Inductors as an Audio Enhancer

[Newman]

I have an audio friend who is a huge fan of the use of inductors in audio circuits, saying their energy storage is key to better sound quality…he seems to hint at extra dynamics and less noise.

Does anyone here, who reads subjective audio forums widely, understand what the in-principle argument is, how this is meant to be an advantage?

He prefers choke power supplies for single ended valve amps. Now that one I can understand may be a benefit, effectively being a choke load on the anode and delaying the point at which the output would clip as signal rises.

But he takes it further.

He uses transformer volume controls, saying they sound better than passive resistor volume controls because of the way inductors store energy.

He is building passive loudspeaker crossovers that are inductor-intensive and capacitor-light.

He has in mind an RIAA circuit that “is entirely inductor based”… not sure if that means no capacitors, or also minimal resistors. He showed me a test inductor that he is winding with what looks like a ferrite drum sleeve.

At every opportunity where he could replace a resistor or a capacitor with an inductor (I don’t mean to literally substitute: I mean with a different circuit that still serves the intended function), he is looking for ways to do it.

Is this a bogus argument from an electrical engineering perspective? Why? What is the correct argument?

Thanks for any thoughts.

 

[antcollinet]

Sounds like nonsense to me. Why wouldn't capacitor energy storage be just as beneficial?

Why does energy storage result in better sound quality in any case?

And why is it possible to make high quality components with any artifacts orders of magnitude below the level of audibility without any inductors at all?

 

[Philbo King]

I wonder what he'll do about the satanic interwinding capacitance?

Seems like a harmless form of fanaticism though. Perhaps it is a growth phase for him.

 

[Timcognito]

Is there a difference in rate or decay of delivery of energy between an inductor or a capacitor? My last EE class was 1976.

 

[Sokel]

Jealous much???

(Halcro)

If he also achieves such performance I bow to him!

 

[antcollinet]

Is there a difference in rate or decay of delivery of energy between an inductor or a capacitor? My last EE class was 1976.

No, they are directly analogous.

Capacitors store energy in an electrostatic field. Inductors in an electromanetic field.

Replace volts with amps, amps with volts, electrostatic with electromagnetic. Real capacitors have resistance and stray inductance. Real inductors have resistance and stray capacitance - mathematically they are the same.

It may even be easier to get closer to an ideal capacitor, than it is to an ideal inductor.

 

[MaxwellsEq]

In theory every circuit using exclusively R and C components has an equivalent using R an L components. Sometimes, practically, inductors make more sense than capacitors and sometimes not. I can imagine that his approach is possible, but he may make unnecessary hardships for himself, with tricky to quantify justification.

 

[mhardy6647]

intact audio

hifi heroin

new school ideas meet old school junk.

hifiheroin.blogspot.com

 

[DVDdoug]

Yeah... Nonsense...

Inductors are rarely used in "regular" audio circuits because the inductive reactance (impedance) is too low at audio frequencies (for practical inductor values). It can be done, but there are serious downsides. They are used everyday in speaker crossovers where the impedance is much lower.

Inductors are somewhat the opposite of capacitors...

This is over-simplified but...
Capacitors in series are high pass filters, and they block DC (zero Hz). Frequently they are used to block DC (i.e. DC from the power supply) in the audio path while letting the AC audio signal through.
Capacitors in parallel are low-pass filters. In a power supply they convert rectified AC to pure DC and they can filter-out noise.

Inductors in series are a low-pass filter.
Inductors in parallel are a high-pass filter.

Inductors, or the inductance of a transformer, is often used as part of the oscillator & filter in a switch-mode power supply. Or they can be an RF filter in the power supply (in series with the DC voltage).

 

[mhardy6647]

Inductors are rarely used in "regular" audio circuits because the inductive reactance (impedance) is too low at audio frequencies (for practical inductor values). It can be done, but there are serious downsides. They are used everyday in speaker crossovers where the impedance is much lower.

Plenty of impracticality in "high end" audio, though.

From the guy who proved (or at least demonstrated) that he could make a ss amplifier sound like a tube amplifier.
So... there you go, then!


PS Note that the monstrous monoblocks above are not OTL amplfiers! We'll give Atma-Sphere and @ralph a pass because it takes a fair number of output tubes in series-parallel not to use some inductors (ahem, transformers) 'twixt power tubes and loudspeakers.

 

[Killingbeans]

He is building passive loudspeaker crossovers that are inductor-intensive and capacitor-light.

Energy stored as a magnetic field sounds better than energy stored as an electric field?

Yeah, that's nonsense. Energy is energy.

Maybe he means that magnetic reluctance is somehow better than capacitive reactance? Doesn't make sense to me either.

Either way, I'm in over my head. I'll let the EE's take it from here.

 

[thegeton]

Energy stored as a magnetic field sounds better than energy stored as an electric field?

This is my question as well.

 

[Cbdb2]

Just enough knowledge to do damage. Inductors are usually more lossy than caps due to the resistance of the wire. Iron cores add to the losses (Eddy currents) can saturate and have hysteresis. Charge up a cap, disconnect, how longs it take to discharge? Run a current thru an inductor, disconnect, how long will the current run? Which stores the energy better (at room temp)?
You'll never see an inductor in an integrated circuit, you will see small caps.

 

[Cbdb2]

Energy stored as a magnetic field sounds better than energy stored as an electric field?

Yeah, that's nonsense. Energy is energy.

Maybe he means that magnetic reluctance is somehow better than capacitive reactance? Doesn't make sense to me either.

Either way, I'm in over my head. I'll let the EE's take it from here.

Energy stored dosnt sound like anything. Its the release/transfer of energy that makes sound. Illd love to see his inductor based linear power supply.

 

[mhardy6647]

Just enough knowledge to do damage. Inductors are usually more lossy than caps due to the resistance of the wire. Iron cores add to the losses (Eddy currents) can saturate and have hysteresis. Charge up a cap, disconnect, how longs it take to discharge? Run a current thru an inductor, disconnect, how long will the current run? Which stores the energy better (at room temp)?
You'll never see an inductor in an integrated circuit, you will see small caps.

... but SMPS and many other circuits are still chock full of 'em
In the case of SMPS, mostly to undo the damage that the SMPS does in terms of noise.

 

[Newman]

Energy stored dosnt sound like anything. Its the release/transfer of energy that makes sound. Illd love to see his inductor based linear power supply.

Probably like this:

 

[Newman]

Yeah... Nonsense...

Inductors are rarely used in "regular" audio circuits because the inductive reactance (impedance) is too low at audio frequencies (for practical inductor values). It can be done, but there are serious downsides. They are used everyday in speaker crossovers where the impedance is much lower.

Inductors are somewhat the opposite of capacitors...

This is over-simplified but...
Capacitors in series are high pass filters, and they block DC (zero Hz). Frequently they are used to block DC (i.e. DC from the power supply) in the audio path while letting the AC audio signal through.
Capacitors in parallel are low-pass filters. In a power supply they convert rectified AC to pure DC and they can filter-out noise.

Inductors in series are a low-pass filter.
Inductors in parallel are a high-pass filter.

And Inductors in a volume control are a ....?

Inductors, or the inductance of a transformer, is often used as part of the oscillator & filter in a switch-mode power supply. Or they can be an RF filter in the power supply (in series with the DC voltage).

 

[Cbdb2]

Probably like this:
View attachment 331327

No thats a transformer and a cap, the cap is storing the energy, does that work/

 

[Prana Ferox]

Along with what the above have said, if you're replacing a resistive component with a reactive one (i.e. a resistive pot with a transformer for volume) it's going to have some effect on frequency response.

In general out of all the components in a crossover and generally in any audio electric circuit, inductors are the biggest hassle to get sized right - they're frequently just plain physically large (even at surface mount scales the inductors are obvious) and larger inductors in variable frequency circuits (aka audio) have bad habits of interfering with each other. That's why you have goofy rules about crossover inductor placement, no one really cares if you point a capacitor or resistor at each other. In the worst worst case they can even vibrate and make audible noise on their own.

 

[AlfaNovember]

And Inductors in a volume control are a ....?

Inductive volume controls are usually tapped autoformers. 70V distribution systems sometimes use them as wall-mounted junction box volume controls, rather than resistive elements. I suppose on a distribution system it's less efficient to turn the excess energy into heat via a resistive element, whereas the electromagnetic field of an autoformer transfers only the fraction of the signal energy needed, plus minor resistive losses inherent to the coil.