madbeanpedals::forum

Projects => How Do I? Beginner's Paradise. => Topic started by: beneharris on June 13, 2016, 08:50:17 PM

Title: Carbon comp tolerance
Post by: beneharris on June 13, 2016, 08:50:17 PM
I bought a huge bag of carbon comp resistors off of ebay. Some of them read dead on with my multimeter, but some of them, which are 5% are reading double, to triple that. The worst offenders are a stack of 6.8ohm that read anywhere from 7.4-7.9. I'm thinking they're just really poor quality, but even so, that surprises me. Is this just carbon comp? I'm not super worried about using them, just surprised at the difference between the seemingly same value resistors.
Title: Re: Carbon comp tolerance
Post by: EBRAddict on June 13, 2016, 10:39:06 PM
Either your multimeter is malfunctioning or those are crap parts.

Title: Re: Carbon comp tolerance
Post by: beneharris on June 14, 2016, 12:30:30 AM
I'm going to go with crap parts. I used 2 different ones. That's okay, I didn't pay much for them.
Title: Re: Carbon comp tolerance
Post by: lincolnic on June 15, 2016, 05:00:18 AM
You might want to try replacing the battery in your meter anyway to see if that changes anything. They behave really strangely with low batteries.
Title: Re: Carbon comp tolerance
Post by: alanp on June 15, 2016, 07:20:44 AM
Carbon comps are not known for accuracy as a whole.

It's part of why back in the day, you'd sometimes get that one amp with ungodly mojo, or that perfect fuzz that sounded like nothing else. All the bad tolerances threw the values out of spec, and the planets aligned, and the collective bad tolerances added up to something beyond what the production spec was, and you got lucky that it sounded good.
Title: Re: Carbon comp tolerance
Post by: beneharris on June 21, 2016, 02:50:17 PM
Quote from: alanp on June 15, 2016, 07:20:44 AM
Carbon comps are not known for accuracy as a whole.

It's part of why back in the day, you'd sometimes get that one amp with ungodly mojo, or that perfect fuzz that sounded like nothing else. All the bad tolerances threw the values out of spec, and the planets aligned, and the collective bad tolerances added up to something beyond what the production spec was, and you got lucky that it sounded good.

See, I thought that, too. But this just seemed so far out of line that I kind of threw that theory out the door. Maybe I'll breadboard a fuzz and see how it takes with them.