Rangemaster kit — the greenest pedalsmith you’ve ever met

[Pipes]

Hi folks,
         I'm brand new to the forum and new to pedal building. In truth I'm new to electronics. 
I wanted to ask if anybody has tried the rengemaster kit from effectpedalkits.com and what you thought of it. I recently built one.....screwed it up the first time and rebuilt it. The components are all the same EXCEPT the transistor. This one came with a germanium NPN P416b, which I of course fried on the first screw up. I soldered in a socket to try some different silicone transistors and while they work in the sense that I can get a treble boost when turned all the way up, the output is very low. I tried a 2n5088, MPSA13, 2n3904, 2n4401. They all pretty much sounded the same. Any thoughts or tips are much appreciated as I'm about as green as they come when it comes to building pedals. I genuinely would like to learn though.
                                          -Pipes

[patrick398]

Welcome to the forum!

Here is a debugging guide, if you follow it and come back with voltages we'll be able to see if there's something amiss. It's more likely that there's a build error than anything else.

https://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[antonis]

P416B is a Russian P-N-P Ge transistor..!!

Your substitutes are N-P-N so they are reverse biased on the specific circuit..

Try complementary types, like 2N3906 or 2N5087 or MPSA63 or 2N4402 or any of BC556/557/558/559/560


edit: Welcome..!! 

[Steben]

antonis hits nails.
Try "A" types in the PNP range (BC307A, BC309A,BC557A, ....) or BC327-16 for example. They are usually the lower gain type that comes a bit closer to Germanium gains.

You could swap one of the first resistors with a trimpot to establish an optimum bias voltage at the base. This bias shapes the tone of the treble booster for quite a deal. If classically biased to max output, the added "colour" of the RM is reduced.



https://www.electrosmash.com/dallas-rangemaster

[Pipes]

Thanks! Will try both as soon as I can. I do have a 2n3906 I can throw in there and try. The website for EPK said it's a negative ground, but I thought it kinda strange that the kit was only 25 euro. From what I'm gathering, NPN germs are pretty pricy when you can find them. I think I can get some P416b on eBay for cheap. The trim pot idea sounds cool! That the tripe of stuff that I want to learn! However, it may be best to just get it working properly first before I modify anything.

[Pipes]

Ok. I tried the 2n3906. Interesting. When and I play easy, nuth'n, but when I really hammer  the strings, I get a highly boosted treble. Do I just need a lower gain PNP? Wiring otherwise is ok. There isn't that much wiring in this kit! I'll be interested in hearing it with the  new P416b germs when they get here!

[mac]

Hi,
You need a transistor with hfe between 60-90.
If you use silicon, you have to tweak one of the base resistors, for example the one from base to gnd, to set the collector near 6-7 volts. Try 100k instead 68k.

Other low gain Si NPN,
2n2369, many power transistors like Tip31/41, BD175/237.
Si PNP,
Mpsa92, and the PNP version of the ones above.

Power transistors have high internal capacitance, worth a try in this circuit.

mac

[Pipes]

Been thinking about the whole transistor thing while I wait for my P416b to get here. Do you suppose from the description from effectpedalkits.com that they just reoriented the electrolytic caps to get it to work with negative ground? For all my searching I can't find a NPN P416b. Am I right in thinking this would have the desired effect?

[Steben]

found this:

P416b has current gain of 90 to 250

[antonis]

For all my searching I can't find a NPN P416b. Am I right in thinking this would have the desired effect?

If your circuit is designed to work with P-N-P, use P-N-P..!! 
In case you wish to use N-P-N, post a schematic to be guided for respective changes..

[digi2t]

I've found that 2N2904A works well in the Rangemaster. Gain range is in the 70 to 120 range. Only minor re-biasing required.

[Pipes]

Here's a link to the manual. The schematic is all the way at the bottom.
https://effectpedalkits.com/wp-content/uploads/manuals/rangemaster-treble-booster-kit-building-manual.pdf