AMZ Mini Booster questions

Discussion in 'Burnt Fingers DIY Effects' started by stax, May 24, 2009.

  1. stax

    stax Tele-Afflicted

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    Hi all
    My next project is gonna be an AMZ mini booster, you can build different versions of it and I’m going for the clean as possible options as I have a pile of od pedals already.
    I don’t use a lot of pedals so it will be the booster into delay into amp, (maybe add od on occasion) and they all sit on top of amp so no long cable runs.
    Any opinions on whether to go for the buffered or classic un-buffered version and also which transistors to seek out for the best clean sound.
    Thanks in advance.
    Stax
     
  2. mmaatt

    mmaatt TDPRI Member

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    Hi,

    Just got my pcb yesterday, I'm building mine with J201's. That's the recommended for the standard version and I used a J201 in a Tilman Preamp I built, gives a great tone (very easy to build).

    As for buffered version, I'm going to run my Tilman infront, so don't need the buffer, just a bit of boost.

    I'm putting a DIY Electra Distortion and the above two into one box with true bypass on the booster and distortion.
     
  3. RomanS

    RomanS Poster Extraordinaire

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    All I can say is that mine is FAR from clean...
     
  4. stax

    stax Tele-Afflicted

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    Yes I read your post after I started this one; I thought you sorted it out?
    Stax
     
  5. RomanS

    RomanS Poster Extraordinaire

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    Yes, but that took some experimenting & modding...

    Now it only has a hint of grit left (though I guess with a humbucker-guitar - which I don't have - it would still be dirty...) - before the mods, in stock form, following the schematic, it was far from clean.
     
  6. BrianF

    BrianF Friend of Leo's

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    I've built several of these JFET booster circuits and every one has been crystal clear clean, without even trying. No coloration of tone whatsover. Which schematic are you all using?
     
  7. RomanS

    RomanS Poster Extraordinaire

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    I used the original one from Jack Orman's website (also got the PCB board from him).
     
  8. stax

    stax Tele-Afflicted

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    I also ordered the board from Jack Orman's website and he gives you a link to a build thread in which the builder recommends using 2N5457 transistors yet most people seem to say the J201 is the way to go.
    I’m gonna follow every example of keeping it clean i.e. no C3, bigger value R3 (maybe 10k) J201's and also run it on 12v and see how it sounds.
    Anyway I wont get the bits for a while so plenty of time to think about it.
    Stax
     
    Last edited: May 25, 2009
  9. EW57

    EW57 Tele-Meister

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    Was this with single coils or humbuckers? If it was 'buckers, what schem are you using?
     
  10. wnorcott

    wnorcott Tele-Holic

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    If you want as clean as possible I recommend you should build the AMZ MOSFET boost not the Mini Booster. The MOSFET boost is very clean and has a lot of boost.

    Bill
     
  11. BrianF

    BrianF Friend of Leo's

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    Single coils...I never play a humbucker...

    This is the circuit. BTW this originally came from a National Semiconductor Apppliction note for JFETs

    [​IMG]

    I don't recall using the c6 10uF cap though...seems like this wasn't there before. I have to check my own schematics..
     
  12. BrianF

    BrianF Friend of Leo's

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    Yep...my schematic used NO C6 cap....and I used C2=1uF....C3=0.1u Q1,Q2 are J201
     
  13. cpeters01

    cpeters01 Tele-Meister

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    I did the generalguitargadgets schematic for the boutique boost on a perf board with a 2.2uF in the C2 position and the 5457's, No C6. It is really clean and the tone circuit gives it a little more control. Works for me.

    sorry they don't like the link being posted but do a google search and you should come up with it.
     
  14. cpeters01

    cpeters01 Tele-Meister

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    and...I omitted the input gain pot as well...
     
  15. MEINSHNAKE

    MEINSHNAKE TDPRI Member

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    If you are looking for a clean boost, may is sugest the lpb2... on a cleaner setting gives huge volume boosts, but when you are playing heavier tones turns into an overdrive.
     
  16. stax

    stax Tele-Afflicted

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    Finished the booster using all the component and voltage values for the cleanest sound apart from R3 where I could of used 10k but only had 6.8k in stock.
    It sounds just ok, but even just using it for the slightest boost for solos it adds a buzzy fuzzy sound on the bass notes (Tele with Keystones)which I’m not keen on.
    This is more noticeable on the 18watt amps I tend to favour for gigging rather than my 40watt pro reverb.
    My GGG bluesbreaker set to max level and the gain turned up just enough to boost overall level was by far a better sound.
    Looks like I’ve built another od and not the clean boost I wanted.
    Stax
     
  17. RomanS

    RomanS Poster Extraordinaire

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    Seems like yours matches my experience...

    I'll probably replace mine on my board with a Zoom PowerDrive - a so-so overdrive that is THE BEST clean booster I ever tried, with the gain turned down all the way; completely clean, and very fat sounding (but with bass and treble pots, so you can tailor the tone).
    It's about 3 times larger than my mini-boost, but I'll bite that bullet, because it sounds so much better...
     
  18. pgambon

    pgambon Tele-Meister

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    If it's a clean boost, the signal going in should match the signal going out only larger. If you up on electronics speak, it should be a pure sine wave coming out. If its "clipping" then it's not a clean boost and I'd say there's a problem, probably not with the design but maybe with the Jfets or r/c values. Another thing to consider; it may be a boosted sine wave coming out of the circuit but it could be pushing your amp into clipping (gritty sound etc.).
     
  19. RomanS

    RomanS Poster Extraordinaire

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    Well, in real life that is VERY RARELY the case - most boostersalter the signal/tone significantly; many touted as "fat" add some clipping; most praised as "transparent" really make the treble frequencies stand out (either by upping input impedance, or by slightly cutting bass).

    Very few boosters really just make the signal louder - on I just found is the Zoom PowerDrive - which is actually an OD-pedal, but with the gain pot turned down all the way, it is a totally clean booster that does not change the tone/signal at all - GREAT!
     
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