Fallstaff OD [non-Madbean content] (this is something ... sort of new)

[midwayfair]

EDIT 1/28/13 to include the PCB build document.

I made this.

This might be a nice change for people who like Rangemasters but just can't get them to work in their chain.

(I posted this on DIYStompboxes, too. I hope it's okay to put the same build report on two forums.)

Background:
I started building Rangemasters in February, just after I started build effects pedals. I love the sound of most old germanium effects, but I use a compressor as my "base" tone, and an orange squeezer is pretty much always on in my rig. This makes a treble boost just a unity volume sparky thing for my setup, because they'll amplify the high end content of the Orange Squeezer into the stratosphere. It can get pretty harsh in a stock setting above unity volume and also the volume knob seemed to behave differently - percieved unity volume when the compressor was on was much lower on the dial than when the compressor was off.

I started digging around for ways to balance the sound. The easiest was to use one of the input cap mods or add an input cap tone knob (which I did - and I like the pedal that came out of that just fine). But I thought it would be much more interesting to work up something that sounded the same whether a buffer or other pedal was on in front of the circuit or not.

Adding a buffer ...
After fiddling around with tons of input/output camp values and adding a few different small capacitors across the volume knob, I remembered that one of the great things about Skreddy's Lunar Module and Screwdriver is that they took an effect (the Fuzz Face) that normally hates having pedals in front of and made it sound good by adding an extra input stage.

So I went back to the breadboard and built AMZ's simple buffer. Harsh city with a treble booster. But I tweaked some values, removed the redundant circuitry (no need for an output cap in the buffer section, for instance), and added a treble cut. A little more tweaking and the boost soon behaved the same when it was just guitar > boost > amp as when it was guitar > comp > boost > amp.

My "color" knob circuit
There was one last thing. While tweaking every possible value and component I could in this circuit, I discovered that adding a diode clipping section could add bass content. I finally settled on a germanium diode and 1N914, both facing toward ground, which added the most bass. [Edit: thanks to my friend Keefx for giving me the benefit of his ears and telling me that the 1N270 Ge diode sounded better than the 1N34A.] Originally I planned on making it a switch that also added a cap from the volume knob to ground to cut the highs and make this a bass booster, but I found that I could get a lot more interesting sounds by putting it on a pot. I've made some notes in the PDF about tweaking the values of this circuit.

I can't think of another pedal that uses a tone control quite like this. It adds some distortion and bass from the diodes, but it also cuts the highs at the same time and so the distortion evens out some. That's why I'm calling it a "color" knob - it's more than just a tone stack.

Here's what I ended up with:
[EDIT new schematic, drawn in Eagle 1/27/13.]


Here's what it sounds like with lots of notes:
[Edit: this is the current version.]

Prototype version: http://www.youtube.com/watch?v=GbZq26F5ZWg

And here's the build document:
https://docs.google.com/document/d/1033QEzKtTQJ0B3pTqJyp3mo-y4V7ErbM35hi3phTJLI/edit

This is not exactly a treble booster as I built it, although it sounds similar. I chose values that provided a more of a full range boost; you could use smaller input caps and it'll function more like a classic Rangemaster.

The color knob can be added to any existing Rangemaster, by the way, but I wouldn't suggest adding the buffer input stage if you're using a normal-sized input cap. It'll be much brighter.

I've got some good pics but I forgot to pull them off the camera. Doh! I'll post them in the thread after I get home.

[KeefX]

What's up with the blues at the end?

[midwayfair]

What's up with the blues at the end?

Kindly direct all smarmy comments about my playing to the vid itself, K.

And welcome to the forum.

[jkokura]

That's a pretty cool thing dood. The fact that you largely did all this work on it yourself is especially cool.

Jacob

[midwayfair]

Now with pictures! Thanks for the compliment, Jacob.