An argument for fuses and maybe power cables in power amplifier

There are a lot of discussion about fuse but I don't remember a thread that include

an actual circuit.

The circuit below is called a rectifier which converts AC voltage from the wall to DC voltage that feeds to audio power amplifier.  All if not most power audio amplifier uses this topology.  Some have bigger transformer, some have more capacitors, some have higher voltage output but most are more or less the same.  Audio amplifer uses a lot of current so they don't use a regular which may even degrade the supply, therefore most will just use what you see below as a rectifier circuit.

You can see from the circuit the current comes from the wall, the AC source far left, to the fuse, F1 5A upper left, go through the transformer then to the diode rectifier, D1 D2 D3 D4, then finally to the 25+/- supply source which then will feed to the power audio amplifier.  

So you can see the fuse is clearly in the signal path.

As for the power cable, it is harder to understand.  Most power cable are already  beefy enough to handle the current so having an even beefier cable will help is something that needs further reasoning.



It's not that regulators degrade sound, it's that high current regulators get very expensive.  Krell has attempted this, essentially an amp inside an amp, Sanders Magtech gets close.  Class H amplifiers are, loosely, similar.


Everything is in the path, but not everything matters.  As for power cables, I do like to use inexpensive but shielded cables to minimize the possibility of EMI/RFI noise being picked up after my power conditioner.  My integrated includes a large ferrite bead around the incoming power line which in my mind will do far more than anything that can be done by a fuse.


                                                            A rewind:
        Anyone needing a rationale for experimenting with new cables in their system and/or feeling dissuaded by the Church of Denyin'tology's antiquated electrical doctrines: take heart!

        Many new electrical facts have been established in the past 100 years, that support audible differences, between various cables, fuses, etc.

         I couldn't find anything like, "Updated Electrical Theory For Idiots", but- did manage to find something resembling a cartoon, that even a child could follow.  It neither mentions AC/sinusoidal waves in wires, nor does it go into the photon propagation of electromagnetic waves.   It does, however, emphasize/demonstrate how Electrical Theory has progressed, since the 1800s:


        These next two presuppose a certain amount of knowledge, in the field of modern Electrical Theory.    Click, "more" in the first link's third answer, to get its entirety.    Note how it mentions the OLD, "... commonly held misconception that the flow of electricity through a wire resembles a tube filled with ping pong balls...", to which the Denyin'tologists fervently adhere:


        It's an established (measured) fact that an electromagnetic wave's propagation and speed, are dependent on the materials, of which the transmission line (cable) are made (ie: Dielectric Constant/permittivity).     The better (lower) the Dielectric Constant the better the flow and the longer it takes for that material to become polarized.     One reason anything that comprises an RLC circuit (ie: capacitors, cables, PC boards), takes time to, "form", or, "break/burn-in".*      

          *Some things that make the Denyin'tologists apoplectic:
        The conductor acts as a waveguide:

          Even the most inane (regarding the Sciences) must admit; braiding and twisting wires eliminates/reduces EMI interference.              
          That must lend credence to various cable geometries.

          That better dielectrics enhance the propagation of electromagnetic waves (ie: your music signal), lends the same credence to choosing cables with better materials (ie: Polypropylene, Teflon, air, etc).

           Of course: anything the Church of Denyin'tology's popes can't fathom, they'll summarily dismiss.
         As simple a device as a fuse is: it still carries a sinusoidal signal/voltage, ALWAYS from source to load.
                                                 NOT back and forth!
         Also (as mentioned above): any fuse acts as an RLC circuit, the 'C' of which will be determined by properties of its wave guide's/ conductor's surroundings (ie: glass, air, bee's wax, ceramic, end cap materials, etc).
          Any commonly drawn wire will exhibit a chevron pattern in its crystal lattice, so: why not "directionality" and why OHNO Continuous Cast, single crystal wire sounds better, to so many?
                   Stated above are scientifically tested, measured and proven facts. 
                                  There is no "contest", or "dispute" involved.
         The OP mentions Maxwell, but: obviously they have no understanding of his theory and possible ramifications as regards the above.
          Anyone that feels compelled to harp on not hearing any differences, is obviously too obtuse to understand the term "variables" (as frequently mentioned) and worthy of disregard.
          My only goal in these threads has ever been to encourage those with a mind to experiment with their systems, based on the latest (20th/21st Century's) findings of ACTUAL Physics/science and ignore the Cargo Cult's incessant runway building (objections, convolutions, deflections and obfuscations).
                                                       Happy listening!

     Back in March 2022: a thread about power cords and break/burn-in was started.

     I hate to type, so: I'm going to copy/paste some of my speculations.

     That a highly complex musical signal, MIGHT affect Poynting vectors and signal speeds*, in interconnects, in a much more profound manner than a simple AC (ie: a fixed 60/50 Hz) signal, in a PC, seems likely (at least) to me, as; in EVERY formula regarding *those two, a signal's frequency (frequencies) always factors in greatly.

     Further: the above and what I'll c/p (seems to me) lends credence to how the application of a stronger, DC voltage/field, outside a dielectric (ala Synergistic MPC and Audioquest DBS systems), might stabilize those vectors and signal speeds, PERHAPS eliminating some time smear and, "burn-in". 


5,456 posts

03-31-2022 at 12:13am 



      Bear with me a minute, in my folly, far as a possibility on why a power cord might make a difference.

      Based on some of the theories on how electricity works, simplified:

      The conductor acts as a waveguide for the signal/voltage.

      Within the conductor: when excited by an AC current, electrons oscillate, generating photons/electromagnetic waves that travel, always from the source, to the load.

       Keep in mind: all signals (ie: music, AC) are sinusoidal  waves

       Those photons/electromagnetic waves travel through and outside the dielectric, which (according to it's permittivity/Poynting vectors) will have various effects on those waves.    One of the most obvious is the dielectric's effect on the speed of the signal.

      The better designers of printed circuit boards, even take the above into account, when choosing materials for their products.

       I posted a link on the first page that included data on the manufacture of semiconductor chips and what was observed when materials were cryo'd, during the process.     Short version: better contact/lowered resistance between layers.

          Under the scanning microscope: much smoother surfaces observed.

       I would hope, by now, it's a given that various cable constructions, twists, braids, etc, can make for a cleaner transmission of signals (ie: Litz, etc).            

        Just seems to me (a hypothesis): given the above (some theories and some things established/measured/proven), it's not a big stretch to believe a power cord, built of the best conductor (ie: Ohno CC silver*), wrapped in a very low dielectric coefficient dielectric (ie: Teflon), cryo'd for the smoothest transfer of those photons/magnetic waves and twisted in some crazy way, might not smooth out some of perturbations/noise, from the crap an AC waveform had to go through, back to it's generator.  (run-on, much?)

         *Many mention NOT noticing an improvement with upgraded PCs, when owning Pass Labs gear (KUDOS to Nelson).   Of MUCH interest is the fact that Frank Dickens, the owner of Silent Source cables is basically on staff with Pass and: they voice their equipment with his cables and power cords, made largely with Ohno CC metals.

       I haven't tested this, actually comparing two circuits, but: it wouldn't surprise me, if a power supply that used a choke, would be less affected by a better power cord, as the former can eliminate a lot of the high freq garbage, etc, that's either created by, or makes it through all the big converting/filtering stuff, in the power supply, before.

       Never thought about PCs before the good stuff hit the market, but: the Physics/QED made sense.

            I tried 'em, I like 'em and the science makes my head feel better.

                              Don't care WHAT it does to anyone else's!



5,456 posts

03-31-2022 at 12:27am 


     OH, and: it takes some time for the dielectric to form, take a charge, polarize, or however one chooses to define the process, when a dielectric is subjected to electromagnetic waves, which affects the Poynting vectors, measurably/predictably.

                                            The lower the material’s dielectric constant: the longer that takes.

                                                              PC (interconnect/etc)  burn-in?    Maybe?

                                                                                         Happy listening! 


             I'm not disagreeing with any postings, prior to mine, in this thread.

             ie: everything in the power supply/AC source is in the signal path*.

       *In every gain stage: DC power supply voltage is modulated/magnified, as directed by the musical signal, via the circuit designer's gain device(s), be they SS or valve.

                 A cleaner/more pure DC voltage = more faithful musical output.

I can remember reading an audio equipment circuit designer saying a power cord is not an extension of the branch circuit wiring in the wall but rather an extension of the primary winding leads of the power transformer.

Fuse. The purpose is to provide short circuit/overload protection.

A good fuse clip will provide good surface area and good fuse clip to fuse contact pressure. Poor contact pressure can cause series micro arcing creating ac RFI noise into the primary winding of the transformer. My understanding the frequency of the series arcing will pass onto the secondary winding(s) of the transformer. Using the simple drawing supplied by the OP you will notice the center tap of the secondary winding is the B- of the power supply, signal ground, and in some fashion connected to the chassis of the equipment. (Note: I am not an EE or audio equipment designer.)

After market fuse. No opinion one way or the other. Never tried them. A lot of audiophiles who have and use them, swear by them. Their listening experiences works for me. ( I just got this thing about is the fuse tested and Listed by UL or some other NRLT recognized third party testing laboratory?)

After market power cords: The majority of actual listening tests I’ve done has been connected to digital equipment. Tried some that degraded the sound and others that improved the sound. Some noticeably improved the sound, at least to my ears... And that’s all that really matters to me.

The why after market power cords make a difference? Lots of theory... Actual testing using testing equipment? Just my ears. I don’t watch oscilloscope screens or listen to test tones. Just music using my ears. YMMV



The why after market power cords make a difference?  Lots of theory... Actual testing using testing equipment? Just my ears. I don’t watch oscilloscope screens or listen to test tones.  Just music, using my ears. 

                                       And: that's ALL that matters!



      Some people just don't seem to understand; there are a plethora of variables.

                                                  Happy listening!

Linear power supply is really a primitive switcher operating at 120Hz.  Current is drawn from the mains in narrow spikes of high amplitude, that become wider when load increases.  In addition rectifiers become reverse polarized at the peak of the voltage conducting for a moment in the opposite direction creating narrow spike that couples to any, even smallest inductance in the circuit.  

The fact that current is drawn in narrow spikes has serious consequences.  Transformer has to be larger than one with resistive load, because higher rms to average current ratio is causing bigger losses in windings, while high frequency content increases core losses (eddy currents, hysteresis).  These narrow current spikes of high amplitude travel thru fuse and power cable making things very complex.  

As for the power delivery, it should be obvious from the definition of electric current (flow of electric charge), that the exactly same amount of electric charge leaving one leg of power supply comes back in another.  Power has to be delivered different way.  Current in the wire creates magnetic field around conductor while presence of load makes voltage drop - an electric filed.  These fields cross each other like X-Y axis while Z axis perpendicular to them shows direction of the power delivery (Poynting vector).  Power is absorbed by the load from electromagnetic wave.

To improve linear power supply circuit I would look for “soft” rectifier (like Hexfred) , that, after conducting for a moment reverse polarized, don’t snap back too fast (wider spikes are better).  I would also look for low inductance electrolytic capacitors, like “slit foil” type.  0.1uF capacitor in parallel helps, but with large inductance of main capacitors can create parallel resonance circuit and possible ringing.


@rodman99999 .....*slow clapping* { it's late....the cats are asleep}

Thenk you, Dr. Whiplash..... ;)

Some people just don't seem to understand; there are a plethora of variables.

....and, given that bit of clarity; 'X' = Infinity, macro v. mega, everywhere in everything...even in the 'nothing' of space....

   They know
 What is What
They Don't Know
   What is What
     It just suks

Back to the Theories! *G*👍

Actually, rodman9x5, that was actually entertaining.....

@asvjerry -

   They know
 What is What
They Don't Know
   What is What
     It just suks

            Funny!     AND: a snowflake had me deleted, just recently, for saying, "it's like teaching a box of rocks, to sort your socks!", in their exhausting, er.. I mean: exhaustive thread.

                                   Put another way:  

            The problem with naysayers isn't that they're ignorant.

             Rather: it's they're knowing so much that's incorrect*.

                            *The very heart of Dunning-Kruger

                                          Happy listening!


                              ps: The nines are exponential.   


@asvjerry -

                                      OH, and:

Thenk you, Dr. Whiplash..... ;)

                   Yu're welcome, I thynk?    ¯\_(ツ)_/¯

"DeeeKay, have it Your Way!"

Ah...ASCII Art....been awhile... I remember when we used to chisel that into the nooks 'n crannies to confuse the archaic-ologists and please the tinfoil hat crowd....

Now?  ....just type...*sigh*....

Better laughs to chisel in "Don't move this block!" on a face; on the opposite side, "See? Told you....'nuthin'."  just before it would tip over onto them....

PP.....Pyramid Pranked.
​​Y​​​eah, @rodman99999....the good old days....

"Exponentially speaking typing, you must be pretty high by now... ;) 

BTW, Dr. Whiplash was a 'proprietor' of  a "Miracule! Liniment! that will cure Everything from muscle ache and pulls, gout, headache, heartache, ..."

I've got nearly enough line power cords to nearly knit a net with pool cues (some smart*ss wrote a book on the subject....honest! )
Given all the high-level attention given to an item that spends a lot of its' time on floors for the most part.....

As noted: 


if it's not for such as this...for me, perhaps you, with this little ditty from the DB's....


                                               why? of your days, J



As an electronic design engineer I will say that if the power cord and fuse makes a difference in the amplifiers performance then the amplifier has not been designed with the proper margin.  If designed correctly the AC to DC conversion in the amplifier should have margin for line voltage variation, energy storage (caps) and so-on.  Surge protection is another must have.  

^^^ On the other hand, on a poorly design AC-DC conversion amplifier, it will be the bottle neck therefore a power cable or fuse would not make a difference.

For example on a cheap Japanese receiver, I doubt the fuse or power cable would make a difference.

@andy2 -


       Very little to nothing can be done*; to improve the sound of truly inferior audio components.

        *nor: To dispel the lingering miasma of a Denyin'tologist and the severely limited 19th Century Electrical Theory, to which they cling.

                                                 Happy listening!