Ins and Outs of matching components

[das234]

Thanks again to the forum for all your help with my beginner questions.  Here's another one.  I read here and there about the need to "match" components (mainly transistors I think) but I haven't been able to fill in the blanks so it makes sense to me.  Just what components should I be "matching" and how do I go about it? 

Dave

[midwayfair]

"Matched sets" of transistors for fuzzes are basically just two transistors that fall into a particular gain range and are likely to bias correctly with common values.

Matched FETs for phasers and similar pedals are necessary because you need to ensure that they will have similar performance when modulating each frequency band/phase. The other time FETs are matched is when they're in pairs, like in the Wampler amp-in-a-box circuits.

Matching capacitors, pots (like on a dual ganged pot), or resistors, is rarer, but any time you have two things that have to do the same thing, the design will usually call for it. Actually measuring them to be matched, however, is extremely rare.

[das234]

Ok that helps.  So, if I'm going to build myself a phaser (a small stone is on my wish list) how do I know what  needs to be matched from looking at the build docs?  And once I know what to match, how do I match them?

Thanks again for your help and patience.

[Haberdasher]

nothing would have to be matched on a small stone since it is an OTA phaser.  the ross phaser is also similar to that one and may be easier to get parts for since it uses ota chips that are still in production.  but all those transistors you see listed for the sm stone are just silicon bipolar's and there's no point in matching those.

now if you built a phase45 or phase 90 you would need to match the jfet transistors.  different type altogether.

[danwelsh]

I was wondering the whys of this question too....thx man