Members Noise... Posted February 8, 2008 Members Share Posted February 8, 2008 I'm ordering parts to build a few different boost pedals, and it calls for any NPN transistor. I'm going to socket all of boards so that I can change the transistors around, and I'm ordering a bunch of normal silicon transistors to find what I like best. I also can order a Germanium transistor to try as well, but they're quite a bit more than the silicon transistors and I want to be sure it will at least sound decent. The germanium transistor I'm looking at is a AC187, and it would be going into the DIYStompboxes beginner NPN boost project. Will it sound good, or would I be throwing away $5 getting the Germanium transistor? Link to comment Share on other sites More sharing options...
Members Noise... Posted February 8, 2008 Author Members Share Posted February 8, 2008 Anyone? Link to comment Share on other sites More sharing options...
Members TheGareth Posted February 8, 2008 Members Share Posted February 8, 2008 I'm not sure myself but I think for an extra $5 you couldn't go wrong. Link to comment Share on other sites More sharing options...
Members danceatron Posted February 8, 2008 Members Share Posted February 8, 2008 Usually treble boosters use a single Germanium. I think for $5 you might as well give it a try. Link to comment Share on other sites More sharing options...
Members mlabbee Posted February 8, 2008 Members Share Posted February 8, 2008 I've only compared them in treble boosters and fuzzes - never a clean boost, so take my view with a grain of salt . . . germanium is warmer, less of an edge to the sound - silicon definitely can get ice-picky. I was a little surprised by how much difference there was in the circuits I tried (I've become something of a "tone" skeptic after dong some A/B tests on the "magical" 4338 chip in a tubescreamer). Definitely not a subtle difference, so I think it's worth the $5 to make the comparison. Although you should make sure the circuits are truly interchangeable. From what I recall, germanium transistors require a bit more care and feeding to bias them correctly. Link to comment Share on other sites More sharing options...
Members Noise... Posted February 8, 2008 Author Members Share Posted February 8, 2008 Ah... Does anyone know if the AC187 will actually even work in the DIYStompboxes beginner project? I know it's just a simple NPN boost, but I don't know if there are any requirements for the transistor other than that it has to be NPN. Link to comment Share on other sites More sharing options...
Members TheGareth Posted February 8, 2008 Members Share Posted February 8, 2008 I've always wondered what NPN stands for.... Link to comment Share on other sites More sharing options...
Members mlabbee Posted February 8, 2008 Members Share Posted February 8, 2008 I have no idea - you should ask in the DIYS forum. Back when I was building stuff, I asked all sorts of questions there and got a ton of great answers/information everytime - very cool people there. (Not that people here aren't cool - just more likely someone over there will have tried it and can tell you for sure whether it will work). Link to comment Share on other sites More sharing options...
Members mlabbee Posted February 8, 2008 Members Share Posted February 8, 2008 I've always wondered what NPN stands for.... NPN refers to the kind of gate in the transistor - N is one kind of material, P is another. You can have an NPN or a PNP - the letters in the middle refers to the polarity of the gate material. (N = negative, P = positive, meaning how they are doped to be postively or negatively biased . . . something like that). It governs how you hook them up to power. Link to comment Share on other sites More sharing options...
Members Liberty Belle Posted February 8, 2008 Members Share Posted February 8, 2008 you could build the cream pie Ge boost,it uses an NPN AC127 (available on ebay)i have the schem if ya dont already. Link to comment Share on other sites More sharing options...
Members andrew_k Posted February 9, 2008 Members Share Posted February 9, 2008 If you're referring to the diystompboxes beginner project, you'll most probably have biasing problems if replacing the Si transistor with a Ge one. On the schematic there's a 10k resistor connected to the transistor's collector -- this is for biasing. Replacing that with a 20k or 50k trimpot and you should be fine. Play through the effect and turn the trim pot until it sounds right. (or use a mulimeter to bias to 4.5v at the collector and adjust from there) Link to comment Share on other sites More sharing options...
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