Resistor sound, minus snake oil.

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FriedMule

Member
2018-04-17 3:08 am
Denmark
  • #1
    As the title says am I wondering / asking about the resistors real sound, not if freezing them in a cryogenic frozen Nike shoo while Santa Claus is spreading Easter-dust, do make any diference.:)


    Resistors are made with different materials and techniques, so I can imagine that they have different heat, emf, capacitance and induction reactions. But on top of that, do resistors not add noise, distortions, harmonics and thereby change the sound?
    I know that we may be talking about so a little influence that no person can here it, but if the signal is very small, like in an amplifier and there are a lot of them, do thy then make any change in sound?
     
    indianajo

    indianajo

    Member
    2010-01-13 6:02 pm
    Jeffersonville, Indiana USA
  • #4
    I looked at the first page of What causes resistor distortion?
    Lets cut to the chase. I have over a thousand carbon comp resistors from 1961 to 1968 in dynaco amps and hammond & wulritzer organs. When I changed the 270 k & 470 k in my ST70 amp to metal film (vishay, multicomp/farnell), the idle hiss was substantially reduced. Maybe 3 db. This was predicted by this site. Under 100 k the effect is not so noticable. This is called "thermal noise".
    In the distortion thread post about # 6 mentioned carbon comp value wandering due to moisture. Most posters on diyaudio.com are from Europe, and haven't seen carbon comp resistor 1961 to 1985? from Allen Bradley and Sprague. About 1961, some kind of paint was put on RCR07g etc. resistors that ran on the "mil spec" lines, even the ones with commercial part numbers that looked the same. These resistors do not vary in value due to moisture, unless overheating destroys the paint. Probably the US Navy was involved in the research. I've seen no announcements about the changeover. In particular my dynaco ST70 & PAS2 lived in 100% humidity Houston, TX the first 30 years of their lives and the carbon comp resistor values did not change: all were within 10% of nominal. Two lean post college years I didn't air condition my house, until mold grew on the walls.
    There still might be a problem with value decrease of the 1-10 megohm ones; hammond repairers don't mention chassis build date usually. Hammond organs built in the Netherlands have been reported to have unreliable resistor values near the sea. Particularly an X66 owner that lived on one of the UK channel islands. He had to change every resistor out due to value variance; hundreds on this premium 200 kilogram model. Those resistors look just like the US made ones. The paint looks the same. Obviously, it is not. My 1966 to 1968 Hammond organs do not have carbon comp resistor value change, except the ones where underrated wattage burned the paint. David of NC, a guitar amp & organ repairman, says HH Scott equipment post 1961 also had the everlast carbon comp resistors.
    As Hammond organs have a motor+tone generator whirr noise that covers up amplifier hiss, I'm not changing the carbon comp resistors: except the 10 k 1/2 watt in the power amp of two H100's, that were both burned and reading 11.5 to 12.5 K. Those were changed out during electrolytic cap replacement 2010-2012.
     
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    FriedMule

    Member
    2018-04-17 3:08 am
    Denmark
  • #7
    indianajo said:
    I looked at the first page of What causes resistor distortion?
    Lets cut to the chase. I have over a thousand carbon comp resistors from 1961 to 1968 in dynaco amps and hammond & wulritzer organs. When I changed the 270 k & 470 k in my ST70 amp to metal film (vishay, multicomp/farnell), the idle hiss was substantially reduced. Maybe 3 db. This was predicted by this site. Under 100 k the effect is not so noticable. This is called "thermal noise".
    In the distortion thread post about # 6 mentioned carbon comp value wandering due to moisture. Most posters on diyaudio.com are from Europe, and haven't seen carbon comp resistor 1961 to 1985? from Allen Bradley and Sprague. About 1961, some kind of paint was put on RCR07g etc. resistors that ran on the "mil spec" lines, even the ones with commercial part numbers that looked the same. These resistors do not vary in value due to moisture, unless overheating destroys the paint. Probably the US Navy was involved in the research. I've seen no announcements about the changeover. In particular my dynaco ST70 & PAS2 lived in 100% humidity Houston, TX the first 30 years of their lives and the carbon comp resistor values did not change: all were within 10% of nominal. Two lean post college years I didn't air condition my house, until mold grew on the walls.
    There still might be a problem with value decrease of the 1-10 megohm ones; hammond repairers don't mention chassis build date usually. Hammond organs built in the Netherlands have been reported to have unreliable resistor values near the sea. Particularly an X66 owner that lived on one of the UK channel islands. He had to change every resistor out due to value variance; hundreds on this premium 200 kilogram model. Those resistors look just like the US made ones. The paint looks the same. Obviously, it is not. My 1966 to 1968 Hammond organs do not have carbon comp resistor value change, except the ones where underrated wattage burned the paint. David of NC, a guitar amp & organ repairman, says HH Scott equipment post 1961 also had the everlast carbon comp resistors.
    As Hammond organs have a motor+tone generator whirr noise that covers up amplifier hiss, I'm not changing the carbon comp resistors: except the 10 k 1/2 watt in the power amp of two H100's, that were both burned and reading 11.5 to 12.5 K. Those were changed out during electrolytic cap replacement 2010-2012.
    Click to expand...
    What a great and interesting answer!
    200 Kg, wow, I cant imagine how one would feel right before grabbing the screwdriver:)

    I think that you would have "destroyed"the sound if you had changed every resistor, I think that the resistors is part of the old sound and is part of it's "soul".

    But when building new, it may be a good thing to think before just buying 50 of the cheapest from DigiKey or Mouser.
    I have not yet read all the comments about resistor noise but I believe to have an idea of the Metal Foil (not film) being the one with lowest THD+N, on the other hand, how do that effect my target sound.
    I did ask Mooly about if I should go hunting after audio resistors, but he think as I do, it may not be all that it is turned out to be. That "normal" transistors is good enough, but then again do I think, if I am about to buy a handful resistors, why not get quality and the right type?


    Am just not sure what is the right kind?:)
     
    JMFahey

    JMFahey

    Member
    2009-03-18 7:32 pm
    Buenos Aires - Argentina
  • #10
    FriedMule said:
    It depends on how you look at it, if you measure different resistors, do you get different response curves, noise levels and types, you do also get different thermal changes. So all that combined, have to do something, maybe not much but still:)
    Click to expand...
    we may be talking about so a little influence that no person can here it
    Click to expand...
    Anything well below threshold of audibility is, well, inaudible.
     
    M

    MarcelvdG

    Member
    2003-03-14 3:00 pm
    Haarlem, the Netherlands
  • #11
    Technically, there are differences in 1/f noise, accuracy, parasitic capacitance and inductance, power handling and distortion, among other things, and it all depends on the application what is important and what not.

    For example, DACs that use resistors to set the bit weights usually need very accurate resistors with low parasitic capacitance. Parasitic inductance can be an issue for very low value resistors inside a feedback loop, such as emitter resistors in amplifier output stages or feedback resistors of current driving amplifiers. 1/f noise is important in low-noise preamplifiers, particularly when there is a DC bias current flowing through the resistor. The distortion is in most cases totally negligible, but not for the instrumentation application Jan Didden is looking into.

    By the way, unlike 1/f noise, the thermal noise only depends on the temperature and the resistance.
     
    indianajo

    indianajo

    Member
    2010-01-13 6:02 pm
    Jeffersonville, Indiana USA
  • #15
    FriedMule said:
    I think that you would have "destroyed"the sound if you had changed every resistor, I think that the resistors is part of the old sound and is part of it's "soul".
    Click to expand...
    The "sound" of a hammond tonewheel organ comes from the cut of the tonewheels, the capacitors in series with the pickups, and the mixer transformers, that add different notes together at a nearly constant volume due to the saturation of the core. There are three classes of B3 sound, the deteriorated paper capacitor sound of late 1970's recordings, and the bright original sound before the paper dielectric deteriorated. Modern film capacitors don't replicate either one. Paper to film capacitor change happened spring 1966. My 1966 A100 has one paper Tone Generator capacitor, the rest polyester.
    The "sound" of the X66 came from RLC circuits that created the "formants" of the notes. Accent being on the L's and the C's.
    I'm with CBDB, except carbon comp hiss versus metal film. I find resistor differences of other types too subtle to hear behind the distortions of speakers and crossovers.
     
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    FriedMule

    Member
    2018-04-17 3:08 am
    Denmark
  • #16
    Mooly has written about the Wattage on the "special" resistors, but what about the "normal" types?
    Hmm I may break my own rule here but if we kick logic out to the curve. The Vishay Dale RL/RN/CMF looks like being highly regarded as high quality and good sound.
    Have any of you heard that, is it true, forgetting about measuring:)
     
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