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Rangemaster question

Started by reddo, August 05, 2011, 04:01:29 PM

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reddo

I built my first Rangemaster and something seems off. When it is on I have less than unity gain, is this normal?

jkokura

Depends on where your pot is set, and some of the values you used. If I remember right, unity is at about 11PM on mine...

Jacob
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dwstanford

You should have tons of gain with a rangemaster.  Make sure your pinouts are correct.  If its a pnp germanium, you should either have a red dot to mark the collector or a metal tab to mark the emitter.

reddo

Thanks guys. The pot is cranked all the way, I used the values from the build doc. I first tried it with a low gain si pnp then the ge pnp same deal with both. Next step is to triple check all the component values.

jkokura

Also see if you wired your pot backwards. If you turn it down, does it get louder?

Jacob
JMK Pedals - Custom Pedal Creations
JMK PCBs *New Website*
pedal company - youtube - facebook - Used Pedals

gtr2

Quote from: dwstanford on August 05, 2011, 05:34:21 PM
You should have tons of gain with a rangemaster.  Make sure your pinouts are correct.  If its a pnp germanium, you should either have a red dot to mark the collector or a metal tab to mark the emitter.

This ^
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dwstanford

If your transistor pinout is correct, check the voltage on the collector.  You should get around 6.5 to 7.5 volts.  If its way off, like 2 or 3 volts, you may want to double check your component values.  Luckily there arent very many.  This circuit works well with transistor gains around 100.  If your transistor is much higher for instance, you may need to alter the 3.9k resistor value slightly to bias correctly.  This should not affect the gain though.  It should still be very loud even if the bias is a bit off. 

bigmufffuzzwizz

I agree this sounds like when I've put transistors in backwards. With a heavy fuzz it will kinda sputter and decay really quickly. You should definitely be getting a huge boost to the point of over-driving your amp.
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reddo

Got it working. I tried an AC128 I had and everything was fine. I had the first one I tried marked as 80 - 100 hfe perhaps it isn't.

dwstanford

Great.  Glad you got it going.  Now go blow up some amplifiers.  8)

bigmufffuzzwizz

Quote from: dwstanford on August 06, 2011, 08:51:38 PM
Now go blow up some amplifiers.  8)

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