NSFW Boost (work safe thread)

[ashcat_lt]

I finally got around to building my booster pedal!  I've had most of the parts laying around for over a year, but...you know...excuses...

Here's the schematic:

A pretty simple little opamp booster, with a few added features:

1)  Sw2 "Wail" adds 500K to the feedback path, so that the gain knob then starts at 10 and goes to 20!

2)  Sw3 "Scream" drops a couple of back-to-back diodes across the feedback loop for "soft clipping" ala the TubeScreamer type OD pedals.

3)  Sw4 "Squeal" cuts out a bunch of bass, making it into more of a treble booster.  Severity is dependent on the gain setting.

5)  I used a TL080, and the 180pF compensation cap is the same that I used in my Rat clone.  It's supposed to slow the slew rate down to somewhere close to the original Rats.  Can't say for sure what it does to the sound here.  The opamp is socketed.  Maybe someday I'll drop in an 071 and see if I can hear a difference.  I expect it's something very subtle, and only really has an impact at the highest gain levels.

6)  R7 and R9 are trimpots, used to set the minimum gain.  I can't see any reason to have the gain knob go all the way down to unity, since that's what the bypass switch does.  Set as shown (80K and 47K respectively), it's a noticeable but not huge jump.  I may tweak this so I can use the minimum is my "default" boost level.  R7 also impacts the bass cut action.

Here's the gutshot:

Yes, that's without the opamp installed.  No, you can't see the solder side nor the offboard wiring.

This is the first pedal I've done with anything resembling real graphics.  Laser printed onto a sort of vinyl sticker stock.  Eventually I might spray it with some clear coat, but I may have to re-print the sticker first.  It is mildly NSFW, so here's a link.

I haven't really done much with it yet except to plug it in to make sure everything works as expected.  It sounds pretty darn good through my Vox AC4.  The OD setting of the "Scream" switch is pretty cool.  Not super distorted, just a bit edgy, with some interesting clarity that leaks through in a way that's pretty different from what my Rat does.  I guess you could call it "transparent" or something.  It doesn't sound much like the TS, though, until you flip the "Squeal" switch.  Also, with the trimpots set where they are now the total gain doesn't get quite to where a TS would.  All in all I'm pretty happy with it.  I finally will have boobies on my pedalboard, and I can give my brother his Boss TurboFuzz back!