Wednesday 27 September 2017

Nine Volt Nirvana BrontoBoost

Next up of the Nine Volt Nirvana pedals is the BrontoBoost. From Joe.

The new Brontoboost is a two stage booster/fuzz/OD/Dist unit that has a ton of different tones in it, all good! It goes from awesome treble boost like a British top booster, to fullrange boost, to very fat fuzz and everything in between. The fuzz can be set to 'sick', which sounds like an amp on the verge of meltdown! The Brontoboost features tremendous sustain, with a fuzz character that is textured and harmonically rich without sounding like existing fuzzes. Be careful, playing in this compressed , swirly fuzz mode can be addicting, and might bring out a whole new side to your musical expression! "The Bronto is a versatile beast, and has a character unlike any other pedal on the market. Some people simply don't like it, others think it is the most brilliant thing they have ever played! Weird. It does four things, and all of them very well:
  1. Cleanish boost [treble boost or full range]
  2. OD, like a TS, but with a much more open and natural feel - responds to your playing in a very satisfying way. Wider freq response than a TS or most other pedals on the market due to the 'quad cap' circuit path - this adds dimension to the freq response.
  3. Fuzz - mild fuzz all the way to 'amp meltdown' sound. different than any other fuzz I have heard, - compressed yet articulate. Smooth yet alive. Sustain and clarity amidst the fuzzfrenzy . Weird but beautiful.
  4. Tube amp simulator. I use mine on low volume gigs to replicate the breakup of a tube amp. People are amazed a the tones that are achieved at low volume with it. Like our favorite all time great rock guitar tones but at a very reasonable volume!
The other great thing is that at all settings, it retains an incredible 'gain' control - your guitar 's volume knob! I use the Bront on about 80% of all my guitar work these days due to this versatility. Swiss army knife of preamp/OD/Boost/Distortion/Fuzz."
Quick note: Q3 is Ge, so I assume you can sub the 2SB54 for any other PNP Germanium transistor.



25 comments:

  1. Thanks Zach.
    What is the switch supposed to do ? I guess a DPDT would be fine

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    1. the schematic calls for a 3pdt, and that's what i would use TBH. the switch controls the number of gain stages, 1 or 2.

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    2. Ok thanks. A 3pdt would be usefull to wire a led if used as a stompswitch (which could be nice for added gain stage). Otherwise if lugs 7/8/9 are unused a DPDT should be fine

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  2. Replies
    1. Not sure cause the shcematic only lists the pot values. I would try linear, and if it the pot travel isn't good I would try a log taper.

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  3. Hi Zach,
    there seems to be some errors, obvious Volume2 should be Volume1, Volume3 is one row to high, Tone 4 5 6 does nothing (maybe only Tone4 should connect to the board and I cannot find the, hm, exit of Q1. Or am I wrong? Looks very interesting.

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    1. The 3.3uF from base of Q2 should connect to Tone 4 and i understood we get the Signal at the emitter of Q1

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    2. hey man. yea there's a few errors. just ran through the whole layout again and made corrections, so it should be good to go now.

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    3. Thanks Zach! Build it yesterday on the spreadboard with npn, doesn't sound to bad. Maybe i try again with pnp and i should get some Germaniums.

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  4. It says -9V. Does this mean its an effect with negative voltage? Does it need a voltage convertor? Leon, the Netherlands.

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    1. That's what it means. Generally with pnp, they are negative ground effects. Although, there are exceptions. Yes, you need a converter. Lt1054, 7660.

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  5. Pretty interesting. If I used a +9v supply, changed the pnp transistors for npn devices and turned the polar caps around, it should be good to go, yeah?

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    1. you can do that or use an offboard inverted or just connect the +9V to the ground on the board and the ground to the -9V. if you do option 3 you can not daisy chain the effect with +9V effects.

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  6. Well, as I have 2n2222 and npn ge in my stash of bits I'll go that way. Thanks for the confirmation.

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  7. Great work Zach, but really struggling to see all 12 cuts any help pinpointing them all? (Not a big fan of new layout software - miss the old style layouts with bare board to the side)

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  8. Its ok found them zooming in on phone sorry

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  9. If that trimmer was external would it go 1-2-3 from top to bottom? And what would you call that pot?

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    1. Honestly I'm not sure. The middle leg of the trimmer will be lug 2 of the pot regardless. You can take and wire it up as you described and if it's backwards just flip lugs 2 & 3.

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  10. Hi everyone, I've just finished building one of these, it works well but despite being at the highest level, the output volume is anyway lower than the volume in bypass

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  11. Hello, is it verified as it is ? Its working kinda... but when i push the other switch i cant get any signal out... (GB its working but A not working...) Where to look ?

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  12. The schem this was taken from has an error.

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    Replies
    1. where's a correct schematic then?

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    2. The one schematic for this effect I could find on the revolutiondeux blog has the Q2 base directly connected to the -9v, which seems odd. I am wondering if the connection should be made with something like a 470k resistor instead. Thankfully, on this layout, all you would have to do is swap the jumper off the Q2 base with a resistor.

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    3. I just built the boost section (Q2) by itself on a breadboard. Sure enough, it does not work with the transistor base connected straight to the voltage. Replacing that connection with a 470k resistor results in a clean boost, though I cannot be sure if that was what the designer intended or what that would sound like as part of the complete circuit.

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