FYA Garagemaster

This day had to come.

Recently i was asked if i could build a vintage sounding treble booster for modern pedal board. Sure. Why not. And quick looking around showed that there were not that many (!?) rangemaster modernizations around. Or yes there are, but most of them do have something wrong with them - missing vital controls, still using PNP transistors and/or positive ground, sounding too thin or trying to be something completely different, not a treble booster, etc. So i took out the classic Rangemaster schematic and had my way with it. Basics are still there, only with an NPN transistor, large power supply filter cap and a series polarity protection. The switchable input cap is probably the oldest trick in the book, but i tried to voice it so that the frequency response stays at treble boosting area, while still being usable all the way. After all, we're trying to make the best possible treble booster for a modern setup. So to go forward, we got our input pulldown to keep switching POPs to minimum, followed by the "EQ switch" that has a standard 4n7 input cap in circuit all the time, upped by another cap at 2n7 for a fuller frequency response. Transistor also gets its forward bias voltage as the original Rangemaster does, from 470K resistor from supply and 56K resistor to ground. This equals in around 0,958 volts if the supply is at dead 9 volts. Gain is applied by setting the output from between the collector and supply via 10K linear pot. At zero, the output is killed by supply voltage, at maximum the boost amount is enough, or at least enough. This is followed by an output cap (to keep the DC away from the output) that has a slightly bigger value than the original and a another pulldown. Now, what's different in my take on the classic is the "bias" pot. The original Rangemaster would have 3K9 resistor from transistor emitter to ground in parallel with a bypass cap of 47µ value. After a short breadboard session, i settled for 2K7 and a 50K pot in series with it. At maximum, the gain is slightly more than it would be in verbatim Rangemaster clone - and staying clean and soft like a true Rangemaster would. But here's the thing, once we put the 50K+2K7 in parallel with the 47µ, we'll get the misbiased germanium tones ála Hornby Skewes Shatterbox, EHX GeOD and/or Germanium4 Big Muff Pi. If you are familiar with either, you'll know what i'm talking about - that mushroom cloud tone that is both super ugly and yet still pretty cool. The one that makes everythign sound truly broken. In my take of the Rangemaster, i've incorporated a control to set that amount of total destruction to the the classic. This should take you further than a Shatterbox, EHX GeOD and anything else. If not by itself, you should try to boost another pedals with it.

Just finished building a three piece set of these. One for the guy who was asking, one for me and one's for sale. And here's the "factory layout". I hope you are happy with it without a schematic - i just told you what the differences between this and the original Dallas Rangemaster are, so you really shouldn't need one.

The transistor model, gain and leak range- that's one thing i'm keeping a secret. You should be happy with anything - maybe even a 2N3904 could work, if you care to tweak the value of the 2K7.

Oh. The name? The tone of this circuit reminds me a lot of the guitar sounds of the 60s garage bands, such as The Iguanas, The Vistas and so on. Use this circuit to make your modern amplifier sound like the 60s. Yeah. That's the magic in the FYA Garagemaster.

And here are two, more compact versions from Alex. Should be easy fit for 1590A, if you use 9mm pots.