Hello.
Is there any collective knowledge regarding the sound of volume pots, and specifically, regarding the materials?
Observant people can generalize about the characteristic sounds of pure vs plated wire, or polypropylene vs electrolytic, or tube vs transistor. There must be some common knowledge about pots -- or maybe we can construct some kind of framework right here.
My current setup is cermet pots with curve-shaping resistors added. There are some people who obviously know that cermet is the best. There are some people who obviously know that cermet is the worst. And conductive plastic and deposited carbon and hot-molded carbon and whatever else I don't know about.
What is the general sonic tendency of each of these materials?
Of course other things matter and the edges of the groups are going to blend, but that's not a reason to withhold our experience.
And -- for the inevitable person who is going to barge in and say that there is no such thing as groupable characteristics -- let me just say that your position is probably uninformed.
Thank you kindly.
Is there any collective knowledge regarding the sound of volume pots, and specifically, regarding the materials?
Observant people can generalize about the characteristic sounds of pure vs plated wire, or polypropylene vs electrolytic, or tube vs transistor. There must be some common knowledge about pots -- or maybe we can construct some kind of framework right here.
My current setup is cermet pots with curve-shaping resistors added. There are some people who obviously know that cermet is the best. There are some people who obviously know that cermet is the worst. And conductive plastic and deposited carbon and hot-molded carbon and whatever else I don't know about.
What is the general sonic tendency of each of these materials?
Of course other things matter and the edges of the groups are going to blend, but that's not a reason to withhold our experience.
And -- for the inevitable person who is going to barge in and say that there is no such thing as groupable characteristics -- let me just say that your position is probably uninformed.
Thank you kindly.
Are you trying to start a new religion?
We already have paper-in-oil true believers, battery noise worriers, oxygen content priests ...... and keep counting.
All of which waste time and resources which might better spent on solving REAL Audio problems.
We already have paper-in-oil true believers, battery noise worriers, oxygen content priests ...... and keep counting.
All of which waste time and resources which might better spent on solving REAL Audio problems.
And there was I thinking they were just imaginative people.Bamalama said:
Components don't have a sound. Badly-chosen components in a circuit may have a sound - in most cases the solution is to use a better circuit, although sometimes a more appropriate component may be the answer.
I've seen old volume pots that generated a lot of modulation noise that was visible on a THD analyser, or had a bad wiper contact that was sensitive to vibration.
I eventually traced the distorted sound of my old Peavey bass guitar to this issue, the vibrations from the strings were causing the volume pot wiper to make and break contact. I replaced it with a fancy Bourns conductive plastic part and the improvement was remarkable, but that was because the old one was broken.
I would like to think that a good quality conductive plastic pot in good condition (Alps Blue Velvet etc) should not degrade the sound quality of a hifi system noticeably. Certainly the measured noise and distortion performance is better than you get from a digital attenuator like the PGA2310.
I don't know about groupable characteristics. I certainly don't subscribe to the simplistic notion that the electrical properties of materials are related to their mechanical ones. (metal film resistors sound metallic, carbon composition dark etc)
I eventually traced the distorted sound of my old Peavey bass guitar to this issue, the vibrations from the strings were causing the volume pot wiper to make and break contact. I replaced it with a fancy Bourns conductive plastic part and the improvement was remarkable, but that was because the old one was broken.
I would like to think that a good quality conductive plastic pot in good condition (Alps Blue Velvet etc) should not degrade the sound quality of a hifi system noticeably. Certainly the measured noise and distortion performance is better than you get from a digital attenuator like the PGA2310.
I don't know about groupable characteristics. I certainly don't subscribe to the simplistic notion that the electrical properties of materials are related to their mechanical ones. (metal film resistors sound metallic, carbon composition dark etc)
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You piqued my curiosity, so I just tried measuring the THD+N in an Alps 10k linear pot, set to the -6dB potision, with 15Vrms input, using an AP1. I could detect nothing but noise across the full audio range (noise floor hovering around 0.0006% THD+N). I find this reassuring, if a little boring!
No surprises there. I used the Alps Blue Velvet pots as frequency and level controls in my low distortion oscillator that measures at something less than 0.002%.
The sound is entirely related to the feel. That's why cello equipment sounds so good , because the 63 way stepped attenuators are so nice to operate.
I like stepped attenuators. I know they don't sound any better, but they are nice to click.
I like stepped attenuators. I know they don't sound any better, but they are nice to click.
The main thing with pots is to keep DC away from them, especially the wiper-track contact. It is astonishing how many designs ignore this, then try to rescue the situation by specifying exotic pots instead of fixing the circuit by adding a few coupling capacitors.
The second thing with pots is to impose a low load (i.e. high resistance) on the wiper output so that the weak point (the wiper-track contact) does not have to drop too much signal voltage even if it is a bit flaky. For this reason law-shaping resistors are a bad idea IMHO.
The second thing with pots is to impose a low load (i.e. high resistance) on the wiper output so that the weak point (the wiper-track contact) does not have to drop too much signal voltage even if it is a bit flaky. For this reason law-shaping resistors are a bad idea IMHO.
So the collective knowledge is that materials make no difference? I have decades of experience to the contrary.
Would you care to share some of that experience? As someone who has in the past fallen into the trap of believing the published guff I am interested.
No, no-one said that. What people have said is that any sensitivity to materials is a symptom of a non-optimum design (e.g. and especially, current through the wiper). This is a separate issue from reliability and environmental suitability, which are very much material-dependent.
decades of experience didn't show you how to solicit information in public forums, understand that you may have tolerate replies from differing perspectives?
Not sure if the OP was asking for knowledge, experience, opinion or just seeking confirmation of his own.Bamalama said:
Conventional engineering seems to be sufficient for high precision test equipment so ought to be adequate for the much simpler task of attenuating a pair of audio signals.
I have had a bigger issue with the 2 sides of the pot matching more than the material having an impact on sound. Drives me crazy when I turn up a pot and 1 side comes up and the other doesn't.
I use stepped attenuators from ebay. Close matching is easier to do with resistors and they're only $20-$25.
I use stepped attenuators from ebay. Close matching is easier to do with resistors and they're only $20-$25.
Well, I didn't receive the information that I was seeking, but I did receive information.
Now that I know the nature of the biases and superstitions of the residents here, I can limit my inquiries to those that are compatible.
Thank you.
Now that I know the nature of the biases and superstitions of the residents here, I can limit my inquiries to those that are compatible.
Thank you.
Hilarious. Science is bias and superstition and vague personal opinions are facts. Did I miss the announcement that it was backwards day?
Member since 2009, it took a while. The OP smells like bait to me and you caught just what you expected.
I have found that measurements sometimes show pot problems, especially the very serious ones, but no easily measurable distortion does not predict that the pot is not identifiable by an expert. For example, Alps measures great, but it is not perfect sounding. However, it is usually available, and that is very important. Whoever asked this question first, asked the wrong people for advice.
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