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...
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...
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
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
oldmanStrat said:
gingertube said:
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.
Did you try diodes in feedback?
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.
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!
It seems that Rikken, as you use, is the modern substitute, and not cheap either!
Wavebourns point above is important - if there is no DC bias across the Carbon Composition then distortions are symmetrical, that is, no additional 2nd harmonic. When used as anode loads and similar however you do get a DC bias and so distortion is asymmetrical and you do get additional 2nd harmonic distortion.
I started playing with Rikken Ohms (back before I saw the light) when I was playing in the sand pit designing and building SS amps. A Rikken Ohm or 2 in the right place could mask all sorts of nasties. I quickly found that taking out the Rikken Ohms and fixing the underlying problem(s) was a far superior way to go. That eventually gave me a "sniff sniff" superior attitude to Rikkens and similar. When ever I saw one in a circuit (a lot of CD player "upgrades" use them) I started to wonder what limitations / nastiness they were trying to conceal.
I have never used Rikkens in a tube amp.
Cheers,
Ian
I started playing with Rikken Ohms (back before I saw the light) when I was playing in the sand pit designing and building SS amps. A Rikken Ohm or 2 in the right place could mask all sorts of nasties. I quickly found that taking out the Rikken Ohms and fixing the underlying problem(s) was a far superior way to go. That eventually gave me a "sniff sniff" superior attitude to Rikkens and similar. When ever I saw one in a circuit (a lot of CD player "upgrades" use them) I started to wonder what limitations / nastiness they were trying to conceal.
I have never used Rikkens in a tube amp.
Cheers,
Ian
If putting a resistor directly in the feedback loop, consider the input current of the feedback device. Often this current will be nonlinear with voltage, creating a nonlinear voltage drop across the resistor, which injects distortion. This should have little if any affect on more precise amps with lots of OLG, and I don't know about tubes since I've never messed with them.
But just something to consider before we assume it's the resistor causing the distortion rather than something else.
- keantoken
But just something to consider before we assume it's the resistor causing the distortion rather than something else.
- keantoken
Re: Re: How can a resistor "sound" good?
Perceived or measured?
Carbon comps' biggest offenses are noise, tolerance, and voltage-dependent resistance, but they are not significantly reactive compared to spiral film resistors, so high frequencies should not be a problem. You might find, however, a perception of less high frequency "energy", because they are less likely than film resistors to induce parasitic oscillations that might intermodulate their way back into the audio signal. A good compromise, of course, is the metal glaze resistor - which can do decent power, has low inductance, doesn't blow up with pulses, and has lower noise and VDR nonlinearity than a carbon comp.
HollowState said:
Perceived or measured?
Carbon comps' biggest offenses are noise, tolerance, and voltage-dependent resistance, but they are not significantly reactive compared to spiral film resistors, so high frequencies should not be a problem. You might find, however, a perception of less high frequency "energy", because they are less likely than film resistors to induce parasitic oscillations that might intermodulate their way back into the audio signal. A good compromise, of course, is the metal glaze resistor - which can do decent power, has low inductance, doesn't blow up with pulses, and has lower noise and VDR nonlinearity than a carbon comp.
Re: Re: How can a resistor "sound" good?
Morgan Jones valve amps 3rd edit. Has no time for carbon resistors. Quote p.204; <Only as grid stoppers>. The rest of his comments on p.202 are comical.
Well ? I replaced this carbon comp resistor (in pic) in the signal path from a 6L6 amp made in 1957 because it was wildly out of tolerance (+30%).By fitting a newer replacement I was expecting a sound difference but I was dissapointed. One must expect a large drift from carbons over a period of time.
Strangely, after 40 yrs I am returning to wirewounds as anode loads. They are far more stable and in comparison noise free.
richy
HollowState said:
Morgan Jones valve amps 3rd edit. Has no time for carbon resistors. Quote p.204; <Only as grid stoppers>. The rest of his comments on p.202 are comical.
Well ? I replaced this carbon comp resistor (in pic) in the signal path from a 6L6 amp made in 1957 because it was wildly out of tolerance (+30%).By fitting a newer replacement I was expecting a sound difference but I was dissapointed. One must expect a large drift from carbons over a period of time.
Strangely, after 40 yrs I am returning to wirewounds as anode loads. They are far more stable and in comparison noise free.
richy
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I remember carbon resistors used in telephone receivers... They sounded very specifically, their membranes were metallic, so the sound was metallic. Also, they changed properties with age because carbon particles were becoming thinner, and used to bake to each other. Also, they could not be totally hermetic, so a moisture from user's breathing affected them...
The same, about carbon comp resistors in amps: change properties with age, moisture, heat, current, voltage, non-linear, noisy. But can withstand short overload (bigger physical volume of resistive substance is needed for the same power rating than for film resistors), like slo-blo fuses.
The same, about carbon comp resistors in amps: change properties with age, moisture, heat, current, voltage, non-linear, noisy. But can withstand short overload (bigger physical volume of resistive substance is needed for the same power rating than for film resistors), like slo-blo fuses.
Hi,
That come to no surpise to me, anode loads and WW resistors work well together.
Anyone remember Holco resistors?
Built a preamp or amp using only that brand of resistors and you'll definitely "hear' what that resistor really sounds like.
Same for caps, wire, valves, etc., etc.
Trick is to know these little colorations and use them like a chef in his kitchen.
Too much of a good thing.....
Cheers,
That come to no surpise to me, anode loads and WW resistors work well together.
Anyone remember Holco resistors?
Built a preamp or amp using only that brand of resistors and you'll definitely "hear' what that resistor really sounds like.
Same for caps, wire, valves, etc., etc.
Trick is to know these little colorations and use them like a chef in his kitchen.
Too much of a good thing.....
Cheers,
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