Noise In Resistors - How Important For Audio Attenuation?

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tortugaranger

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In a recent Audio Precision (www.ap.com/) newsletter a Bruce Hofer highlights the negative effects of resistor temperature and resistance on audio noise. He suggests audio signals be subjected to the lowest possible resistance to minimize noise. Of course in designing an audio volume control (LDR or otherwise) the audio signal can be subject to fairly high resistance especially at lower volumes.

Hofer's caution notwithstanding, how significant do you think this really is?

I captured the article below but it turned out too small to read. You can access it here: http://www.icontact-archive.com/kMnNjucz6ZH1xiBCGDasRMwOmNgm6bfJ?w=4#


jtwrace

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Re: Noise In Resistors - How Important For Audio Attenuation?
« Reply #1 on: 1 Sep 2013, 12:29 pm »
Well, this leads to the next question then....when will you be posting measurements of your LDR? 

Speedskater

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Re: Noise In Resistors - How Important For Audio Attenuation?
« Reply #2 on: 1 Sep 2013, 03:01 pm »
Back to the resistor question, if it's the first stage of a moving-coil pre-amp or the first stage of some microphone pre-amplifiers, then low resistor noise is important!  There is not much wiggle-room in those first stages but 40dB later at line level signals, any quality resistor is fine.

We are at a point where test instruments can measure extremely small values and Audio Precision likes to point out all the measurements that their expensive meters can do.

tortugaranger

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Re: Noise In Resistors - How Important For Audio Attenuation?
« Reply #3 on: 1 Sep 2013, 05:58 pm »
Well, this leads to the next question then....when will you be posting measurements of your LDR?

Moved this to its own LDRx measurement topic.

richidoo

Re: Noise In Resistors - How Important For Audio Attenuation?
« Reply #4 on: 1 Sep 2013, 10:35 pm »
George Stantschleff attributed the sonic benefits of LDR to the elimination of the micro-arcing in temporary contacts of normal volume controls. The arcing is a much louder source of non-linear noise than the thermal noise of resistors.

What is the lowest noise type of resistor? Metal film? Graphite?