Need Help with Rangemaster, Again...

Started by Herec, July 16, 2006, 10:12:23 PM

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Herec

Just built another one up upon assuming I had fried the first transistor since I could not get the collector voltage to go past 2.7

I just built a completely new build, new parts, and found...

C = 0.75

B = 8.21

E = 8.12

I used Dragonfly's vero layout. In place of the two biasing resistors I have pots (maybe the wrong type?, used 10K and 100K).

Turn it on and... fizzy fuzz type stuff. Its ok, not great though, doesn't seem to have alot of Db boost even on full.

WHAT IS GOING ON!

Should I use PC Board?

hairyandy

I don't think the board would make any difference.  Vero is fine and I've built a ton of these on vero for people.  Here's the layout that I made for mine using Bancika's program:

http://aronnelson.com/gallery/albums/album26/Rangemaster.gif

What I would suggest is to first make one without trimpots.  Just use the original resistor values (3.9K, 68K and 470K) and try it that way first.  My rule of thumb is what sounds good is good, regardless of whether the voltages are correct.  Usually, if your transistor is OK, you'll be close enough in the ballpark that it will at least sound close to what a Rangemaster is supposed to sound like----ie:  a pretty loud, trebly boost that begins to distort around 1:00.  Once you get one that works and sounds decent, try replacing just the 68K resistor with a 100K trimpot and set it where it sounds best.  You should get a pretty obvious sweet spot and at the lowest extreme it will completely shut off the signal so you can hear where it gets to the sweet spot.

Try that and be sure to check and double-check your wiring and layout and mind your polarity!

Good luck,
Andy Harrison
It's all about signal flow...
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