Transistor Question

[esurreal]

I built the hott fuzz pro but could never get it loud enough with the jfet transistor in it. I pulled the jfet because it's much louder without it. Today I put in a tin can 2n2222a and the volume is huge. When I use a non-tincan 2n2222a it drops in volume. I also tried a tincan bc109 and the volume once again boomed. Seems that only the tin-can transistors have the volume boost.

My questions are will this hurt my circuit? Can it fry it or anything like that? And why do you think the tincan silicon transitors are so much louder. Thanks

E

[esurreal]

I'm going to re-word my question. The schematic says to use a jfet (j201), but i am using a bjt (2n2222) instead. Is this ok? It makes it much louder. I don't want to destroy my circuit. thanks.

[demonstar]

I'm haven't seen the circuit and I'm not promising but most likely the most damage you could do is destroy your transistors. I'm pretty sure the silicon BJTs are much louder beacuse I'm sure I've heard generally they have a higher voltage gain than FETs.

Beware though what you are doing is like saying here's a machine that's meant to run on heaxnol as a fuel and you are giving it butanol. It's not what the designer specified so it's always going to be sketchy territory. Normaly FETs and BJTs can't be swapped for each other however, in this circumstance it appears that you've got away with it. You should be alright I think.

[slacker]

You mean this http://www.diystompboxes.com/pedals/hfuzz1.jpg?

The jfet is just used as a buffer, although I don't understand what the resistors from the source back to the gate are doing.
Putting a BJT in there should work fine and it certainly won't damage anything. The only thing is that the pinouts for the BJT and jfet will be different so if just dropping a bjt in without twisting the legs around works that probably explains why the J201 doesn't.

[demonstar]

Ian, does that mean that a BJT can be subbed in instead of a JFET when it is used as a buffer or is it just O.K. in this scenario? I always thought the bias would be different.

[esurreal]

ok. One thing is I don't have a j201 so i tried a j202 instead. I also tried a mpf102 with even worse results. It seems that when i pull the buffer jfet out, the pedal sounds the same and is louder than with the buffer in. strange. With the BJT the volume is really loud, but the tonal qualities are a little honkier. If  I add a capacitor to the gate and add a resistor to the drain would this make it more biased for a BJT.

[col]

If you are managing with a 2N2222a and you need the same pinout try a 2N7000 or a BS170 as I think they have a compatible pinout as CBE to DGS, you'll just have to make sure you put it in the right way round as I can't remember off the top of my head which way around they go.

[esurreal]

thanks a lot i'll try those. Do you know which legs of the 2n2222 i would need to switch around to make it the same pinout as a jfet?

[esurreal]

Wow, I learn something new everytime I come on here. I just realized that I had the pinouts wrong on the jfet. You gotta twist the source pin to the outside and the gate pin to the middle. Thats what my problem was the whole time. You guys knew it too. You made me learn it the hard way.haha. Or maybe you didnt realize i'm such a noob. Anyways, the pedal sounds fantastic now with the j202. Thick,loud, luscious fuzz. Thanks for all the help.