Carbon Film vs Metal Film

[ichilton]

How much difference in sound does using carbon film 5% resistors make over metal film 1%?

Is any sound difference just because of the component variance, or is there a different sound in the material?

Thanks,

Ian

[IvIark]

If you had a metal film and carbon film resistor and they both measure exactly the same resistance then I very much doubt you would notice any audible difference between them at all.  When people talk about different sounds of resistors in stomp boxes I'm pretty sure they're experiencing compounded tolerance differences between the two types.  

But there is a caveat for that with me.  Because of tolerances it means that carbon film or carbon comp CAN sound different to a build with metal film resistors, but not due to their composition.  Who is to say that a bang on 100K or 47K (for instance) resistor will make a circuit sound best?  Those values are only used in the first place because they're a recognised standard E6 value, but it could often be the case that carbon comp resistor that has drifted 15% over the years sounds better simple because it biases a transistor better, or hits a sweet spot in a filter.

So if you're a tweaker and like to swap and change components to fine tune it, then it may well be worth getting as many types of resistors as you can (or a complete set of E192 metal film series so you have all the in between values too).  If tweaking doesn't bother you so much, then get 3000 metal film resistors for £10 from China and don't worry about it.

[ichilton]

That's what I was thinking - thanks.

Ian

[Heath]

Definitely seconding what Mark said.  

I'm still a neophyte at this stuff, but my thinking is that I can get a crap-load of 5% carbon resistors for next to nothing.  I *LIKE* knowing I have any resistors I need at any given time without having to make a new order for 3 150k resistors (for example) which invariably leads to me buying a bunch of other stuff to justify the shipping.

On the other hand, I really like having those pretty blue resistors that I know are going to be spot on, especially if it's a build that is expensive/really complex/important.. but I'm not going to pay $0.20 each for them.  As Mark suggested, I keep an eye out for lots of them from China or wherever when they're cheap.

That way, out of 30 resistors for a build, if I can manage 25 of them with the 1% metal resistors, and fill in the other 5 with the 5% resistors, I feel pretty good about my overall tolerances without having to know every tiny little detail.  Chances are, using nothing but 5% carbon resistors will work fine, but with my tendency towards jacking up even simple builds (yes, I managed to build a non-working CB Naga Viper... fear me...), it's one less thing against me.


One other thing... even though it seems harder for me to differentiate the color bands on the 1% blue resistors, the lighter colored 5% resistors, while easier to read in a perfect world, are often very poorly marked.  I have some where the Yellow bands did not print at all, so I had to figure out that a missing color band = Yellow.

Take this all with a grain of salt from someone who is still figuring this stuff out.  Just thought a viewpoint from the "still learning" might be worth the input.

[ichilton]

Cool, thanks.

I've placed some orders with Tayda for stuff to build a load of pedals and both 1% and 5% are about $0.01 minus a $15 discount code so i've ordered a decent quantity of each. Between all of the pedals I ordered for, I must have covered most of the popular values!

Ian