Transistor Matching - Does It Always Need To Be Done?

[jojofogarty01]

When I buy transistors off of TAYDA I usually just get the exact number of the type I need and socket them into the pcbs. For instance, if one of my builds calls for two B549C transistors, can I just buy two and plop them in, or do I need to order a few and test and match them?

 

[rmfx]

Depends on the circuit. A lot of things you can just pick n plop, but there are some circuits where you need to be a little pickier. Phasers will need matched JFETs. Lots of lower gain fuzz pedals require each transistors to be in certain gain ranges to sound "best". In a Ross compressor, you should use a pair of closely matched transistors in a certain part of the circuit.

What pedal are you referring to?

 

[BuddytheReow]

I always get a few extra. They are pretty cheap you'll kick yourself if one is defective and have no spares. Plus, it's always good to have for your next build or if you want to switch them out in a different circuit to see how it sounds. Tinkering is one of the fun parts . You never know what you might stumble upon.

Also, sockets will work wonders here.

 

[Chuck D. Bones]

The vast majority of the time "matching" is not necessary. In the few circuits that do require matching, one has to ask which parameters need to be matched and how closely? Sometimes, as in the case of Germanium Fuzz Face circuits, the term "matching" is used rather loosely. The two transistors are not matched to each other. They, and their biasing resistors, are matched to the circuit's biasing requirements.

Standby for an article on matching in Chucks Boneyard.