AMZ mini booster

fuzzo · August 29, 2009, 10:39:30 AM

hi guys,

I've just made an AMZ mini booster, sound good in clean boost but when I crancked up the gain knob (voltage divider in front of the circuit, like the one used in fat boost fulltone) the sound becomes really ugly like if the transistors are diying.

I'm little bit desapointed 'cause I read a lot of good thing about it.

I did something wrong or it's the regular sound produced by the circuit ?

(I used J201 and 2N5457)

Paul Marossy · August 29, 2009, 11:24:28 AM

It sounds like something is not right with your build. Mine doesn't exhibit any behaviour like that. Sometimes the variability in JFETs can cause weird problems, maybe your problem is due to that.

fuzzo · August 29, 2009, 03:24:06 PM

Actually I tried different JFET I've and nothing seem to be wrong. Maybe I just don't like the sound

But with all good things I read about that schematic I'm little bit in doubt

(But I looked for more a low drive pedal than a pure booster)

The BIAS2 doesn't use two mini booster stage to create a kind of "plexi" distortion ?

So, maybe in puting a simple jfet boost (AMZ mosfet boost) in front of the mini booster I could have what I want.

FiveseveN · August 29, 2009, 07:16:14 PM

What are you running it into? Maybe it's the clipping of the next stage you're hearing.

fuzzo · August 30, 2009, 07:07:23 AM

Just the guitar plugged into the circuit .

sed · August 30, 2009, 07:17:49 AM

But what did you plug the circuit into? An guitar amp, sound card, mixer, hi fi amp etc ? The mini booster provides a huge volume boost IMO which could make a sound card or mixer or even a guitar amp distort in an unpleasant way.

Daniel

fuzzo · August 30, 2009, 07:31:44 AM

a guitar amp of course.

Well, I've just tried putting a AMZ mosfet boost before that AMZ mosfet booster and that sounds nice, very different of AOP ovedrive , a little bit "fuzzy" . Do you think the sound will be different with two AMZ mini booster in cascade ? the one boosting the other.

aron · August 30, 2009, 08:01:07 AM

>Well, I've just tried putting a AMZ mosfet boost before that AMZ mosfet booster and that sounds nice, very different of AOP ovedrive , a little bit "fuzzy" . Do you think the sound will be different with two AMZ mini booster in cascade ? the one boosting the other.

We have done this long ago with multiple circuits. Check out the various mini-booster circuits that have been done long ago such as the Booster 2.5, BSIAB etc... and check out the Wiki, especially the simple mods section.

Paul Marossy · August 30, 2009, 09:07:46 AM

Quote from: fuzzo on August 29, 2009, 03:24:06 PM
Actually I tried different JFET I've and nothing seem to be wrong. Maybe I just don't like the sound

But with all good things I read about that schematic I'm little bit in doubt (But I looked for more a low drive pedal than a pure booster)

IMO, the AMZ Mini-Booster is a booster that will give a very slight overdrive when pushed, when all by itself. IME, it really works much better in conjunction with something else.

fuzzo · August 30, 2009, 01:15:12 PM

I could reduce the power suply comming into the drain via a pot. to increase gain ? I beleive I saw a Orman's page about that with LED.

EDIT :

I found it :

http://www.muzique.com/news/mini-booster-fat-and-fatter/

actually I could do the same thing with a pot. I guess.

corona blue · March 05, 2010, 04:03:54 PM

Greetings all-
I realize this is an old thread, but for the sake of those searching for answers to this issue, I have found on circuits like the Mini-Booster that the value of the source resistor makes a huge difference. A 10k trim pot or even a 10k linear taper pot mounted on the box can give you a wide range of gain control. Similar in concept to the cathode resistor on a tube triode gain stage.

Hope this is of some help.

CB

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AMZ mini booster