seconds” (A2 Sec.). This nominal melting I2t, and the energy it represents (within a time duration of 8 milliseconds [0.008 second] or less and 1 millisecond [0.001 second]or less for thin film fuses), is a value that is constant for each different fusing element. Because every fuse type and rating, as well as its corresponding part number, has a different fusing element, it is necessary to determine the I2t for each. This I2t value is a parameter of the fuse itself and is controlled by the element material and the configuration of the fuse element. In addition to selecting fuses on the basis of “Normal Operating Currents”, “Rerating”, and “Ambient Temperature” as discussed earlier, it is also necessary to apply the I2t design approach. This nominal melting I2t is not only a constant value for each fuse element design, but it is also independent of temperature and voltage. Most often, the nominal melting I2t method of fuse selection is applied to those applications in which the fuse must sustain large current pulses of a short duration. These high-energy currents are common in many applications and are critical to the design analysis."

And the question to ask is what is why is a pulse of current used for a measure of a fuse and more pointedly why is 8ms chosen as the time variable for this test?

JJ

 

[BiggerHead]

JJ I don't see your point.  First, there is nothing at all in this that I didn't already know (except for the 8ms specifically) and so I'm not sure what part you wish to make a big point about.
 
The text explains already why they try to burn the fuse fast.  If you burn it fast you know exactly how much energy it takes to burn it, because there is no time for the energy to dissipate.  Probably you can burn it in 8ms at  2 Amps squared or in 4ms at 4Amps squared, either way you put in 16 Amp^2 seconds * R Joules of energy, and I suspect so long as t is less than 8ms you'll get the same answer  whether t is 1 or 3 or 6 or 8, and that's the point.  I'd imagine they also test slower signals though.
 
What this really relates to indirectly is a temperature elevation.  The fixed energy added in some critical sub volume times the heat capacity of that subvolume equates a temperature change, which should relate to the melting or burning, or anyway failure point of the fuse. 
 
It is true that a fuse is more resistive than an average piece of wire, exactly because it needs to run near failure, but as the text said, a few ohms.  Even at 100 watts, at 120 v, that equates to a few volts of drop going into the amp, and so long as the amp is in class A mode it's a constant few volts.  The DC regulator should be able easily handle this. It's not like the output of the DC regulator rides up and down with the AC voltage.  There is a reason it's called a regulator.  It's buffered (capacitors) and hopefully a decent one uses internal voltage references (bandgap or whatever).  The AC mains just provide the power. 

 

[johnjen]

JJ I don't see your point.  First, there is nothing at all in this that I didn't already know (except for the 8ms specifically) and so I'm not sure what part you wish to make a big point about.

The text explains already why they try to burn the fuse fast.  If you burn it fast you know exactly how much energy it takes to burn it, because there is no time for the energy to dissipate.  Probably you can burn it in 8ms at  2 Amps squared or in 4ms at 4Amps squared, either way you put in 16 Amp^2 seconds * R Joules of energy, and I suspect so long as t is less than 8ms you'll get the same answer  whether t is 1 or 3 or 6 or 8, and that's the point.  I'd imagine they also test slower signals though.

What this really relates to indirectly is a temperature elevation.  The fixed energy added in some critical sub volume times the heat capacity of that subvolume equates a temperature change, which should relate to the melting or burning, or anyway failure point of the fuse. 

It is true that a fuse is more resistive than an average piece of wire, exactly because it needs to run near failure, but as the text said, a few ohms.  Even at 100 watts, at 120 v, that equates to a few volts of drop going into the amp, and so long as the amp is in class A mode it's a constant few volts.  The DC regulator should be able easily handle this. It's not like the output of the DC regulator rides up and down with the AC voltage.  There is a reason it's called a regulator.  It's buffered (capacitors) and hopefully a decent one uses internal voltage references (bandgap or whatever).  The AC mains just provide the power. 

You undoubtedly noticed I didn’t address my post to you specifically, rather it was aimed at anyone who wishes to know more about fuses and how a manufacturer designs and rates them for use.
And I do appreciate a constructive discussion and exchange of opinions about topics of mutual interest.

But let me be clear here, I see the function and purpose of fuses differently than you do.
And I don’t expect you to necessarily agree with me, because your understanding will be different than mine.
And in my mind that does not make either of us right nor wrong, as this can allow any of us to learn additional aspects which contribute to our understanding.
Or not, as is each individual’s desire.

Having said all of that, I figure most think of a fuse as just a protection device and little else. After all that is what they are used for.
But that, at least to what I have come to understand, is only a portion of their total function.

And the reason we are even discussing this is because of these ‘other’ functions, many of which are not measurable in the traditional sense, ie using test gear and measuring the standard parameters, (volts, ohms, etc.), that people do notice by using different fuses in their audio gear.
IOW this entire thread is an exchange of observations that centers upon these observable but difficult to measure changes that fuses make.

My research into fuses, a small portion of which I included into my post above, has led me to a more complete understanding of the total impact that improvements to the ac power delivery system makes upon our audio systems, of which fuses are but a part.
That is why I drew attention to the pulse of current and the 8ms time window as being significant.

So I understand why, as you put it, “I don't see your point”, because the rest of my understanding wasn’t presented and why I stated “I'll go into more detail in a post in the cookbook thread in the future as it tends to get complicated fairly quickly.”

And I can also understand why, as you state “The text explains already why they try to burn the fuse fast. If you burn it fast you know exactly how much energy it takes to burn it, because there is no time for the energy to dissipate”

But, again, your understanding isn’t mine.
Because the text didn’t explain to me “why they try to burn the fuse fast”, I came to that conclusion from an entirely different direction. One that is directly connected to that 8ms time duration used in the I^2t tests.

And your statement “What this really relates to indirectly is a temperature elevation” is another aspect where my understanding is different than yours, but probably not in the way you would think.

In my post that started this exchange I stated, “…I've found that it is not just about resistance. There is a dynamic relationship between the internal resistance and the current flow capability as the fuse reacts to the changing amount of energy that passes thru the fuse.”

To which you replied “This is fully describable by the voltage drop across the fuse, and completely measurable and non magical and yes it's called resistance.”

And to my mind if it were simply a matter of just resistance I doubt Anyone would hear differences between fuses.
But as I stated it’s a dynamic relationship of the fuse as it 'reacts’ to the changing requirements of power that passes thru the fuse, IN PULSES relating to those 8ms time windows, which is reflected in those and 8 pulses used in the I^2t testing.

Lastly let me say I don’t claim to know 'The Truth’, or all about this.
What I do claim is to have an understanding that makes sense to me, is supported by experiment and observation, some of which is observed by others as well.
And I am certainly open to bettering my understanding and enjoy pursuing this course of action at every turn.

JJ