Replacing Transistors

[supernaut]

I want to build a simple treble booster. This one particularly: http://www.geocities.com/j4_student/voxtreb.jpg Just because it uses silicon a transistor rather than hard to find germanium ones. However Is it possible to replace that transistor with other ones for different sounds etc? And how do I know which ones it is okay to use as a replacement?

[Scruffie]

Most NPN transistors would work, the best thing to do is use a socket (A DIP 6 Pin Socket cut in half or a transistor socket) and swap out a couple of transistors to see what sounds best to you, hFe will be a thing to look out for on data sheets to see how much gain they will provide. Check out the Electro harmonix LPB-1 http://www.montagar.com/~patj/ehbsters.gif it's basically the same but there will be alot of info on the net about it (check out dano's beavis audio site) changing the input and output cap to a lower value will create a treble booster the screaming bird/tree to be precise.

[supernaut]

Okay, thanks for that. I have a Hfe function on my multimeter as well. So if I use transistors that dont match in terms of gain would that damage any components or cause the effect to not work?

[petemoore]

  Notice how the little arrow in the circle where transistors are drawn changes direction.
  NPN has it facing toward the outside, PNP toward the inside.
  You want NPN for this negative ground circuit.
  For some reason they decided to show the PNP in the diagram 'upside down', but the arrow points 'in'.
http://en.wikipedia.org/wiki/Bipolar_junction_transistor
  Thats the only thing to 'match' as far as damages to the transistor, note the polarization mark does matter for electrolytic longevity, reverse polarization may damage the polarized capacitor.
 

[supernaut]

Okay thanks for the help. I'll definitely be picking up a few 2N3904's tomorrow but will keep that in mind.