# Do resistors make a difference in audio quality?



## sputnik13

I'm making plans to build a DIY amp. Starting with the mini3 from amb.org. Does it really make a difference to the sound quality what brand resistor I use?

 I ask because the description for ALO's "double mini3" is claiming to have superior sound quality because they "changed a few resistors in the signal path with a brand that we believe offers a less grainy top-end and has more extension and is more effortless sounding" in addition to having a Black Gate capacitor rather than "stock" capacitors.

 The part list on amb.org says use xicon resistors, but I get the feeling some people think Vishay Dale RNxx resistors are very high quality from some of the posts I've seen touting the fact that they used "the highest quality parts" and listing Vishay Dale. So does it really make a difference? Anyone have first hand experience they can speak from?


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## sputnik13

Oh for that matter, if black gates are so great, why isn't one recommended for use on some of amb.org's designs? I guess that's more a question for amb than the public at large.


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## EFN

Because Black Gate caps are out of commission for a while. The only available stocks now are old leftovers.


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## sputnik13

Quote:


  Originally Posted by *EFN* /img/forum/go_quote.gif 
_Because Black Gate caps are out of commission for a while. The only available stocks now are old leftovers._

 

Does that mean I should stock up on them while I can? 
	

	
	
		
		

		
			





 Any thoughts on the resistor question?


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## fordgtlover

The Mini³ uses mini resistors. I don't think the RN55 resistors will fit properly. As for the black gates in the Mini³, I think it was discussed somewhere that these are not in the signal path, so are unlikely to really improve anything.

 And, for the record, I never thought the Mini³ had a grainy top end.

 The fancy resistors sure do add some bling, but whether they improve the sound is probably a decision you need to make for yourself. Personally, I'm happy using metal film 1% resistor. I often do use the RN55 because it's just as easy to get them when I order other parts.


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## sohels

I would think that the closer a resistor remains to its specified value over a reasonably wide range of temperature, the better it is. So if your build requires closely matched resistors, I guess you should invest in better resistors.

 I do not know much about specific brands though.


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## Beefy

Quote:


  Originally Posted by *sputnik13* /img/forum/go_quote.gif 
_Oh for that matter, if black gates are so great, why isn't one recommended for use on some of amb.org's designs? I guess that's more a question for amb than the public at large._

 

Black Gates are very good for specific purposes. In most cases, this is as coupling caps directly in the signal path. None of AMB's designs have coupling caps in the signal path, thus no need for Black Gates.

 The current habit of throwing Black Gates into everywhere that they will fit is silly. It is a waste of a finite resource now that they are out of production, and in many cases other much cheaper capacitors would be better and more sensible. Unfortunately, sensible choices rarely make for good marketing......


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## sputnik13

Thanks for all the great responses. I'm curious about the RN5x still (I'm not dead set on them or anything, I just want to understand), the RN50 is on the list of alternatives resistors for the mini3 and the RN55 is in the part list for CK2III (which I'm thinking of building after the mini3), so are they in fact superior to other resistors in performance? I've not seen posts anywhere else talking about the difference in sonic qualities of resistors so I was baffled by the aforementioned post that touted using RN55 as use of premium components... I wish I could remember where I read it.


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## Beefy

The whole Vishay Dale RN series are premium components. They are really good resistors at a really good price, and the unofficial default for DIY projects. This isn't to say that other cheaper resistors aren't also an acceptable choice, or that you can't get even better resistors at higher prices.

 But to obsess over such a small point is silly. It is safe to say that if AMB recommends it, he has a reason for it, and it will be an excellent choice.


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## NelsonVandal

IMO Mini3 has a slightly grainy top end and a slightly exaggerated mid. As a whole a bit aggressive. I don't think it has anything to do with design or passive parts. Since amb shows square waves and RMAA tests, we can be absolutely sure the amp has a flawless design and layout. It's just the way AD8397 sounds.

 The placebo effect is very strong when you modify stuff yourself, and especially if you pay serious money for the parts, and even more if the parts look nice. In this kind of topology with an active ground channel, and the opamps running at quite high bias current, capacitors have very little impact on sound quality.

 When it comes to resistor "sound" some claim there's a difference. If there is, it's very minor. IMO it's the active parts that really make a difference, like opamps and transistors, and capacitors if they're in the audio path.


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## rds

Not only can black gates be a waste of money, imo there are superior options for everywhere but (perhaps) the signal path. I would rather go with a cap that has a complete datasheet with specs and tolerances ...do black gates even have a datasheet?
 Black gates are like glow sticks at a rave - people just stick them everywhere in a euphoric delirium (it is fun though) 
	

	
	
		
		

		
		
	


	




 EDIT nice thing about glow sticks is they're cheap. Sometimes I'll put on a glow bracelet just chillin at home


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## FallenAngel

Hold on, I must really be missing something. When did Rubycon start making resistors? Rubycon makes (or "made" but that's questionable always) Black Gate capacitors.

 For resistors, I look at the thermal drift, noise level and tolerance of the resistor and for 99.9% of the time, I use the Vishay/Dale RN or CMF lines of resistors. In the design for the Mini^3, I go with the Panasonic ERO series "mini" resistors, just for their small size and the fact that the design is fairly strict with parasitic capacitance in the resistor leads (read as DO NOT USE VISHAY DALE AS YOU MAY GET AN OSCILLATING AMP).

 Although there is much debate about "audiophile" resistors, unless I want to really go down that road and use PRP or Holco resistors, I just stick with what I know works "best" or at least what is most recommended by those who know "best".


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## Ferrari

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_...
 I use the Vishay/Dale RN or CMF lines of resistors. In the design for the Mini^3, I go with the Panasonic ERO series "mini" resistors, just for their small size and the fact that the design is fairly strict with *parasitic capacitance in the resistor leads *(read as DO NOT USE VISHAY DALE AS YOU MAY GET AN OSCILLATING AMP).... 
	

	
	
		
		

		
		
	


	


_

 

Can you elaborate a bit more on that "parasitic... thing" ???


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## fordgtlover

Quote:


  Originally Posted by *Beefy* /img/forum/go_quote.gif 
_snip...

 It is safe to say that if AMB recommends it, he has a reason for it, and it will be an excellent choice._

 

 Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_snip...
 I just stick with what I know works "best" or at least what is most recommended by those who know "best". 
	

	
	
		
		

		
		
	


	


_

 

 Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_snip...
 When it comes to resistor "sound" some claim there's a difference. If there is, it's very minor. IMO it's the active parts that really make a difference, like opamps and transistors, and capacitors if they're in the audio path._

 

It is unlikely, IMHO, that you will find better advice on this matter.


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## Earwax

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Can you elaborate a bit more on that "parasitic... thing" ??? 
	

	
	
		
		

		
		
	


	








_

 

Not because the resistors are bad, but because they are too large to fit the board and to mount them they have be "tombstoned" with one long lead and it's the long lead that can cause problems. [unwanted inductance (not capacitance) according to AMB's mini3 page]

 I can see high-spec resistors making a difference in a high current/high heat application. But in a battery powered amp? 

 I once built a cmoy with carbon film resistors instead of metal film, just to see what would happen. It really did sound bad.


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## tomb

PRP resistors have been touted as the audiophile version of V-D's. They also have a cool red color.

 However after using them extensively, I got fed up with the wildly inconsistent epoxy coatings as compared to V-D's - different shapes, different sizes, easy to break, etc. I could also never tell a difference in sound quality from V-D's. In short: Unless you like the color (
	

	
	
		
		

		
			





) just use V-D's and stay away from PRP's.


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## cobaltmute

cMF50 Vishay Dale's supposedly fit in the Mini^3. 

 The I find interesting is the so many want the RN series Vishay over the CMf's but per the datasheets they are exactly the same.


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## Uncle Erik

Quote:


  Originally Posted by *sohels* /img/forum/go_quote.gif 
_I would think that the closer a resistor remains to its specified value over a reasonably wide range of temperature, the better it is. So if your build requires closely matched resistors, I guess you should invest in better resistors.

 I do not know much about specific brands though._

 

This. You want stability.

 This is the reason why some people think their gear sounds better after warmup or having been left on 24/7. The heat makes the components drift in value which changes the sound. It's not so much "better" as the values have changed. Carbon comp resistors are the worst for this. Personally, I like the Vishay-Dale, too. They're stable, have tight tolerances and don't drift much.

 I've used a few of the boutique resistors, but didn't think they were appreciably better than the Vishay-Dale, though being several times more expensive. Same with caps - I still like and use Orange Drops as often as possible. I've dropped several hundred of them into old radios and have never had a failure or problem.


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## amb

For the Mini³ , all the recommended resistors (Xicon MF-RC, Panasonic EROS2, Vishay-Dale RN50 or CMF50, Multicomp MF12) are 1% metal film with 50ppm thermal stability, so they are all good. Choose whichever that is most convenient for you.


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## sputnik13

Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Hold on, I must really be missing something. When did Rubycon start making resistors? Rubycon makes (or "made" but that's questionable always) Black Gate capacitors._

 

I wasn't implying that Rubycon makes resistors, I thought it'd be obvious if I said "Black Gate" that I'm referring to capacitors as it seems most people on here are knowledgeable about that.

  Quote:


  Originally Posted by *FallenAngel* /img/forum/go_quote.gif 
_Although there is much debate about "audiophile" resistors, unless I want to really go down that road and use PRP or Holco resistors, I just stick with what I know works "best" or at least what is most recommended by those who know "best". 
	

	
	
		
		

		
		
	


	


_

 

I don't know what works "best" and that's why I'm asking all these questions 
	

	
	
		
		

		
		
	


	




 I appreciate what you said about the Vishay Dale, but I think a few people overlooked that I mentioned RN50 (not RN55) is on the list of resistors recommended for the mini3 on amb.org's page (way below in the "resistor" section below the table of parts), which is why I was still asking for more clarification. I'm going to go read up on what "parasitic capacitance" is now


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## sputnik13

Quote:


  Originally Posted by *Uncle Erik* /img/forum/go_quote.gif 
_This. You want stability.

 This is the reason why some people think their gear sounds better after warmup or having been left on 24/7. The heat makes the components drift in value which changes the sound. It's not so much "better" as the values have changed. Carbon comp resistors are the worst for this. Personally, I like the Vishay-Dale, too. They're stable, have tight tolerances and don't drift much.

 I've used a few of the boutique resistors, but didn't think they were appreciably better than the Vishay-Dale, though being several times more expensive. Same with caps - I still like and use Orange Drops as often as possible. I've dropped several hundred of them into old radios and have never had a failure or problem._

 

Thanks for that information, so I take it I need to look for stability more than anything else with resistors.

  Quote:


  Originally Posted by *amb* /img/forum/go_quote.gif 
_For the Mini³ , all the recommended resistors (Xicon MF-RC, Panasonic EROS2, Vishay-Dale RN50 or CMF50, Multicomp MF12) are 1% metal film with 50ppm thermal stability, so they are all good. Choose whichever that is most convenient for you._

 

Ah, you mentioned something that I wasn't seeing anyone else mention, 50ppm thermal stability. I was wondering what that means. I'd looked for it online but haven't really found any information on what the number means, as in is lower better or is higher better. All the descriptions I'd found assume you already know what that means and just talk about what color band on the resistor implies what value.

 Oh, thanks so much everyone for all your valuable feedback. I know on the one hand I could just build something with the parts recommended in the parts table on amb.org and most likely I'll be satisified with the sound, but I'm just interested in understanding as much as possible about everything that goes into the build and the reasons why. I do try to find information on my own but this is one subtlety that I've not found much information on so far, so thank you for entertaining my questions


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## amb

More precisely, it's a temperature coefficient expressed as ppm/°C (parts per million per degree Centigrade). 1ppm/°C is equivalent to 0.0001%/°C, so 50ppm/°C is 0.005%/°C. Over an operating temperature range of, say, 10-40°C, these resistors' resistance will not vary by more than 0.15%.

 Not that the Mini³ circuit actually require that kind of thermal stability, but suffice to say that all the recommended resistors are excellent in this regard.


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## dhp

that whole resistor business sounds like BS to me if he's still using metal film resistors.


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## Beefy

Quote:


  Originally Posted by *cobaltmute* /img/forum/go_quote.gif 
_The I find interesting is the so many want the RN series Vishay over the CMf's but per the datasheets they are exactly the same._

 

I like the RN series because they are dirt cheap at Mouser


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## mb3k

Also, IIRC aren't the Vishay/Dale's rated higher than they're stated on the package? ie. a 1/4W Vishay/Dale RN can be placed in a 1/2W position with no worries.


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## amb

Quote:


  Originally Posted by *mb3k* /img/forum/go_quote.gif 
_Also, IIRC aren't the Vishay/Dale's rated higher than they're stated on the package? ie. a 1/4W Vishay/Dale RN can be placed in a 1/2W position with no worries._

 

Only because RN is "mil-spec", and subject to a more stringent rating requirement. The equivalent CMF resistors are rated double the power.


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## fzman

Some time ago, I built some passive line-level crossovers between preamp and amps so I could biamp. The crossover circuit uses two caps and two resistors, and is very much in the signal path. I tried a variety of caps, and settled on the auricap teflons. Resistors were also auditioned, including shinkoh tantalums, prps, vishays (black bodies from parts connexion), caddocks, rikennohm carbon films and finally the texas component baked vishay tx2532 (i think that's the number). there were definite sonic differences between them-- the texas components ones are the ones currently in there. are they 100 times better-- no! are they better-- yes! Would i replace 15 or so resistors in my signa22 psu with $8@ of these-- NO!

 in the signal path, with a highly resolving system, I think these are worthwhile-- I've got some of the new z-foil variants on the way for my headphone amp (uses on two resistors per channel; feedback and input).

 we shall see.......


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## BobMcN

The right resistor in the right spot can make as much difference as the right capacitor in the right spot. But not all caps nor all resistors need to be "audiophile" quality.

 Bob


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## Ratzilla

Quote:


  Originally Posted by *BobMcN* /img/forum/go_quote.gif 
_The right resistor in the right spot can make as much difference as the right capacitor in the right spot. But not all caps nor all resistors need to be "audiophile" quality.

 Bob_

 

I agree.

 When resistors are made, they have a tolerance. For example, a 15k resistor can be anywhere from 14k-15k. The more expensive resistors will have a better chance of being close to 15k. If you get 10 5% resistors, you might get a few that are 14990 and a few that are 14500. If you get 10 1% resistors, you might get a few that are 14990 and a few that are 14850. In other words, they will be better but if you get lucky or manage to get some 5% resistors that are close to 15k, they will be as good as 1% resistors that are close to 15k


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## guzzler

Quote:


  Originally Posted by *Ratzilla* /img/forum/go_quote.gif 
_I agree.

 When resistors are made, they have a tolerance. For example, a 15k resistor can be anywhere from 14k-15k. The more expensive resistors will have a better chance of being close to 15k. If you get 10 5% resistors, you might get a few that are 14990 and a few that are 14500. If you get 10 1% resistors, you might get a few that are 14990 and a few that are 14850. In other words, they will be better but if you get lucky or manage to get some 5% resistors that are close to 15k, they will be as good as 1% resistors that are close to 15k_

 

That's technically true, but not relevant at all. Firstly, 5% (generally carbon) resistors in small quantities are the same price as 1% metal film resistors. You can also pay vast sums for "audiophile approved" resistors that in terms of specs went out in the 1970s. Secondly, many resistor positions rely on ratios rather than absolute values. This is the case for all resistors in the mini3. So, it doesn't matter what the absolute value of a single resistor is, rather the ratio of two. 

 Some resistors will be low inductance, higher power, better tempco etc. These are picked for specific and demanding jobs, not those encountered at very low powers. In general, I would doubt in such a simple design you will hear any difference between reasonable quality metal film resistors and things much more expensive. If you don't mind paying a extra pound or two, go for it, it won't do any damage, but you won't miss out on anything if you don't.


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## Fin1211

what about the extended runtime one(that doesnt use the ad8397)?
  
  Quote: 





nelsonvandal said:


> IMO Mini3 has a slightly grainy top end and a slightly exaggerated mid. As a whole a bit aggressive. I don't think it has anything to do with design or passive parts. Since amb shows square waves and RMAA tests, we can be absolutely sure the amp has a flawless design and layout. It's just the way AD8397 sounds.
> 
> The placebo effect is very strong when you modify stuff yourself, and especially if you pay serious money for the parts, and even more if the parts look nice. In this kind of topology with an active ground channel, and the opamps running at quite high bias current, capacitors have very little impact on sound quality.
> 
> When it comes to resistor "sound" some claim there's a difference. If there is, it's very minor. IMO it's the active parts that really make a difference, like opamps and transistors, and capacitors if they're in the audio path.


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