NPN germanium

[daz]

2 questions.1- do all germainiums come in metal casings? 2-what are some of the most common ones, and specifically one i could find locally like radio shack or local elec stores?
I want to build a dallas rangemaster and thats the only part i don't have.

[nickb]

I think you mean PNP. Quite a lot of the old PNP OC71 types came in a glass envelope will with opaque gloop inside. You could scrape off the paint and turn them into photo-transistors!

I might be called out for heresy but in all honesty it will work just as well, if not better, if you use a modern silicon transistor as they have better temperature stability and more gain. Swap the battery polarity and you can use NPN if you prefer. Play with the the 470K resistor and the volume on your instrument to tweak the sound.

[daz]

Ahhhh, i see now, thanks. I was looking at one that was for use with a NPN, but looking at other schematics they are PNP. Is a NTE159 usable in this circuit? (i have one)

[Steve Conner]

Pretty much any transistor will work in the Rangemaster circuit. They will all sound somewhat different though. Germanium transistors were extremely slow, I have heard it said that they struggled to cover the full guitar frequency range in the Rangemaster circuit, so it ended up more of a mid boost than a treble boost.

[Jazz P Bass]

Nice link: Fuzz Central -- Dallas Rangemaster

[daz]

Nice link: Fuzz Central -- Dallas Rangemaster

Thanks, good link. If i wanna build the original but with NPN instead, that'll work just by reversing the electrolytics and PSU won't it? I see nothing else that could matter looking at those schematics.

[imaradiostar]

You may find that a rangemaster style circuit is a little more fun with a true germanium transistor of the right gain ranges. Small Bear has them pre-sorted for excellent prices. If you want to experiment there are many Germanium transistors on ebay. I have a bunch of old npn germaniums that used to be prototyping stock from a Navy lab which seem to work well but I don't recall the part number. You may find that the Russian npn's on ebay are better quality- I once researched it but have since forgotten the exact number to look for.

As usual, YMMV.

jamie