Each persons having different opinions of different types of resistors, I decided to try them myself. I'd like to AB Metal Film, Metal Oxide, Carbon Composition and Carbon Film types.
For that, I'll use a pair of AKG headphones, a CD player and a *simple* headphones amp - where the different resistors will be tested.
To hear the sound of the resistors, I suppose I need to put an high value resistor in the signal path. But, what for the rest of the circuit? 😀
BTW, simple means something similar to this:
http://www.geocities.com/tomzi.geo/2tr_amp/2tr_amp.htm
For that, I'll use a pair of AKG headphones, a CD player and a *simple* headphones amp - where the different resistors will be tested.
To hear the sound of the resistors, I suppose I need to put an high value resistor in the signal path. But, what for the rest of the circuit? 😀
BTW, simple means something similar to this:
http://www.geocities.com/tomzi.geo/2tr_amp/2tr_amp.htm
That circuit won't take you where you want to go. To list just two problems, the capacitors will influence the sound more than the resistors under test. And the biasing arrangements are flakey to the max. That is the sort of circuit you saw in the earliest transistor days, when circuit design was still influenced by tube design.
I'm not an expert on headphone amp design, but over at Head-Fi Forums there are many.
Being mildly compulsive, I would change all the resistors in the circuit; but changing the feedback resistor pair will have the greatest effect. However I'd actually use a different approach. I'd make a 20 dB amplifier, probably using one of the Burr Brown/Texas Instruments 2604 family (look for the opamp-rolling articles) with a 20 dB multistage attenuator -|-|-| and not change your headphone amp circuit at all. I'd use Vishay bulk film resistors, from Michael Percy, for the amplifier circuit, and the attenuator would be made up of the resistors under test.
For an inverting circuit, and purchasing convenience, I'd use series 10K, Shunt 10K, series 10K, Shunt 10K, series 10K (into the amp inverting input) and feedback of about 80 K around the amp. This will increase the effect of the resistor type. I'd insert this in series with your headphone amp input, and your headphone amp of course needs to be as good as you can manage.
I'm not an expert on headphone amp design, but over at Head-Fi Forums there are many.
Being mildly compulsive, I would change all the resistors in the circuit; but changing the feedback resistor pair will have the greatest effect. However I'd actually use a different approach. I'd make a 20 dB amplifier, probably using one of the Burr Brown/Texas Instruments 2604 family (look for the opamp-rolling articles) with a 20 dB multistage attenuator -|-|-| and not change your headphone amp circuit at all. I'd use Vishay bulk film resistors, from Michael Percy, for the amplifier circuit, and the attenuator would be made up of the resistors under test.
For an inverting circuit, and purchasing convenience, I'd use series 10K, Shunt 10K, series 10K, Shunt 10K, series 10K (into the amp inverting input) and feedback of about 80 K around the amp. This will increase the effect of the resistor type. I'd insert this in series with your headphone amp input, and your headphone amp of course needs to be as good as you can manage.
Will you be setting up a mechanism to switch the resistors without you seeing which is in the circuit? Will you be listening to more than a single sample of each brand/value? And will this test occur with statistically significant sampling? If not, save yourself the time and effort, and us the undoubtedly long rambling account of the test and just tell us which resistor you think looks nicest...
I_F
I_F
At the very most, even if you detect some difference in the "sound" of some resistors, it is going to be at most very subtle. Will it allow you to predict anything? Will your results be applicable to every batch of resistors made by all the manufacturers? Will it apply to every resistor in every circuit, or just to certain types of positions (opamp feedback, for example)? Will the result be valid for all types of circuits or even all circuits of the same type?
I'm not meaning to be cynical. It's just that doing a test like this properly (whatever THAT means) requires so much time and energy, and the results are of such limited applicability, that it seems to me that it would be far better to spend the time studying electronics and learning something of value instead. Get a copy of "The Art of Electronics" and study it. You'll learn many far more valuable things from it in an hour than you will by listening to every resistor in the world.
In spite of what the marketing guys tell you, audio is not magic. It is engineering.
I_F
I'm not meaning to be cynical. It's just that doing a test like this properly (whatever THAT means) requires so much time and energy, and the results are of such limited applicability, that it seems to me that it would be far better to spend the time studying electronics and learning something of value instead. Get a copy of "The Art of Electronics" and study it. You'll learn many far more valuable things from it in an hour than you will by listening to every resistor in the world.
In spite of what the marketing guys tell you, audio is not magic. It is engineering.
I_F
It's your time, money, interest and above all your hobby. I'd suggest enjoying it in any way you wish.
And this does make a nice little project to learn a bit about electronics too.
"The Art of Electronics" will take you as far, and as fast, as you wish to go.
And this does make a nice little project to learn a bit about electronics too.
"The Art of Electronics" will take you as far, and as fast, as you wish to go.
I_Forgot said:
Oh my, what a soap box!
I once changed a single resistor in a conrad johnson tube preamp and heard a difference for the better. Resistors add measurable noise and so far as I've lately understood, noise ain't music. Ask Mr. Vishay, he could probably tell you.
DragonMaster, do do your test. Ain't no measuring equipment anywhere can tell you, in the final instance, and for subtleties like resistor sound, whether an audible change may have resulted, "audible" being the key word. And, hey, if you also read The Art of Electronics, you'll have an edge for knowing to correlate ears to EE sense.
No, I'm not going to use ABX. I've heard bad things about all of them and think that they all sound the same so I don't think it's necessary.
chipco3434 said:
I just realized what this means! Very good! Hah! 😀
DragonMaster said:
In this case I don't know whether you are trying to be funny or not... if you are, VERY GOOD! If you aren't, well...
TD
Here's some info for you on resistor noise:
http://www.vishay.com/docs/63000/7reasdis.pdf
see reason number 5 for an explanation of differences in noise due to resistor material.
They make the unfortunate statement that bulk metal foil resistors are "noise-free" which isn't true. They are noise free only in the sense that they do not exhibit noise in excess of the Johnson (aka thermal) noise which is a function of temperature and resistance.
See explanation of resistor thermal noise here:
http://tinyurl.com/dop9k or in many other locations around the web.
I_F
http://www.vishay.com/docs/63000/7reasdis.pdf
see reason number 5 for an explanation of differences in noise due to resistor material.
They make the unfortunate statement that bulk metal foil resistors are "noise-free" which isn't true. They are noise free only in the sense that they do not exhibit noise in excess of the Johnson (aka thermal) noise which is a function of temperature and resistance.
See explanation of resistor thermal noise here:
http://tinyurl.com/dop9k or in many other locations around the web.
I_F
It's impressive you're researching the matter: *that* is scientific. "Noise free" likely is marketing bravado based on the market position of having the quietest resistor on the market. Vishay's parents were killed in the Holocaust, subsequent to which he set out to design the best resistor to, among other things, contribute in the build of machines, like missile guidance systems, that could fortify, among other things, the Israeli homeland. Very interesting story of dedication.
😉
😉
Here is an interesting paper on 1/f noise (the type that varies depending on the resistor material). It's a weird link, you should save the file and it will have a .htm extension. Then change the extension to .pdf and you'll be able to open it and read it. I guess they have a problem on their web page.
http://arxiv.org/pdf/physics/0204033
I_F
http://arxiv.org/pdf/physics/0204033
I_F
Gonna have some reading to do.
By the way, I test the "resistor sound" for tube equipment. Maybe transistors are not a good choice for this?
By the way, I test the "resistor sound" for tube equipment. Maybe transistors are not a good choice for this?
Difficult question. You need a very good, clean, test setup; good 'phones, amplification, cables, CD player/turntable, and source material. You need a stable system, one that you are well acquainted with, and source material you know well. Really well. The major difference I hear in resistors (if I hear any) is that some are hashy, or coarse in the upper midrange, so your system needs to be clean in that region. Basically, I find that resistors fall into "good" and "not good" categories; I did not hear a difference between the dipped and boxed Vishay bulk films, and the Holcos. I did hear a difference between metal films and carbon composition. In crossovers, I hear a big difference between the inexpensive cast "concrete" and the far better Mills.
Being a transistor type myself, I can't even begin to suggest what tube amplification would meet your requirements. However, if your system does not meet the above requirements, I'd suggest working on that first.
Being a transistor type myself, I can't even begin to suggest what tube amplification would meet your requirements. However, if your system does not meet the above requirements, I'd suggest working on that first.
Well, I don't think that a good system is necessary, as long as a difference can be heard. Even if the system would always sound harsh during testing, I would just pick the one that sounds the best.
But I think that there's a bigger difference with the resistor typewith tubes, because there are some metal-film resistors that can't be used because they're inductive. Thermal noise matters more also because it's getting hot in tube amps.
Also, I heard some people telling that it depends of the type of sound. CC is supposed to sound like vintage equipment but is noisier, while metal film is less noisy, but harsh and sounds like new equipment(makes part of them also).
What do I prefer? I like the tone of vintage equipment but also the "clean" sound from new amps. Some say metal oxide is between both, but getting a metal oxide with a working voltage of 500VAC from 160kohm and up is hard to do.
I guess Xicon goes in "not good"? (Just want to know because I'm not going to get resistors more expensive than 60¢ each.)
But I think that there's a bigger difference with the resistor typewith tubes, because there are some metal-film resistors that can't be used because they're inductive. Thermal noise matters more also because it's getting hot in tube amps.
Also, I heard some people telling that it depends of the type of sound. CC is supposed to sound like vintage equipment but is noisier, while metal film is less noisy, but harsh and sounds like new equipment(makes part of them also).
What do I prefer? I like the tone of vintage equipment but also the "clean" sound from new amps. Some say metal oxide is between both, but getting a metal oxide with a working voltage of 500VAC from 160kohm and up is hard to do.
I have not tried Xicon, so cannot speak to that. Most metal and carbon film resistors have a spiral cut in the deposition, so most are inductive to some degree. You might want to calculate the inductance, using one of the coil calculators on the net. A rule of thumb that I use is to avoid ferrous (magnetic) leads, and if possible, end caps.
If the system has problems of its own, it may well mask what you're listening for.
If the system has problems of its own, it may well mask what you're listening for.
In choosing resistors there are two main types of noise, thermal/blackbody noise and current noise. As far as I know, besides affecting the temperature of the resistor, there is no way to reduce the blackbody noise. Current noise is extremely variable though. Carbon Comp resistors have absolutely terrible current noise while metal foil resistors are very good.
Carbon comps were used for a loing time, and still are for the more "vintage" sound they give. They have other semi desirable properties that keep them in use here and there. Mostly though, anything where noise is a large performance factor, metal foil reigns surpreme.
Carbon comps were used for a loing time, and still are for the more "vintage" sound they give. They have other semi desirable properties that keep them in use here and there. Mostly though, anything where noise is a large performance factor, metal foil reigns surpreme.
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