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I'll do some socketing. Any suggestions for R18 and 19?

Edit - On the tagboard layout the components are lablled. WOuld you be able to point out which resisors I should socket?

Cheers

Hi, see the diagram attached in this message for the positions of R18,R19 and R1. For a bit more gain, change R1 to 470 ohm. For R18 and R19 I wouldn't go below 100 ohm.

If possible, let me know how it works out and sounds 

All the best!

Thanks for this! I've been looking for a new distortion for ages. I put in the parts order yesterday and will get it built (as oper the Tagboard layout) asap.

Thanks again!

You're welcome, have fun!
Also, it does pay to experiment a little with the component values, especially the emitter resistors R18, R19 and the gain of the input amplifier U1a (lower R1 for higher gain).

You're welcome. I needed the bump circuit for another project. It was only later that I wondered what it would sound like in a distortion. Haven't measured base current, but since the base resistors are considerably higher than the collector resistor, probably the collector current dominates. In other words: the transistors work as 'proper' transistors and not merely diodes.

Hi All,

Since there was some discussion on how it works, I drew up a quick schematic.

• Drawing A shows a non-monotinc 'bump' function: for low inputs, the output just follows. Once the transistor begins to conduct, the output will drop with increasing input voltage.
• Drawing B shows the classic 'rubber zener'. It more or less  clamps the output to that voltage which causes transistor to conduct (so it's base is at 0.6V). 
• Drawing C shows combines A and B, by splitting the collector resistor, so you get something in between A and B, depending on the position of the wiper.

The distortion circuit in the Instructables is just drawing C with an extra emitter resistor and mirrored, to accomodate the negative input voltages. The emittor resistors limit the 'depth' of the downgoing slope of the characteristic.

Have fun!

Hi Everyone,

Silver Blues made a stripboard layout at guitar-fx-layouts:

http://guitar-fx-layouts.42897.x6.nabble.com/Instructables-Not-like-a-BOSS-distortion-td38120.html#a38131