Woo! The problem with my Sparkleboost was a bad transistor!

[RjM]

After weeks of debugging..... I now have a working Sparkleboost. I guess I fried the transistor when I soldered it in! I got an IC socket, made it into a tranny socket, put in the new tranny, and wham-bam-thank you ma'am-IT WORKS! Now I'm going to use another IC socket for the clipping diodes I'm adding in! Oh man.... I feel really happy, but really frustrated and kind of stupid right now. At least the dang ol' thing works now. Also, adding a 3K9 resistor off of the ground lugs of the Gain pot does a great job of evening out the taper! So, this is how it feels to finally have something working....

[Dragonfly]

After weeks of debugging..... I now have a working Sparkleboost. I guess I fried the transistor when I soldered it in! I got an IC socket, made it into a tranny socket, put in the new tranny, and wham-bam-thank you ma'am-IT WORKS! Now I'm going to use another IC socket for the clipping diodes I'm adding in! Oh man.... I feel really happy, but really frustrated and kind of stupid right now. At least the dang ol' thing works now. Also, adding a 3K9 resistor off of the ground lugs of the Gain pot does a great job of evening out the taper! So, this is how it feels to finally have something working....

im glad you got it going...that happens sometimes....

i thought you might like that resistor trick  :wink:

[petemoore]

I started socketting them, and almost always do, it's very hard to determine which of one or two things is wrong.
 I have Q's in the 'abused bin'...ones that have been exposed to misorientation or wiring problems whatever, most of them seem to work well...except a few of the GE's, which do not work.

[GreenEye]

Congrats!  I've had to rebuild entire circuits 2 or 3 times to debug them, and even then it's still satisfying when it works in the end....

[RjM]

It sounds pretty great.... But.... there is one small problem. When I try to put it before other effects (My MT-2 and EQ pedals) no sound comes out. I'm thinking it is a ground problem, but I don't know how to fix it! Any of you ever have this problem?

[RjM]

I'm thinking there is still a small problem somewhere, or rather a big problem, since there is some background hum, and when I turn the volume knob down, the hum increases, and then there is no sound with the volume knob at 0. I can hear some guitar signal through the middle to last part of the taper where it hums a lot. It does boost the clean signal quite a bit, and the gain knob definately adds some subtle grit. Turning the gain knob down now doesn't effect the volume, so the new tranny has fixed some things. I'm not quite sure what is wrong. Also, how much distortion should I expect from the clipping diodes? I put two silicons in series, and on the other side, I put a germanium and a silicon, and there really isn't any change in sound, so I think there is still something wrong, but the main problem was that bad tranny, but still... with that many diodes, I should be getting quite a bit of distortion, or I would think so anyways.

What do you guys think? I'm closer than ever to having this thing completely working. I made an audio probe, where should I poke around with that? What should I measure with the DMM to find the problem? Is it that maybe the MPF102 is a lower-gain FET, and that is why I'm not getting distortion from the diodes? I need to order some NTE458s...