Is there a reason based in physics for not using magnetic resistors or just the typical audiophoolery?
Hysteresis. Resistors that are magnetic will have higher distortion than metal film units that are not. But they will probably distort less than carbon composition resistors.
You could put a very stylish mesh screen around it.
Materials can certainly make a difference, but not necessarily for the reasons you're inferring. Metal film resistors usually have a spiral track, which can cause instability in a feedback loop due to the resulting inductance.
The only thing I can find ( from Vishay ) is that they don't pick up stray magnetic fields which makes sense. Nothing about hysteresis. Feels like a straw man. Weak magnetic material, very low currents, negligible effect. Show me some numbers.
Very unlikely. The inductance is small, and only likely to have any effect in a VHF/UHF circuit - not audio.AquaTarkus said:
Did you read my mind? That is exactly what I use for shielding the metal anode ones, though I prefer the looks without.
Agreed, there are too any things beyond what I know, I only offer what little experience I had, and I could be wrong. It is just that I really appreciate those sharing their work advancing the horizon.
For clarity, I think I need to elaborate bit. The main issue appeared as high H3 generation, not instability (could be related but not measured nor mentioned). Xrk971 tracked the issue to the use of some (thick film?) metal (oxide?) smd resistors on the feedback resistor position, an el cheapo chinese regular metal film through hole resistor (presumably with typical spiral track?) tested at that position did not exhibit such issue, no mention about magnetic property on the regular through hole resistor, no such issue on the use of similar thick film resistor on other position. And he never claim exhaustive testing.
So to prevent future confusion, I repeat, xrk971 finding is exclusively on the use of thick film smd resistor at feedback resistor position, nothing on regular through hole metal film resistor with the presumably spiral geometry, nor any resistor used at other position.
Resistor distortion, when it occurs, is usually because of the difficulty of getting a good low resistance joint from the wires to the resistive element. Having magnetic wires is not a problem. At audio frequencies the inductance (which couples to the ferromagnetic wire) is small, so no problem. At RF frequencies the current is in the plating due to skin effect, so again no problem.
Maybe magnetic/non-magnetic has nothing to do with any anything except the non-magnetic leads are copper instead of steel.
Craig
Craig
Some of my most favourite resistors are magentic. Or maybe not.
Others resistors that I really like have considerable inductance. Except for the ones that don't.
And some of the VERY best signal path resistors I now use are incredibly CHEAP, easily sourced in a wide range of values and are NOT at all NOS.
Others resistors that I really like have considerable inductance. Except for the ones that don't.
And some of the VERY best signal path resistors I now use are incredibly CHEAP, easily sourced in a wide range of values and are NOT at all NOS.
Wasn't that another article concluding wirewound are top performers?
I recently read a few resistor noise investigations coming to the same conclusion. A current fav for tube circuits right now is the Ohmite WN/WH series at $1/pop, <1nH @ 1MHz.
yes,
Eddy Current magnetic fields in magnet resistors the Eddy current effect will be worse than nonmagnetic resistors
making audio sound not as good.
Eddy Current magnetic fields in magnet resistors the Eddy current effect will be worse than nonmagnetic resistors
making audio sound not as good.
