Some metal film resistors are nonmagnetic, but test to be sure.
These are an example, very good and relatively inexpensive.
https://www.vishay.com/docs/31091/cmfnonma.pdf
Just for those who like to buy non-magnetic reistors ...
I bought a bunch of PTF56 and CPF1..3 from Mouser and all were non-magnetic.
I checked with a neodymium magnet and non of the resistors moved even a micrometer.
I have a lot of PTF56 and CPF at home and they are all non-magnetic
as well. Usually some RN55 types are officially specified as non-magnetic by Vishay.
I wonder that no datasheet mentions that the PTF56 and CPF types are
non-magnetic also. The PTF56 has some additional advantages as it is said to be
very low noise (?) and it is available with very tight temco of 5..10ppm as well.
5 kOhms is available from a polish Ebayer at the moment for a good price.(Search)
All resistors i mentioned are Vishay/Dale 0.1%. The PTF56 i own are at least 10ppm.
I like the dark blue color ;-).
I bought a bunch of PTF56 and CPF1..3 from Mouser and all were non-magnetic.
I checked with a neodymium magnet and non of the resistors moved even a micrometer.
I have a lot of PTF56 and CPF at home and they are all non-magnetic
as well. Usually some RN55 types are officially specified as non-magnetic by Vishay.
I wonder that no datasheet mentions that the PTF56 and CPF types are
non-magnetic also. The PTF56 has some additional advantages as it is said to be
very low noise (?) and it is available with very tight temco of 5..10ppm as well.
5 kOhms is available from a polish Ebayer at the moment for a good price.(Search)
All resistors i mentioned are Vishay/Dale 0.1%. The PTF56 i own are at least 10ppm.
I like the dark blue color ;-).
"none"
I would'nt say it like that. Consider the good feeling, having build the best amplifier and
gaining esoteric expertise. I mean music is only happening just within our heads.
So you have to consider the stored context there, which is crucial for what you
finally will experience. What is comming from our speakers or headphones is just
acustical patterns! Meaningless acustical patterns! So, what happens in our heads is,
what finally counts. The presence and knowledge of non-magnetic
resistors in our equipment may thus enhance happiness a lot. Have fun ;-)
I would'nt say it like that. Consider the good feeling, having build the best amplifier and
gaining esoteric expertise. I mean music is only happening just within our heads.
So you have to consider the stored context there, which is crucial for what you
finally will experience. What is comming from our speakers or headphones is just
acustical patterns! Meaningless acustical patterns! So, what happens in our heads is,
what finally counts. The presence and knowledge of non-magnetic
resistors in our equipment may thus enhance happiness a lot. Have fun ;-)
It is, of course, also important to use non-magnetic microphone transformers, non-magnetic turntable pickup cartridges, non-magnetic balanced line transformers, non-magnetic OPTs (in valve amps) and, ideally, non-magnetic loudspeakers. Oh, I forgot, non-magnetic valve anodes too. Keep all ferromagnetic materials well away from whatever you imagine the signal path to be.
I wish I could have those transformers, mine pick RFI noise real bad without proper shielding. BTW, non magnetic tungsten electrode electrostatic speakers do sound real nice except for the price.
Same here, I also forgot, my RCA carbon anode do pick up far less RFI noise from the house led drivers and SMPS supplies compared to the regular nickel anodes. Sadly my only pair is getting rather weak and the current NOS price has already moved to the extortion range, similar to the way copper lead tantalum resistors go.
I think you forgot about Abraham Lincoln in your list.
I only smoke non-magnetic crack.
Last edited:
Electrical shielding will be far more effective for blocking that kind of RF noise.
Of course, but I will lose the aesthetic of my 801A preamp by shielding while my graphite anode tubes are good enough as is. My point is that material used to make the parts do make a some difference. At AKSA's Lender Preamp with 40Vpp Output thread, xrk971 successfully track a difficult to find issue found to be a metal (oxide?) film smd resistor used as feedback which he solved by using carbon smd resistor.