Transistors

[marcdemersKNG]

Hello everybody, I'm just getting into building pedals, I've been building guitars for years, but now I want to branch into something new, could anyone please fill me in on how the values of transistors affect the the amount of fuzz or gain? My first project is a fuzz box. And I want to design it from scratch, give myself a real challenge and so if there is any good pages on the theory of designing circuits and what not it'd be greatly appreciated! 

Thanks, Marc

[Pyr0]

Welcome.
read this,

http://www.geofex.com/Article_Folders/fuzzface/fffram.htm

in fact read everything on that site

[Kesh]

I'm also figuring out how transistors work at the moment. A great tutorial for how clean, 1 transistor amplifiers work is at http://www.st-andrews.ac.uk/~jcgl/Scots_Guide/experiment/lab/expt5/page1.html

One main point is that the main effects are determined not by the transistors, but the components (mainly resistors) around them. Transistor values more set upper limits on what you can do.

Some circuits though (like the fuzz face) are more transistor-centric, and values like hfe matter.

[marcdemersKNG]

Thanks guys, I live in ontario, any idea where I can get a DMM? I'd much prefer to not have to order one

[nightendday]

Thanks guys, I live in ontario, any idea where I can get a DMM? I'd much prefer to not have to order one

princess auto has a bunch of them, I got one for 4.99$ that had HFE reading on it.

I'm in st catharines ontario

[marcdemersKNG]

Well thanks, my fellow Ontarian

[LucifersTrip]

Hello everybody, I'm just getting into building pedals, I've been building guitars for years, but now I want to branch into something new, could anyone please fill me in on how the values of transistors affect the the amount of fuzz or gain?

after building a load of fuzzes, you will realize that it is the other components (caps, resistors) that have more effect than the values of the transistors

ie, you can give me a super high gain transistor and I can make it into a clean boost and I can make low gain transistors into fuzzes...and vice versa

[marcdemersKNG]

So really its all about experimentation? I don't have a broad knowledge of electronics, do I have to have a set value that the signal comes out as or what? thanks guys

[LucifersTrip]

So really its all about experimentation?

DIY    ....yes, that's the fun for many...others just buy PCB's and paint-by-numbers

I don't have a broad knowledge of electronics, do I have to have a set value that the signal comes out as or what? thanks guys

not sure what you're asking...

[marcdemersKNG]

I mean like the pedal is run off of 9volts so obviously I have to use the appropriate components to maintain that, but what about capacitor values and resistor values, are those really all free game for experimentation or do I have to do some sort of calculations to place the right values in the right ares. I know that its crucial for LEDs but what other components must have a proper valued resistor in front of them? also how do I calculate what size pots I should use? I build electric guitars so I know how to wire pots but I usually only ever had to worry about 500k and 250k pots.  Thanks guys.

[GGBB]

Thanks guys, I live in ontario, any idea where I can get a DMM? I'd much prefer to not have to order one

CT.  If you're not in a big rush, these have been known to go on sale for as low as $10.  And these for $20.  I have both and they are quite decent.  Sayal also has a bunch.

[amptramp]

One of the meters I use most frequently was from Canadian Tire.  Princess Auto is the Canadian equivalent of Harbor Freight in the US and they have some good deals.  One piece of advice: a lot of meters top out at a 2 megohm resistance measurement.  This is not enough for some pedals that use tubes or LFO's.  Better meters go to 20 or 30 megohms.

[Kesh]

also, some meter's voltage measurements has 1Mohm impedance, meaning it might affect high resistance circuits, like biasing networks, so not give an accurate reading. 10Mohm is better and still available in the cheaper DMMs