NPN Boost sounds a bit like a wah?

Started by Voxin, December 20, 2007, 01:08:25 PM

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Voxin

I just finished the NPN Boost build and everything works, but I have noticed that the tone is not as clear as I would like it to be (a bit muffled actually).  I have noticed that when the pot is maxxed out, the sound is kind of like when you engage a wah about half way.  It's very subtle but definitely noticeable.  The boost portion of the circuit works just fine but should I substitute a resistor somewhere to get rid of this sound?  Is it the pot?  Any help here would be great!

Many many thanks!

John Lyons

Print out a copy of the schematic or layout diagram (did you build it on perf, vero or PCB?) and trace the diagram against the board with a colored pen. Make sure you have the Electrolytic capacitors in with the polarity correct. Check the values of the caps to make sure you used the correct value. Measure the resistors with the power off to see if they are the correct value.
Get a magnifier (glasses or a jewelers loupe) and make sure you have no solder bridges or wire hairs across solder pads or components where they should not be.
When you find the mistake you'll have a good laugh, slap your forhead and then enjoy your new pedal.

John

Basic Audio Pedals
www.basicaudio.net/

Voxin

I cleaned up the solderjoints and subbed the .1uf input capfor a .01uf andit nowsounds great.  However, is there a way I can adda slight bit more volume to the pedal?

Thanks for all of your help!

RedHouse

Quote from: John Lyons on December 21, 2007, 02:36:00 PMWhen you find the mistake you'll have a good laugh, slap your forhead and then enjoy your new pedal.

Yeah, didn't Dire Straits do a song about DIY electronics?:

There must be sunshine after rain
There must be laughter after pain
These things have always been the same
So why worry now?

petemoore

is there a way I can adda slight bit more volume to the pedal?
  IIRC that's an NPN Si Bootstrapped for gain, should make big boost over unity.
Convention creates following, following creates convention.