Background
I love the Parentheses Mini (aka Life), but bringing the octave in makes it too harsh and trebly for me, so I've been experimenting with different ways to compensateI tried a few Reutz type mods with some success, but after coming across @Chuck D. Bones ' excellent bass mod for the Rat/Expandora I realised that by omitting the boost section of the Parentheses Mini I could hack it neatly into the PCB
The mod is highly effective in this context. The lower left control becomes a bass boost allowing you to easily to restore your tonal balance after blending in the octave
Substitutions
Boost = C1KR29 = 22R
C23 = 47uF
R27 empty
R28 empty
R30 empty
R31 empty
R32 empty
R101 empty
C21 empty
C22 empty
Q6 empty
Jumpers
Jumper R21 to R29 - this can be achieved by jumping the cathode of C13 to the empty C22 exit padJumper Boost Out to ground - to connect the middle Boost wiper to ground
Here's what the jumper from C13 to C22 looks like:
You'll have to excuse my PCB looking rough - it's been through a lot
And here's my build, you can see the jumper from boost out to ground:
I put the LED on the right hand side of the footswitch to keep the wiring neat
Notes and observations
- Bass control on 0 is the stock position. The way to use this is to blend the octave in, then balance out your sound by gradually bringing up the bass. I find this is usually somewhere between 9 and 11 o'clock.
- The compensation cap in C12 has a meaningful effect on the character of the midrange. I've tried 33pF and 30pF so far, with 30pF being the brighter and more aggressive of the two. I think 33pF is more appropriate for this circuit, but for regular Rats I prefer 30pF.
- I think raising the corner frequency of the bass control will improve its function since the aim here is to compensate for the extra treble rather than to add more bass. I plan to experiment with this
- In lieu of a dedicated boost stage I am running it at 18v. This gives plenty of clean headroom for smashing the front of an amp. It hasn't exploded so far
- I used Tantalum caps because I have a bag of them to get rid of and it seemed like fun. I am getting more hiss than I would like so I will change them (not fun)
