New dist schematic/PCB...BuzzTone

[brett]

Hi.

Working on a Bosstone led to this circuit http://members.optusnet.com.au/~jethro.dog/mypic135.jpg (The PN100 can be almost any NPN Si tranny and the PN200 almost any PNP Si tranny).  The 25k(B) pot cuts those annoying high-frequencies that sometimes make you feel like your ears are gonna bleed.  It's a subtle, but useful effect.  For the experimentalists, there's lots of options for playing with that section of the circuit.

This distortion is almost as smooth as a fuzzface, but also almost as rock-n-roll as a Distortion+.  I've tried LOTZ and LOTZ of distortion pedals, and consider this as good or better than most others.

You might be wondering where the "Drive" control is.  That's done from your guitar's volume control.  The circuit's gain doesn't change - just the amount of signal you feed it.  As shown, the circuit is medium gain - if you want higher gain, simply replace the 220 ohm resistor with a smaller resistor, or a jumper (and, of course, you'll need a high hFE transistor as Q1).  Oh, yeah, you MUST orient the diodes as shown in the schematic and parts overlay.  Large signals will be very assymetric before they get to the diodes, and need to hit the assymetric diodes in the same orientation (I don't think that was very clear, but never mind).

Anyway, try it.  It's very cheap, not too complex, and IMO sounds very good.    

Here's the PCBhttp://members.optusnet.com.au/~jethro.dog/mypic136.jpg and the parts overlay http://members.optusnet.com.au/~jethro.dog/mypic137.jpg.

[lightningfingers]

I just breadboarded it.

Very nice, sweet distortion, this ones definately goin in a box  :mrgreen:

Thanx for the link brett  

[Arn C.]

Lightningfingers,
   What transistors did you use?
Thanks!
Arn C.

[Mark Hammer]

So, a Bosstone with asymmetrical clipping and a little more headroom, plus a 2-pole LPF on the output?  Daddy like.  Simple.  Smart.  Cheap.

Good on you, mate!

[lightningfingers]

What transistors did you use?

2N3904 and 2N3906

i'm gonna get me some 5087s and 5089s tho :twisted:

[Nasse]

:shock:        :shock:

[Arn C.]

Thank You for replying!!!    Thank you Brett for the new circuit!!!

Peace!
Arn C.

[phillip]

Very nice Brett!  I've been waiting for someone to tweak out the little Bosstone, and you did it very nicely!

A couple of months ago I was going to start messing with the Bosstone a little, but I once again got distracted with a ToneBender and now I'm on the Fuzz Face again  :shock:

Thanks for your work and for posting your schematic and PCBs!

Phillip

[StephenGiles]

Great stuff  -  I'll breadboard it and see!

[brian wenz]

Hello Hello Brett--
     Was wondering when you'd get to the Bosstone.......!!
 Thanks!
Brian.

[brett]

i'm gonna get me some 5087s and 5089s tho

The gain is actually controlled by the LOWER of -
1. the hFE of Q1, or
2. the ratio of the 2 collector resistors, divided by the emitter resistor (of Q1)

In the standard layout, the gain of Q1 is set to about 160 because (2) above ((18k+18k)/220)) is less than (1) (200 to 800) for modern transistors.

So increasing the hFE of Q1 will have almost no effect unless you also reduce the emitter resistor.  

I tried it with a PN100 transistor (hFE=380) and a jumper in place of the emitter resistor (for a gain of about 380), and it sounded semi-demonic  :twisted: .  Not as wild as a Blackfire, but still quite sensitive to touch and capable of plenty of feedback.  Not the sound I was searching for, but other people might like it.

Thanks to everyone.

[MartyB]

Looks to be a tempting build.  Any sound samples planned?

[brett]

I only have very basic recording gear (ie a PC with CoolEdit), but might get something recorded over this coming weekend.  In the meantime, I'd describe the  sound as kinda like a "mellow" Distortion+.  There's some tones a bit like the Axis or other old fuzz circuits.  It's designed to fill the niche between mild (and flabby) and wild (and feeling like your ears will bleed).

cheers

[Marcos - Munky]

Hey Brett, could you record some artificial harmonics with it in the soundclip? I'm searching for more distortion tones, but I need something that sounds cool with hartificial harmonics, because I use them a lot.

[brett]

Hi.  I'll try some artificial harmonics, but I'm not much of a guitar player.  I learned artificial harmonics many years ago (25!!) in the style of Steve Morse (pick in the thumb and middle finger, forefinger on the string over the fret).  The more popular Billy Gibbons style (often called pinch harmonics I think) is something I've never tried, but it might be fun.

cheers

[Marcos - Munky]

I didn't tried in the Steve Morse way, but I will try it today . I believe the Billy Gibbons way is faster, because you don't need to change the fingers that holds the pick, but you can learn to hold the pick with the thumb and middle fingers.

[Tony Forestiere]

Not to go OT...but i find the "pinch harmonic" method the easiest and fastest. Hold the pick with the thumb and forefinger, strike the note sharply with the edge of the pick slightly off axis, and immediately attempt to slightly damp the string with the meat of your thumb. Takes practice...but well worth it!

Take care,
Tony

[petemoore]

Choke up on the pick, so it's only sticking out of thumb and 1rst Finger, quickly rub your thumb across the string following the picks twanking, in a kwik motion, don't hold it...you have to set off an 'inbetween normal pick and muted type vibration...not really a muting...have to hit the string hard enough to get it going, but as the thumb just grazes it...harmonics.
 Some people have a tuff time with this because of the way they hold the pick, the kwik motion, etc. it's best done as a feel thing, there's really no way to look at what someones doing to get it, the movement is developed by feel, trial / error, and hand training.

[petemoore]

OF course I messed with it a little bit...
 First I assembled it. Works PDGood.
 Then I tried all kinds of mods on it. One being an LPB in front of it...Small input cap/BCxxx Transistor.
 Then I tried all combonations of
 Q1
 Bc 108 thick [muddy?] sounding
 Bc109 I like that
 2N5089 More gain and high end for sure with *
 2N4904 / 5088
 PN100 suprizing gain level when compared to DMM hfe readout
 * means the Q1 emitter grounded...yep raises Q1's gain.        
 Q2
 2N3906 does well had only one [it got hot without the 18k near PS diode]
 2N4907 different close to 3906
 A marked '1059'  [Probly came in RS 3906 pack]  higher gain more highs
 AB175 [Ge] Great OD with no diodes, gets mushy cool tho with diodes
 
  Then the diodes/end Circuit shaping caps.
 Tried no diodes, 2x 4148 each way, like schematic, 1x4148 each way etc. also...
 I socketted the 2N2 cap between the 10k's, adding diodes here can be tried...IIRC 2x 4148 here and 2X4148 in the diode position with a small cap is the way I have it now.
 Even tho I departed somewhat from the circuit, [please excuse me] it is a great 'perfsockets' or breadboard circuit, sounds quite good many ways including like the schematic.
 I replaced the 18k Collector resistor on Q1 with a 20k trimpot [unnecessary].
 Very easy, fun circuit, I'm planning more extensive testing in the near future.

[brett]

Pete said

PN100 suprizing gain level when compared to DMM hfe readout

that's because one of the cool things about this circuit is the way that the collector of Q1 is tied to the base and emitter of Q2 (kinda like the mu-amp for JFETs).  I don't really understand the detail, but Q2 is a variable load and emphasises the voltage swing on the collector of Q1 and the combined gain is higher than the gain for Q1 alone (by a factor of about 2).

cheers