Author Topic: Noise when effect is on  (Read 3159 times)


Noise when effect is on
« on: September 30, 2006, 04:54:22 PM »
I built the npn booster and it works, but it's pretty noisy when the effect is on and the guitar is silent.  Does anyone have tips for lowering noise, or is this pedal typically noisy?  Should I try to shorten the length of the wires? 

Also, what is the best way to add a tone control to the booster if I want to be able to turn down some treble?



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Re: Noise when effect is on
« Reply #1 on: September 30, 2006, 06:04:32 PM »
Hmm, how noisy is it? Some hiss would be normal; not likely to be evident when jamming with others.  Sorry to sound like Ed McMahon or something, lol...but, any amplification ckt is going to add's present at the input, and gain will only increase its apparent level.  Given your name, Strat, you're using single coils? Those pick up noise like you wouldn't believe!  Any nearby sources will get in there (light dimmers, monitors, etc.) and then be amplified.  +1 for guitar shielding, too. Have you tried using the boost with a humbucker equipped guitar?  Sorry if you've already come up with that  ;)  How does it sound with no guitar cable plugged into it?  Easy way to eliminate the pedal if it's coming from the axe...
So, provided you're as "noise free" as possible at the input, you could check: It's in an all-metal box, right? What transistors did you use? 2n5088's give lots of gain, but are noisier than the 5089's.  If you socketed the tranny's, swapping them is no problem.; esp. if something got heat-damaged while soldering.   Are all the grounds in the box going to just 1 point on the board, where the battery" - " terminal connects?  You're sure there are no shorts anywhere? 

The jacks are of good quality, each grounded back to that 1 point? (search "star grounding" for more info).   Are the input & output caps the values required?  Is the pot(s) new, in good shape? Shortening leads is always great, if you can, as it using shielded internal wiring on the jacks (maybe overkill).

For tone control, look up "stupidly wonderful tone control" (SWTC)...both here, and on the Ampage would work well with the npn boost, just tacked onto its output.  I believe it has the balls to make up for any level loss (insertion loss, they call it).  Check it out.

Let us know if any of this helps!   :D
MXR Dist +, TS9/808, Easyvibe, Big Muff Pi, Blues Breaker, Guv'nor.  MOSFace, MOS Boost,  BJT boosts - LPB-2, buffers, Phuncgnosis, FF, Orange Sunshine & others, Bazz Fuss, Tonemender, Little Gem, Orange Squeezer, Ruby Tuby, filters, octaves, trems...