Gut Punch Overdrive

[Ripthorn]

Hey guys, I have only been lurking for the most part for the last quite a while.  However, during my last pedal building kick, I discovered a combination of pre-existing boosters that actually created a great overdrive.  I am calling this the gut punch because if you want it to, it will really pummel your amp.  It's not terribly original, with only a few component changes, but what is pedal building if not some form of building on stuff that already exists?  This has a great range of sounds and can go from a nice light crunch to a pretty hefty OD. I suck at drawing schematics, so please excuse the quality of this one, but here we are:

[GibsonGM]

That one looks pretty cool, Brian!  Nice work, sort of has it all, doesn't it, LOL!   Even a Mosfet boost!

The schematic IS neat, not sucky...        Is the Flavor control pretty functional, does it make a big difference?

[Ripthorn]

The flavor control is very functional.  It's not like a normal tone control where you just dump high frequencies off to ground, it actually adjusts how much signal makes it in in the first place.  You can get super high trebly sounds or nice mellow, warm sounds out of it. All the controls are very functional, with plenty of everything (frequencies, crunch, and volume) on tap.

[duck_arse]

that 5088 transistor - looks like an emitter follower - but it's followed by a mosfet booster, w/ ~5M input impedance. have you tried connecting the mosfet direct to the filter section after the J201?

[Ripthorn]

I have not tried connecting it direct to the output after the filter section of the J201.  I will have to try that on the breadboard (once it is available after breadboarding my HP amp project).

[Ripthorn]

Alright, folks, I know this seems like a necro-bump, but I finally got some substantial time to play with this on my breadboard.  I took some suggestions into account and simplified it a good amount.  This sounds pretty good, I'll have to try to get some audio clips, but I want to box it up first so that it doesn't hum. I really like how it sounds. I did a really nasty perfboard layout in DIYLC that should make it small enough to fit a 1590B with boardmounted pots, but I want to try to squeeze it into a 1590G because I bought 10 of them from Mammoth for $1 each (they appear to be clearancing them). I'll keep you guys posted, but if someone works up a pretty layout, I would love to see it.

[marcelomd]

Hi,

I just took a quick look and I see that in the first stage you have +9V - crunch knob - 1k - transistor - etc. When the crunch knob is fully to the left, won't it mute the effect, putting +9V directly into the next stage? I image a better solution would be to swap the knob and the 1k collector resistor.

Just trying to help.

[Ripthorn]

That's a good question. I did not think to try that.  I still have this on the breadboard, so I can give it a shot. I put that there because I noticed that without it and with crunch all the way up, the effect was very gated and nasty, so I tried to simulate not letting the knob ever getting fully turned up.  Your way is likely better. I'll keep you posted.

[Ripthorn]

Had more time to tinker with this.  I tried the previous suggestion, and didn't notice any improvement or change.  I did end up making the 820R resistor off the emitter of Q1 a 2k7 and that helped.  I think I could resolve the remainder of the issue with a slightly different cap, but haven't tried that yet.  I did solder up a quick perfboard version. It's noisy just hanging outside on my bench, but I like how it sounds.  Here is a really quick and dirty video clip of the first pass on perfboard.  I have reworked the layout so that it isn't quite so ugly, but it's still not pretty, but at least has board mounted pots.  I plan to put this in a 1590G.  I'm pretty pleased, but I'll know more once I get it boxed up and crank it.  It really likes to go into a an amp that will break up, as it has tons of output and is beautiful stacked.  Putting a booster into it also takes it into crazy gain territory.  It's been fun, I may continue to tinker with it, but I'm pretty happy with it for now.

https://youtu.be/woaVgqGUloY

[marcelomd]

Nice tone!

[Ripthorn]

Thanks! I'm reworking my layout to try and make it prettier and such, but I kind of suck at layout design.  Still, I'm digging the sounds from it.  Just need to get the enclosure drilled and painted.