Less treble boost in Minibooster

[gutsofgold]

I built my Minibooster on an AMZ board directly from the schematic and I get a little bit of a treble boost. Is this normal? Anyway I can substitute the treble increase for more low end/mids?

I think this would require me to increase C1 to allow more low end in and also increase C2 to lessen the treble boost.

[kurtlives]

Its definitely not a transparent effect (not a boost either). Mine cuts through but doesnt have a ton of treble.

Playing with the input cap seems like a good start.

[Dragonfly]

Hook up a trimpot (wired as a variable resistor) into a cap (maybe .001uf) at the end of the circuit to ground. Use the trim pot to dial out any excess treble signal.


so....

end of circuit -------------------> volume pot
                              I
                              I
                              I
                         trim pot -------> .001uf cap -------> ground

[flo]

http://www.muzique.com/amz/mini.htm#history
C1 (input capacitor) is so large that all lows are already allowed in. It does not need to be made larger.
I do not know exactly what C2 (feedback capacitor) is doing but I'm guessing it is pretty "full range" already because it is large.  
Indeed you could bleed off some high-end from the output with a simple (high-shelving) filter by putting a capacitor in series with a resistor to earth so that they are parallel to the output pot as advised by Dragonfly.

[gutsofgold]

Thanks guys, I'll add the res+cap series in tonight.

[gutsofgold]

So the more I use this thing the more I notice it's not a booster at all, it's really a light overdrive. A good one at that though!

[kurtlives]

So the more I use this thing the more I notice it's not a booster at all, it's really a light overdrive. A good one at that though!

Yep... I was kinda surprised when I fired mine up the first time.

Like I said...

Its definitely not a transparent effect (not a boost either).

[petemoore]

  Dragonfly, that wiring diagram is what I have on my MB.
  I used a 100k panel mount pot and a .1uf [IIR the values correctly], could be slight overkill, but goes from near trebly as without treble control to nice thick tone, it hasn't been left at turned all the way down since I installed it, it definitely gets used.
  Part of the reason for that is because with Fuzz before, it really helps to take some highs out.

[Dragonfly]

  Dragonfly, that wiring diagram is what I have on my MB.
  I used a 100k panel mount pot and a .1uf [IIR the values correctly], could be slight overkill, but goes from near trebly as without treble control to nice thick tone, it hasn't been left at turned all the way down since I installed it, it definitely gets used.
  Part of the reason for that is because with Fuzz before, it really helps to take some highs out.

Yep...

For a more "traditional" tone control, a 100k pot and a .022uf-.047uf cap would work great. I just suggested the .001uf/trim combo for someone who wants the top end rolled off "just a little, but all the time".

You're 100% correct about using it in conjunction with a fuzz...some treble rolloff really helps.

also, if you use a smaller cap instead of the 3.3uf (anywhere from .1uf - .22uf) you'll notice a bit less overdrive, mainly because its not pushing as much low end signal content through. A .1uf there and a little treble bleed on the end (I just use a 220pf to ground usually) makes for a really great "all around" booster.

[gutsofgold]

I'm wondering if I should just keep this stock and appreciate it for what is, a nice overdrive and build me an exclusive clean boost. What would be a more traditional booster - a LPB, Microamp, Mosfet Boost, something else?

[soulsonic]

You could add a resistor in series between the input cap C1 and the Gate of Q2. You could start with 10K and maybe go up to 33K or 68K. This should tame the sharpness in a way that won't make it sound too dark. Then, remove C6 (the 10uF Source resistor bypass cap); this should drop the gain enough that it will be less overdrive and more of a straight boost. You could put that cap on a switch so you can toggle between the two different "modes".

[gutsofgold]

Will be modding this in an hour or two and I'll see how it goes. I remember Jack sending me a "private" site for purchasing the board from him and it had a lot of good mods on it but I lost the link  .

[flo]

@soulsonic: Thanks for the tips!

[ubersam]

I'm wondering if I should just keep this stock and appreciate it for what is, a nice overdrive and build me an exclusive clean boost. What would be a more traditional booster - a LPB, Microamp, Mosfet Boost, something else?

Not sure if you could call it traditional, but the Sparkle Boost is one fine booster.