carbon composition resistors in fuzz pedals

[Blue Mark]

Many of the hi priced fuzz pedals use them. Does it really make a difference or is this just marketing hype?

[phillip]

Marketing hype.  They're actually fairly detrimental to the sound.  

The only reason that used them in the original versions of the pedals is because they're all they had to work with.  I'm sure that if they had these nice 1% metal film resistors back in the 60s, we'd be seeing a lot of vintage Fuzz Faces with them

Phillip

[cd]

http://www.geofex.com/Article_Folders/carbon_comp/carboncomp.htm

Note that the article above does not discount the fact that CCs sound different, but the difference requires a huge voltage swing (50-100V) and comes at the cost of noise, reliability, etc.  The difference, which is already miniscule in a tube amp with high voltages and large voltage swings, is a non-factor in a 9V powered effect.  So the answer is pure hype.  Modders need to justify charging you high $$$ for a 10-50 cent resistor, it's trendy, you feel good about having the original part (even if it makes no difference - i.e. old vs new JRC4558Ds), CCs cost ten times more than a regular resistor (even though we're talking 10 cents versus 1 cent) so you feel good about having the most expensive part in your FX, etc.  Sonically, it makes no difference.

[Mike Burgundy]

Sonically, it makes no difference

Except for the noise. They tend to hiss like hell - now that's nice and authentic, no?

[RedHouse]

I would agree with Mike, I've built identical boards with Metal Film and CC's, the CC's were noticeably noisier.

[Eric H]

Nice progression of useful info.

Just wanted to point out that the noise contribution of the lowly carbon-film resistor is only __slightly__ greater than metal-film.  You'll have a tough time hearing the difference in most stompboxes (with some possible exceptions I'm certain someone else will be happy to note

-Eric

[Mike Burgundy]

to a certain degree you're right, but try them in a high-current (well, relatively high - we're still talking 1/4W or 1/2W resistors, but *push* them) or before a JFET input as an input-to-ground resistor. This is usually high, and receptive. Sheesh, that's nasty.
They also tend to drift - or so I'm told. I've seen more CC and Cfilm resistors that had drifted (or plain failed) than metal film, that I know.

[Lonestarjohnny]

Mike, heat one up with a hairdryer with your DVM hooked to it and you'll see that they will drift on a hot day, beside's they get old quicker than Metal film do, and when I bust open an old  silver face Fender it's the first thing I do is jerk out all the old noisey carb comp and I like carb film in Fender's, just my own taste, maybe not for everybody.
JD

[Mike Burgundy]

there's the drifting for you.
Also a nice experiment to do the hairdryer thing to Ge transistors, too
Why am I hearing someone say "Can you make it sound *just* like it did the moment before it fried?"

[Ammscray]

Marketing hype.  They're actually fairly detrimental to the sound.  

The only reason that used them in the original versions of the pedals is because they're all they had to work with.  I'm sure that if they had these nice 1% metal film resistors back in the 60s, we'd be seeing a lot of vintage Fuzz Faces with them

Phillip

Hey Phillip!

I wouldn't say they're "detrimental" to the sound, all my vintage pedals sound great with them in there ...with no more noise than normal...true lots of them can be noisy but there's plenty that aren't too...I've built many FF's and RM's and such with both metal film and CC and not only is there no difference in sound but not much difference in noise either if you got good ones...

this is mostly because there's so few of them in most vintage pedals to make any difference...

 in a vintage Fender amp that's a different story altogether, normally I only change the plate-load 100K resistors if they're really noisy with but in my experiences with changing out all the CC's for CF or MF in old amps, the tone definitely changed to my ears...not for the better...and also I was replacing them with the values that they had drifted UP to...which is usually what happens...

 They didn't have metal film in the mid-60's to my knowledge, but they definitely had 5 percent CF...most original Vox wahs, most Colorsound pedals, and lots of others used 1/2 watt CF in there...

to me there's more of a difference in using CF and MF in large quantities...a guy I knew once took on the painstaking chore of changing ALL the CC's in his old Scott tube reciever for all MF's...he used precision values to match the drift...I heard it with my own ears, the amp sounded brighter and sterile and way different after the fact...there's TONS of them in there, you have to see it to believe it...and, it turns out the "noise" was coming from a bad tube...

no, it wasn't me, I like to tweak but that was something I would never take on

[Mike Burgundy]

tube amp: high voltage, large voltage swing. That would hold with the GEO article - where the point is made that all detectable differences occur with high voltage/large swing. Good stuff, really.