Rangemaster Boost Knob?

[jaydiggity]

I built myself a modified Rangemaster last week. It's very close to spec, but I built it into a mint tin with no knob and no switch. Instead of a pot, I directly connected the collector to the output cap and put a 20K resistor between -9v and the collector... I really like the sound a lot. Now I'm thinking about building a version in standard stomp format. But what I'm wondering is this... how much does the boost setting affect the tone of the pedal? Obviously it attenuates the volume, but it also changes the current to the collector, right? What does that do? If I were to build this the way I'd want to use it is to kick it on for a solo to get a little more volume and breakup and sound a bit more "hot". But I'm wondering if it'll sound way different with the boost dialed back some. On full boost the volume gain is way too much! Or maybe the way to go would be to keep the 20K resistor in place and wire the pot as a normal volume knob between the collector and the output cap? Any thoughts?

[smallbearelec]

When you are talking about tweaking the bias in a way that curls your fur, it's time to get out the breadboard! You may also want to add a "faux variable input capacitor" (Fig. 20 in the link below) or a larger or smaller output cap. Infinite variations possible depending on your taste.

Note that lots of reasonably-priced NPN germanium is available, especially if you are willing to experiment with Darlington pairs (Fig. 21 and following)

http://diy.smallbearelec.com/HowTos/BreadboardRMs/BreadboardRMs.htm

[Passaloutre]

It shouldn't sound any different at different settings, just louder/quieter. At least mine doesn't. The collector always sees the same voltage.

[jaydiggity]

Thanks Pass that's what I was wondering. Small Bear, cool to hear from you, I bought the transistor from you. I got a Japanese one and I think it sounds great. It biased right to 6.8V with your resistors, but I ended up installing a trimmer anyway to mess around :-) It's amazing the difference between playing through a solid state amp (which is what I test on at home) and a tube amp. It sounds harsh with a velcro ripping sound on the decay using the former. But on the tube amp it sounds ultra smooth with a wonderful bite on the attack. I'm not exactly in the mood to do that level of experimenting at the moment, but of course that'd be the "right thing". I still don't understand why the collector is connected to power via the pot though instead of a static resistor.

[antonis]

I still don't understand why the collector is connected to power via the pot though instead of a static resistor.

Output is taken from pot's middle lug so it acts as a variable volume pot..