# metal vs carbon resistors, what is the difference?



## gychang

I was supposed to get metal resistors rather than the carbon, to dampen the input sensitivity on the amplifier.

 what is the difference?

 thanks,

 gychag


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## LawnGnome

Quote:


  Originally Posted by *gychang* /img/forum/go_quote.gif 
_I was supposed to get metal resistors rather than the carbon, to dampen the input sensitivity on the amplifier.

 what is the difference?

 thanks,

 gychag_

 


 Carbon is a noisier resistor. But some people claim to like carbon resistors better because the noise makes things sound warmer.


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## Cauhtemoc

Carbon film resistors are often noisier than metal film resistors, although there are some exceptions. Riken and Kiwame make carbon film resistors that are as quiet as the very best metal film types. There are also carbon composition resistors, which are considerably noisier than film resistors.


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## tomb

One important difference between carbon and metal film resistors is _drift_. Carbons change value with heat and age. It's not something you want in most semiconductor circuits and not even in the CCS section of a tube amp (which maybe a semi-conductor circuit in many instances). Most likely, it's not something you want when setting the input impedance to an amp, either.

 However, carbons are usually preferred if a resistor is needed between the output of an amp and your load (headphones) - because they often sound better directly in the signal path.

 Amb even uses carbon resistors in the output of the Mini3 - a decidedly semi-conductor-based amp.


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## Zigis

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_However, carbons are usually preferred if a resistor is needed between the output of an amp and your source - because they often sound better directly in the signal path.
_

 

In steped attenuator what kinda of resistors are beter ?


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## tomb

Quote:


  Originally Posted by *Zigis* /img/forum/go_quote.gif 
_In steped attenuator what kinda of resistors are beter ?_

 

Oops - that was a typo. 
	

	
	
		
		

		
			





 I meant to say between the amp and your load, or headphones. Typically, high quality metal films are used in a stepped attenuator.


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## amb

Quote:


  Originally Posted by *tomb* /img/forum/go_quote.gif 
_Amb even uses carbon resistors in the output of the Mini3 - a decidedly semi-conductor-based amp._

 

LOL, I specify carbon film there not for its "sound", it's because metal film resistors less than 10 ohms in that size are very hard to find. At any rate, with such a low resistance, and the location of the circuit, it makes little difference between metal or carbon film.


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## BrianDonegan

Quote:


 Carbons change value with heat and age. 
 

They are also sensitive to moisture absorption. Again, drift, from which they never return.

  Quote:


 Kiwame make carbon film resistors that are as quiet as the very best metal film types. 
 

I have read this many times, including on the manufacturer's web site. Unfortunately, I have never seen any specs that would confirm this, not even on the manufacturer's web site, which I find odd. I have not heard them however.


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## tomb

Quote:


  Originally Posted by *Amb* 
_LOL, I specify carbon film there not for its "sound", it's because metal film resistors less than 10 ohms in that size are very hard to find. At any rate, with such a low resistance, and the location of the circuit, it makes little difference between metal or carbon film._

 

LOL - there I go assuming you did it because of _sound_. When there's a resistor in the direct output between amp and load, and it's carbon, I _assumed_ that's because of the tonal quality.
	

	
	
		
		

		
		
	


	




 Thanks for the explanation, though. 

  Quote:


  Originally Posted by *BrianDonegan* /img/forum/go_quote.gif 
_<snip>
  Quote:


 Kiwame make carbon film resistors that are as quiet as the very best metal film types. 
 

I have read this many times, including on the manufacturer's web site. Unfortunately, I have never seen any specs that would confirm this, not even on the manufacturer's web site, which I find odd. I have not heard them however._

 

Agreed - IMHO, Kiwames are "boutique" and have the qualities of same - _good tonal qualities which may or may not be because they're quiet (more often because they roll off the highs) and a corresponding lack of specific performance data._ Regardless, like a boutique capacitor - there are places where one is appropriate.


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## aych

i think it really depends on your preference. if you like a warmer sound and you dont plan on using your amp for a long time, i'd go carbon ^_^ i like that sound too


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## shrestha

hi...can anyone help me?
  i am confused about whether carbon resistors are semi-conductors or conductors. Can anyone answer me?
  Thanks


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## fubar3

Quote: 





shrestha said:


> hi...can anyone help me?
> i am confused about whether carbon resistors are semi-conductors or conductors. Can anyone answer me?
> Thanks


 

 A resistor impedes current flow and is indifferent to polarity.  A semiconductor blocks flow in one direction, but not the other.
   
  An engineer may choose a certain resistor type based on analysis, measurement, and cost. However, if you DIY something like a headphone amp, go with whatever provides satisfactory results.


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## splaz

Quote: 





fubar3 said:


> A resistor impedes current flow...


 
   
  When I first started out in electronics in my mind I thought that with a resistor there is somehow some sort of blockage or restriction and that surely this would lead to a build up of heat, due to the electrical 'friction' and electrons trying to force their way through. Water analogies didn't help with this...
   
  Makes no sense I know, just how my mind can tend to think at times. 
	

	
	
		
		

		
		
	


	



   
  Maybe I'd prefer, an "allower" which allows a certain amount of current flow, or something.


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## samsquanch

Quote: 





splaz said:


> When I first started out in electronics in my mind I thought that with a resistor there is somehow some sort of blockage or restriction and that surely this would lead to a build up of heat, due to the electrical 'friction' and electrons trying to force their way through. Water analogies didn't help with this...


 
   
  Resistors do heat up under high current (high being relative to the rating of the resistor).  If you put a 1/4 watt 15k resistor in a 120vac outlet, you'll push it to 1 watt, it'll get plenty warm, and probably smoke then catch on fire.  DISCLAIMER:  Don't jam a resistor into your wall outlet, you'll probably shock yourself if you're not careful.
   
  This is why higher watt resistors are ceramic, in a TO-220 package so you can mount it to a heatsink, or other designs to keep the the resistor under it's smoke point.
   
  Remember, energy is neither created nor removed, it changes form, in this case from electric to thermal.


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## Telstar

Quote: 





> Originally Posted by *Zigis* /img/forum/go_quote.gif
> In steped attenuator what kinda of resistors are beter ?


 
  Vishay z-foil naked. but they will cost u a fortune.


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## nikongod

Good gain structure (which is so hopelessly lost on most of head-fi) and Transformer/Autoformer volume control FTMFW.


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## J-Pak

Quote: 





nikongod said:


> Good gain structure (which is so hopelessly lost on most of head-fi) and Transformer/Autoformer volume control FTMFW.


 

 Big fan of these 
   
  But they can sometimes be expensive and large. Even in passive mode with a 2 vrms source and standard 26 dB gain power amp I would have liked finer control than the 2 dB steps on mine. 50 dB attenuation with 1 dB steps at the start of the switch get really expensive 
   
  But I only know of the usual places, Intact, Sowter, Tribute, Silk, etc. If there are cheaper options I am all ears.


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