Onboard distortion for bass guitar, Questions?

[killerhintz]

  Hello, this is my first post, i figure someone here might be able to help me, ive been playing for almost 20 years, and am taking my first baby steps in learning about electronics and (schedule permitting) building basses, ive asked around about this, and have not gotten any answers, i recently purchased a bass booster unit and 250k boost volume from neal moser,  my goal is to have a fairly simple electronics setup, volume, tone, boost volume, boost switch, and a modified varitone switch, i want to be able to switch the boost on and get instant preset bass distortion/overdrive, or at least controlled by the boost volume, so i did some research and found a product called the Black Ice, and a few different diodes that can be hooked up to your tone, the problem is you have to go counterclockwise to get the overdrive effect, and i own a 81 mockingbird that has a boost with a boost volume, and when you turn the boost volume all the way down you lose all the way to zip volumewise, so that would mean i would need a seperate boost any ways   So i called neal moser and told him what i wanted, and he said that no bass player ever asked him for an onboard distortion connected to the boost function, so i asked if there was any cap i could connect to the boost volume to at least boost treble, and he said he could make a switch for that but it would be seperate from the boost, and he said to experiment with different capacitors to find out which one would do that, so i dont think thats the answer for me   any ways i just want either a preset onboard bass distortion connected to the boost, or at least one that connects to the boost volume (increasing clockwise) i know this forum is for stompboxes, but i figure someone here might have some ideas so if someone here could help me here, i would really appreciate it!!!

[petey twofinger]

i would start with a bazz fuss .

https://www.google.com/search?client=opera&rls=en&q=bazz+fuss&sourceid=opera&ie=utf-8&oe=utf-8&channel=suggest

[Earthscum]

23 years on bass here (what, is it a 19 year mark or something? I started doing this about 3 or 4 years ago, lol!). Absolutely agree with Petey... bazz fuss.

I built the one using 2x 2N2222 to make a darlington, but I would recommend either a 2N5089 or MPSA13 (or A14) just to make things easy. All I have is a volume, and it's pretty much my go-to rip distortion. It still sounds like a bass, and can get a nice scream on heavy hammering, but still not just that pure distortion... very usable in multiple settings, even have played it while all the guitars were acoustic and didn't overpower or stand out too much.

I play Ibanez GSR205 into a Peavey TNT 115 BW, and have everything fairly flat (I like the sound of Ibanez basses, even their cheap ones. They play well with Peavey gear).

[runmikeyrun]

another bass player chiming in for the bazz fuss as first project.  The darlington definitely sounds better, and if you want more gain put two in series.  Use sockets for the transistors, coupling capacitors, and diodes to make changing them easy to customize your sound.

[ashcat_lt]

I have always been against the idea of onboard effects.  It seems to me like a pedal would just be more flexible.  You could use it for more than just the one instrument, it would be easier to power from a wall wart (I hate batteries!), and you would be able to switch it on or off without having to take your hands away from playing.  But that doesn't answer your question.

The other posters have suggested you build a complete fuzz circuit.  It's a fairly simple circuit, and is said to sound great.  Doesn't answer your question either.

To answer your question:

There's really no reason you'd have to use the variable resistor in a "black ice" type thing at all.  If you stick a back to back pair of diodes across the output of your booster circuit you will get overdrive/distortion.  The amount of distortion you hear will vary with the gain knob.  Turn up the booster, you get more distortion.

If you want to just convert it from a "clean" boost to a distortion, then it's that easy*.  You'll have to be a little careful with how you wire the switching to make sure that when you turn off the boost you take the diodes with it.  That shouldn't be too tough.

OTOH, if you'd like sometimes to have "clean" boost, and at other times to have distortion, you could put the diodes on their own switch.  An SPST toggle is all it would require, though a DPDT on a push-pull pot could be used, to avoid drilling holes.  

Or you could use the variable resistor config which you've seen elsewhere.  The direction of rotation here is arbitrary.  If you want more distortion as you turn the knob "up", just use the other outside lug!  For a linear pot there will be no difference in taper.  A log pot wired this way may not give satisfactory taper, so if you think you need that, you'll have to find an anti-log pot.  They're out there.  I think this is just redundant.  The amount of overdrive is already controlled by the setting of the boost, do you really need another control?


* a couple complications:

1) When the diodes conduct, they act as a dead short across the output of the booster.  Unless it is built to protect itself from this situation, it could become unstable or even destroy itself trying to source near infinite current!  It should be built to protect itself, but without knowing for sure you'd probably want to put a 560R or 1K resistor in series with the output before the diodes. 

2) You may find that the diodes produce more high harmonics than you want to hear.  It could come out "fizzy" or "harsh" or whatever.  Running it into a typical modern bass amp - which generally has much better high frequency response than a typical guitar amp - will make this much worse.  You may want a cap to ground alongside those diodes to help tame this a bit.  The value would be a subject of experimentation.

[Earthscum]

Honestly I have been seriously considering building an onboard BF. The battery lasts forever and I use it even to drive other pedals. It just sounds RIGHT to me. One option I am considering is being able to run it from one or the other or both pups for a sweet blending option.