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oldmanStrat 31st May 2009 10:49 PM

How can a resistor "sound" good?
 
I was looking at the Musical Machine and in the parts description the author talks about how it's important to have high quality resistors because it affects the sound.

How? It's a resistor... some kind of heating effect that changes the resistance? Possibly inductance if it is a wire wound?

Just curious, it's the first time I've heard that resistors can effect the sound...

gingertube 1st June 2009 12:18 AM

We are mostly talking about noise performance. Thermal noise proportional to the resistance value is introduced by a resistor. Carbon Composition are much worse compared to metal film and wire wound are better than metal film.
The other thing we see is that Carbon Film resistors have a voltage dependency. That is, their resistance changes with voltage across the resistor. This introduces some second harmonic distortion. Rikken Ohms do this. If the amp has too much 3rd and other odd order distortion then addition of a carbon film resistor to add some 2nd harmonic just may make the amp sound better, by masking / balancing some of the odd harmonic distortion. (Of-course it would have been better to find what was causing the excess odd harmonic distortion and fix that instead).
Cheers,
Ian

HollowState 1st June 2009 01:17 AM

Re: How can a resistor "sound" good?
 
Quote:

Originally posted by oldmanStrat

How? It's a resistor...
Just curious, it's the first time I've heard that resistors can effect the sound...

Quote:

Originally posted by gingertube
We are mostly talking about noise performance. Thermal noise proportional to the resistance value is introduced by a resistor. Carbon Composition are much worse compared to metal film and wire wound are better than metal film.
This is mostly true. However, it is curious to remember that all the old RCA Living Stereo and Mercury Living Presence recordings of the 50's and 60's, that golden eared audiophiles swoon over for their glorious sound quality, were produced on equipment that was filled with carbon composition resistors. That's all they used, with the possible exception of the very lowest level input stage where you might find a wire-wound plate resistor.

It's also been my experience that metal film resistors will provide an increase in high frequence response over carbon comps when used directly in the signal path.

ccschua 1st June 2009 01:35 AM

What Ian says is quite true as I have just tried with tweaking Riken resistors in tube amp. However too many of these resistors will sound 'color'. I have used Rien to grid stoppers and feedback resistors and quite happy with it.

Wavebourn 1st June 2009 01:57 AM

Quote:

Originally posted by ccschua
What Ian says is quite true as I have just tried with tweaking Riken resistors in tube amp. However too many of these resistors will sound 'color'. I have used Rien to grid stoppers and feedback resistors and quite happy with it.
Feedback resistors? :eek: Happy with introducing distortions? :bigeyes: Did you try diodes in feedback? :cool:

ccschua 1st June 2009 02:04 AM

Feedback resistors - Second harmonic feedback ? Yes , no?:confused:

Wavebourn 1st June 2009 03:27 AM

Quote:

Originally posted by ccschua
Feedback resistors - Second harmonic feedback ? Yes , no?:confused:
If no DC bias distortions are symmetrical. That means, no even harmonics in them.

gallon 1st June 2009 03:34 AM

Quote:

Originally posted by gingertube
...
The other thing we see is that Carbon Film resistors have a voltage dependency. That is, their resistance changes with voltage across the resistor. This introduces some second harmonic distortion. Rikken Ohms do this. If the amp has too much 3rd and other odd order distortion then addition of a carbon film resistor to add some 2nd harmonic just may make the amp sound better, by masking / balancing some of the odd harmonic distortion. (Of-course it would have been better to find what was causing the excess odd harmonic distortion and fix that instead).
Cheers,
Ian


Long ago I saw an Allen Bradley data sheet showing a severe vcr for their carbon composition resistors. Wish I could find that again.

Gary

Conrad Hoffman 1st June 2009 03:40 AM

Resistors have their well known characteristics like temperature coefficient, voltage coefficient, stray capacitance and inductance. You can compare them based on those parameters and make definite statements that are reproducible by others. IMHO, the accounts of resistors being responsible for variations in sound are so contradictory and sometimes contrary to what resistors are known to affect, that I can only take them as audio myth and lore. There may be a few applications like critical locations in tube amps where some valid generalizations could be made. Or not. In any case, I try to build with stable quality parts having as low a TC, VC and other secondary effects, as is practical, but you won't find $10 resistors in anything I build other than lab standards type equipment like voltage references or precision dividers.

jameshillj 1st June 2009 03:41 AM

It's strange thing but it's a few years since the Ellen bradley resistors were available, particularly the 1/2 watt ones - today, it's only the higher 2 watt ones that appear on eBay - the 1/2 watters seem to have completely dissapeared and are only available at boutique sites at a couple $s each.
It seems that Rikken, as you use, is the modern substitute, and not cheap either!


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