How can I increase gain on Rangemaster

[FloorIt]

I have completed a build of the Madbean Rangemaster.  It sounds decent but I am surprised at the lack of gain/overdrive.  It sounds like a low gain overdrive pedal with boosted treble.  Is this normal?  How can I get more overdrive out of it?

[midwayfair]

I have completed a build of the Madbean Rangemaster.  It sounds decent but I am surprised at the lack of gain/overdrive.  It sounds like a low gain overdrive pedal with boosted treble.  Is this normal?  How can I get more overdrive out of it?

Yes, this is normal and exactly what it should sound like. It is, after all, a boost. A single transistor stage simply can't distort the signal that much. The gain is pretty much already slammed, though there is a bit more output available if you change the bias (you'd have to either increase the boost pot or increase the 68K resistor, which in turn would mean that you need to change the size of the 4n7 input capacitor to keep the same bass cut at the beginning). If you use a guitar with hotter pickups, you'll get more distortion. If you didn't include the input capacitor switch, increasing the bass at the input will give you quite a bit more distortion. But it's still not going to sound like a fuzz or anything like that. Also, it's made to boost your AMP into distortion, so if you're expecting a ton of distortion based on recordings but you're running it into a clean amp, that's another problem. You need to have your amp turned up loud first and then the boost will give you more dirt from the amp. Or use an overdrive pedal in place of your amp's distortion and use the treble booster to overdrive the pedal.

A final option is to use a boost in front of the rangemaster, but most people find that to sound very harsh.

(By the way, gain does not equal distortion. If you're not getting a very large amount of boost, something else is wrong.)

[FloorIt]

Thanks for the thoughts and info.  Before I dive into possible mods, let's first assess whether it is operating normally.  From what I recall, I cannot get passed unity gain even when the boost control is dimmed.  Is this normal?

Also, I do understand the principle of the pedal providing a distorted/clipped signal versus providing added gain which will drive the amp into clipping.

[davent]

The two i've made and boxed as well as all the messing on a breadboard are well above unity at half way up on the volume knob.

[midwayfair]

Thanks for the thoughts and info.  Before I dive into possible mods, let's first assess whether it is operating normally.  From what I recall, I cannot get passed unity gain even when the boost control is dimmed.  Is this normal?

Also, I do understand the principle of the pedal providing a distorted/clipped signal versus providing added gain which will drive the amp into clipping.

No, this is not normal. Unity gain should be around 9:00 on the knob. Take voltages on all three pins of your transistor and post them. Pictures of both sides of the board will help as well.

[FloorIt]

Here are the voltages for my OC44:
E  -0.535v
B  -0.665
C  -7.51

[davent]

How's the board solder joint on the yellow wire of the volume pot?

Opened up one of mine and measured, set the collector to -7.5 and get base -.96 and emitter -.84, using a Japanese Ge not the OC44 so my voltages may be totally irrelevant.

dave

[mgwhit]

Did you intentionally tweak the R1 and R2 values from those in the build document?  (I know Small Bear frequently provides resistors with their germanium transistors.)  The color codes on yours look like 43K and 2K7 to me.

[FloorIt]

Thank you for the help, Dave.  Under magnification the pot wire joints at the board all look good.

How's the board solder joint on the yellow wire of the volume pot?

Opened up one of mine and measured, set the collector to -7.5 and get base -.96 and emitter -.84, using a Japanese Ge not the OC44 so my voltages may be totally irrelevant.

dave

[FloorIt]

Did you intentionally tweak the R1 and R2 values from those in the build document?  (I know Small Bear frequently provides resistors with their germanium transistors.)  The color codes on yours look like 43K and 2K7 to me.

I'm impressed- you have a good eye!  And you guessed right on the Small Bear supplied resistors.  They are in fact a 43K and a 2K7.  Can these resistors affect gain?  What else could cause diminished gain?

[mgwhit]

I'm impressed- you have a good eye!  And you guessed right on the Small Bear supplied resistors.  They are in fact a 43K and a 2K7.  Can these resistors affect gain?  What else could cause diminished gain?

I'd go with the values that Small Bear provided.    They can affect gain, but I would think a smaller value of R2 would increase gain.  There's not any chance that you have your OC44 in backwards, is there?  I think the collector (side marked with the dot) should be on the bottom.  I can't see yours well enough to tell.

[Bret608]

I think Matt is right about the transistor being reversed. I'd expect to see a red dot on the side facing the bottom. Anytime I've had a build seem like less gain that it should be, this has been my goof-up every time.