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68.54.136.2
I'm using carbon film resistors on an audio test project. Some of my resistors are from Radioshack and others are from Mouser. the Mouser ones are labeled Made in Thailand and other foreign countries. All are carbon films 1/2 watt.
But the Mouser ones, and this is NOT a statement against Mouser!!!! all sound gritty, muffled and just plain bad. Where the Radioshack ones sound fine.
Is that really possible?
charles
Follow Ups:
If you have an open mind and a tweaky system you can easily do a straight wire bypass test on a resistor. Just use a one half inch piece of solid core straight wire added to the output of a low impedance source (preamp or DAC or phono stage). Mount the one half inch piece of wire directly to the output jack. Please make sure the output impedance on your source is low (1-200 ohms max). Listen wth this extra piece of wire and then substitute a 10 ohm resistor of your choice. The 10 ohms will not make any difference in capacitance roll off or such....what you will hear is the difference between the straight wire and the resistor (both have the same number of solder joints in series as well). Now you will have some knowledge of how resistors sound (every brand of resistor in the world sounds different). There is no resistor that has ever passed this test.....the latest nude Vishays and some other surface mount nichrome resistors are closest. The only real knowledge is experiential. If you are not willing to listen then you are just experiencing and expressing your belief system (opinion, no real knowledge).
Edits: 09/15/14 09/15/14
Sounds like a fun test. One day I will wire up that setup and try it. Maybe figure out a way to use my scope to see wave changes.
I'm not a picky person. but I do know when I hear crap.
thanks
charles
Yes.
It depends upon where in the circuit they reside.
...CC resistors can sound laid back and/or muffled.
in trying Vishay,PRP and so on is they all sound at least a little different. I actually now prefer an Allen Bradley carbon mil spec resistor in analog circuits. Less strident on top.
ET
Those are carbon composition resistors, not carbon film. Carbon comp might not be the best choices where accuracy and low noise are required. They could be used for their euphonic qualities, but I would never suggest them to a novice.
Peace,
Tom E
I didn't say they ere carbon film I said they were my preference. Everyone gets to decide in a free world. : )
ET
I was actually speaking of carbon composition resistors. They're sure a LOT of types of resistors suitable for audio work.
Carbon comps must be baked prior to use to drive out the moisture they have absorbed over the years.
The shock from soldering will alter the resistor permanently if you don't bake it first.
I keep my spare resistors and caps in a sealed plastic tub with about 200 silica gel packs. I always felt that good enough. What do you think?
ET
I work in an aerospace concern, we bake them.
A while back we bought Allen Bradley so we could stock up on carbons (after they had discontinued them).
I suppose if they were dry enough to start out with your method makes sense.
I would give some thought to a bake after buying them, and then use your method for storage.
That is quite interesting. What do you use carbon composite resistors for in the aerospace industry? How do you bake them? Is it something you could do with a kitchen stove?
Dave
"What do you use carbon composite resistors for "
RF in older designs.
" Is it something you could do with a kitchen stove?"
Sure, preheat oven to 150°F, bake for 1hour, then raise to 250°F for an hour, allow to cool and use right away or store with desiccant.
The sudden shock of a soldering iron on a resistor with a lot of moisture permanently changes the value, baking avoids this.
It would have to be an electric stove. Burning natural gas produces moisture.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
What temperature?
TIA!
Dave
I don't know.
In the studio we used to bake audio tape at 130 degrees.
I've never baked resistors.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Interesting! I have some R2R tapes, but none are shredding.
Dave
Its mainly back coated tape that needs to bake to soften up the lube.
Thanks! Great idea!
ET
Congratulations on passing your critical listening test. Every component in the signal path, and many in shunt positions or the power supply, can affect the sound.
I have experimented with a dozen or more types of resistors in my own power amps and active filters. The resistor that affects the sound the least is called a Z-foil naked Vishay. It is crazy expensive for something as simple as a resistor, but it is the ultimate in purity and accuracy, if that's what you really want. You cannot buy them at Mouser, but only from parts specialists such as Parts Connexion or the manufacturer, Texas Components.
As a general rule, carbon film resistors tend to smooth out details while presenting a more musical sound. Metal film resistors are more accurate, but can contribute to stridency, especially if they have magnetic leads or end caps, as most cheap parts do. Of the mass market stuff, I would stick with Vishay/Dale, which are non-magnetic. They cost only a few cents more than the cheapest metal films, and are well worth it. A bit more exotic, but still reasonably priced with very good sound, is PRP, made in USA, which are used by some premier equipment manufacturers. Not sold at Mouser, but at Parts Connexion and Sonic Craft. Yet another step up would be Caddock MK series. There are plenty of others, but these are the basic, best value parts. The "best" resistor does not always sound the best at every place in a circuit. It is a lot of fun to buy a few different types of the same resistance and experiment. Resistors take only a few minutes to break in, so your testing can proceed rapidly. You will be surprised by how much one tiny part can affect your system.
Peace,
Tom E
Words like "accuracy" and "neutral" used to describe hifi parts/equipment seem to be just a matter of the ear of the "behearer" to me, unless you're referring to some kind of electronic test results - and I dunno what that'd be.I'm a technical ignoramus, so correct me if I'm wrong, but......
If a resistor is required at some point in a circuit and you can't hear, say, preamp X without that resistor, when you put various resistors in that position how can you judge that resistor Z has no effect on the sound, or is more "accurate" than resistor Y?
I'm not claiming there's no difference in effect on sound, but I'd think its just a matter of preference rather than being able to determine one is more "accurate" or "neutral" than another.
Edits: 09/11/14
Which part sounds more like real music? That is the ultimate reference. All my experiments are done by listening, with no technical testing involved. Of course, that means my results are purely subjective. I believe that can still yield decent conclusions if comparisons are made impartially, which is not easy. If a component colors the sound, it is not accurate. The naked Vishays have a very solid reputation and specifications superior to other resistors, and I have determined that, in many positions in a circuit, they are indeed the best (very likely the most accurate) parts available. Of course, that doesn't mean everyone will like them, but most people do.
Peace,
Tom E
In the end its a subjective issue, and one man's "neutral" is another man's "unnaturally threadbare", one man's "naturally rich/warm" is another man's "muddy". For example, the tech I use (Ben Jacoby, pretty good rep) thinks Vishays sound terrible. IIRC he much prefers tantalum resistors, and maybe some types of carbon too.
As I said, so far I'm too ignorant to make my own judgment, but hope to rectify that in the near future. Thanks for the reply.
Carbon films should be almost as good as metal films, maybe a tad more noise, but it shouldn't be audible. I never bother with carbon film because good metal films are so cheap. It's so difficult to make a comparison between resistors that I discount almost all reports of audible differences between types.The metal foil resistors aren't all they're cracked up to be- go read what the Audio Precision people have to say after testing them recently.
Carbon composition is unstable so some might be pretty good, but they can be very noisy and the values drift. They have no place in modern design. Some say they're lower inductance, but if you have any lead length at all, that benefit quickly disappears. Put a standard 1/4 W metal film on a vector impedance analyzer and you'll see it does fine at 50-100 MHz. Metal oxide can give you a very small resistor (that can run burning hot) but their temperature coefficient is lousy. I avoid 'em.
In SMT, thick film resistors are a lot noisier than thin film (metal film).
There are no sonic properties of resistors that aren't apparent from measurements of voltage coefficient, noise measurements and maybe temperature coefficient. It's also highly debatable if magnetic end caps or leads have any audible effect, though material types might give you some small thermocouple effects. Again, the tests to prove it are far too hard for people to set up. You'd have to build up truly identical units to compare and few are willing to go to that trouble, then you still have all the issues of doing an unbiased comparison between two devices.
It turns out that you get a huge bang for your buck with common 1/4 W metal films from KOA or whoever.
(It's OK, I do have several pairs of flameproof underwear at the ready.)
Edits: 09/11/14
Some of your post makes sense, some of it is mere techno babble. One cannot measure what a component, even a resistor, sounds like. TC and noise are important, but they do not determine what a part sounds like. Comparable values do not always produce comparable sound. End of story, for me. I think most people post in this forum because they are interested in what improves sound, not what has better measurements. Too bad you discount reports of audible differences before even trying for yourself. Try swapping resistors in the feedback loop of an opamp. Then put away your vector impedance analyzer and listen.
Yes, carbon comp sucks for audio for the reasons you cited. Yes, the difference between carbon film and metal film is minor. I have HEARD very good and very bad examples of each. I really don't care how they measure, other than accuracy of value, which can be selected if 1% spec isn't sufficient.
No, it's not easy to test parts. I have spent A LOT of time doing it, and I have heard differences.
KOA resistors have magnetic end caps, and don't sound very good to me in unbiased testing. I did not even know they were magnetic until after I listened to them, but I knew something wasn't right.
I do not claim to have golden ears, but I am not afraid to use the average ones I've got to draw conclusions.
Peace,
Tom E
I used vishay bulk foils/z foils for many years. But some time ago I came to the belief that current production doesn't sound as good as older production (say more than 10 years ago). I noticed this originally when building a DAC and using such resistors as IV components.
Searching for an alternative I came across Neohm ultra precision wirewound (UPW), similar price to Vishays. Good specs - 3ppm temp coeff, very low noise, Imho, these sound superior to current vishays and even older vishays. Downside is that they are not available in the complete range. But recommended for critical locations. Just my $0.02
Are those readily available?
TE
Of course you can't measure what anything sounds like, but you can measure a bunch of other things and make a pretty good prediction. Those "other things" are very well established and understood, and can be measured to far higher resolution than any ear can discern. People are always looking for some "factor x" that hasn't been discovered, but affects how things sound. So far there's no evidence that it exists.Identical signals sound identical. Build two circuits, one with your favorite resistor and one with resistors you consider junk. Feed 'em the same signal, the music of your choice, and do a differential measurement of the outputs. If you see something, now you have something to investigate. If not, regardless of subjective opinion, there is no audible difference between the parts. It's really that simple.
Edits: 09/12/14
Yes, identical signals sound identical.
Signals that are not identical do not sound identical.
What is your point, other than that you believe everything that can be heard can be measured? The X factor of sound has not been found to be measured yet, so it does not exist. All SS amplifiers measure the same so they all sound the same. You're really in the wrong place here.
Peace,
Tom E
Well, yes, you're probably right on most points, other than solid state amps. They certainly don't all measure the same, nor do they sound the same. Do you have any reasons that different resistors would sound different? Anything testable or provable beyond a reasonable doubt?
I was being facetious about SS amps. Whether or not they measure differently, many do sound different.
I wish I had even a clue as to why such little resistive bits can make a difference. Someday, maybe an enterprising researcher will uncover a new way to measure the aesthetic qualities. Until then, I'll take existing specifications into consideration but always let my ears finally decide.
Some people insist that resistors are directional, but that's where I draw the line. I simply cannot conceive how the current flow can be different in one direction versus the other. I think they do hear something, but I believe it has more to do with the part "settling" somehow and will change back after a short time. I have heard it with speaker wire and IC's. After a few minutes of conducting, both directions sound the same to me unless there is an actual physical difference between the two directions.
Peace,
Tom E
Do you have any reasons why various resistors should sound the same? After all they all have different values for their measurable parameters such as Temp Coeff, Voltage and Frequency dependent changes in resistance, parasitic inductance and capacitance, modulation noise, thermal noise, etc.
For instance : Given that some resistors have TCr of 1ppm and others 1000ppm, and that this parameter directly affects one of the chief non-linearities (ie distortion mechanisms) of resistors, thermal modulation, please explain why you think that such different resistors would sound the same?
Also people also have tried and found audible differences between various types of resistor, and it's no coincidence that the top rated resistors usually have a very good TCr (eg zfoil 0.02ppm). So the all-resistors-sound-the-same argument is looking shaky imho.
I do not have a reason. I'm sure TC and other measurable specifications are a factor, but there seems to be something beyond that. Similar types, say MF with identical specs, do sound different. Magnetic properties may play an important role.
I wouldn't expect a resistor with 1000ppm TC to have a place in modern audio equipment.
By the way, have you read through the entire thread? You seem to have the wrong impression of my statements.
Peace,
Tom E
I should also mention that it's horses-for-courses when it comes to resistors. (As with all components). Sometimes low noise is paramount. Sometimes low distortion due to TCr. And sometimes what you need is really low inductance (eg grid stoppers, gate stoppers), in which case, carbon films can be the best. Blindly replacing all your resistors with zfoils is not necessarily going to lead to audio nirvana.
I wasn't really suggesting that blindly replacing all resistors in any circuit with only Z-foil was the path to nirvana, but it could be a path to the poorhouse. I use about six different types in my little chip amps, and I've tried many more. I can't pretend that what I have is the optimum configuration, as there are simply too many possible combinations. But what I use now was determined to be the "best" after MUCH experimentation.That was my initial suggestion: buy a few types and experiment. The OP determined by accident that resistors sound different. I agreed, and suggested he try others.
I think you meant carbon comp, not carbon film for low inductance. Even then, there are probably better choices.
Peace,
Tom E
Edits: 09/12/14
Long ago I designed an amplifier (non-audio) that ran quite high voltages. It had linearity issues that I eventually traced to some MOX resistors. I'm not sure if it was tempco or voltage coefficient, but I've been wary of them every since, though they're probably fine in supply, loading or non-signal related locations.
In a different application some thin film SMT resistors were replaced with cheaper thick film. The noise increase made the circuits useless. You guessed it, I've been wary of them ever since. Again, they're appropriate in many spots, but not in my audio circuits.
Having replaced bunches of carbon comps that drifted high in value or became crazy noisy over the years, I can't see using them except as a special effect. Once they drift, I haven't seen baking bring them back. IMO, desiccant storage is probably a very good idea.
Those are all real measurable effects. What I haven't seen is any artifact resulting from the use of decent metal films (or foils) that would lead me to believe an improvement could be had. I could fault (or praise) them in a DC metrology application for ppm level drifts or changes in value from soldering or the generation of thermocouple voltages, but those things just don't show up in (my) audio applications.
In a solid state amp the two most important resistors are probably the feedback resistors, as any imperfection there becomes a fundamental part of the amp performance. Those, and the input stage, are where the right parts probably make the most difference. Carbon comps aren't suitable, wire wounds aren't suitable, thick film isn't suitable, MOX isn't suitable, so what does that leave us? Metal film and foil. Then it's just a question of what brand and specifications.
why aren't wire wounds suitable?
Wire wounds are extremely quiet stable resistors, but being wound they do have some inductance. Even "non-inductive" winding patterns can't cancel it completely. Now, at audio frequencies this inductance is rarely an issue. The problem is that our circuits and devices often have far greater bandwidth than audio. As an example, the best audio opamps often have gain bandwidth products of tens of megahertz. Power amps may have response at hundreds of kilohertz. Keeping those circuits stable and well behaved requires thinking about component characteristics far outside the usual audio bandwidth. I spite of that, wire wounds can be used to good advantage in many locations, just not where a bit of inductance could cause instability.
I've read that it can act like a coil and cause high frequency problems?????? At least thats the poop in the speaker world.
charles
Well yeah a wire wound on a coil forms an inductor. That being said, metal and carbon film resistors have their conductive element flashed on a ceramic core and the element is laser etched in the form of coil too. The construction is similar in that wayOf course there are non inductive wirewounds and non inductive film types also.
Edits: 09/13/14
Especially as Emitter followers.
Yes. It would be of interest to learn more about resistors, as used by companies like, Conrad Johnson, ARC, Jeff Rowland...etc.
I had the same eye opening experience, also in a preamp. I was making some mods, had the vaue I needed in a nothing special carbon resistor. I changed it out, same value, and it truly was the resistor.
The designers strategy was to dull the highs in order to smooth out the sound. I found that better caps in the power supply allowed me to use metal films and achieve a much more cleaner, resolving sound. I would NEVER use carbon film for any audio work unless there was a specific reason other than 'dulling' the sound.
How large (in watts) do you need.
For simple test purposes Radio Shackup sells film resistors in 1/4 watt.
For the high-priced stuff?
Try Vishay-Dale.
Too much is never enough
1/4 to 1/2 is fine
RS doesn't carry metal film
I'm using it for an audio line level
Don't use cheap metal films with magnetic end caps (for sorting convenience?). If you want the best, go for Vishay metal foil. They are expensive but neutral and good sounding. You can often final good value on eBay.
for a cheap experiment? RS is probably OK.
The Vishay / Dale is still probably the best easily available resistor.
Too much is never enough
Well, you have determined that they can. For that matter you have also determined that it's an implementation issue.
While the latter is always a risk metal films are far and away your best bet because they have much less excess noise.
Rick
Thanks, I thought I was being crazy. Every time I used those resistors - geeze it sounded awful.
After I finish tweaking, what resistors do you recommend? It is for a line level attenuator type setup. Low voltage stuff but audio important.
charles
I can't really recommend any particular brand from recent experience. Caddock is probably the oldest supplier as I remember using their parts in the 60's so I'd probably look at them or just go with a generic.
Have fun, Rick
Yes
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