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  • Guitar DIY

  • Adding a Bass Cut Pot to Ibanez RG style guitar

Hey guys so this is just some info regarding a pretty usefull mod that I added after experimenting a lot with different value components, ways to wire a guitar (50's wiring, vs modern vs how the tone cap is wired i.e. between vol and tone, grounded to tone pot different lugs etc.) and the concept comes from how EQ is used if I had to choose something, that is reductive EQ (probably not the correct word but makes sense to me).

I find when I want my tone to be brighter for instance, it is better to lower bass and mid frequencies than to boost treble and presence.

Some amps have massive low end compared to others especially if you use the amp as a pedal platform (or that's my experience at least).

The bass cut mod is probably one of the most usefull mods I have ever added, and I feel should be added to every guitar as standard.

I included a schematic, but if it is unclear please DM me and I'll try and help. Just note that the added pot is not grounded.

You can play around with the cap values, I dont go that aggressive with a 0.0047uF. More bass cut you can try 0.0033uF and less cut go to 0.0068uF.

Maybe do the alligator clip test before making anything permanent. At the bottom I see the pic is cut off, but that is a push pull tone pot and the 6 pin outs you will find once the pot is installed. So that is just how switch will be wired to the 5 way selector to split the coils. If you don't have this just ignore the switch wiring. I opted for a treble bleed that uses a 1 nF cap with a 150k resistor in series wired to the volume pot as shown. I used a 680pF cap before this, sometimes I prefer the 680pF sometimes the 1nF......still can't decide 🙂

Really is a worthwhile mod to try.

  • V8 likes this.

The -3db point for a first order high pass filter is calculated as f=1/2πRC. So at 500kΩ and 0.0047µF, the 3dB point is at about 68Hz while the low E string is about 82Hz. Effectively there is no bass cut because the knee of the filter is below the lowest string note. Rotating the pot to 250kHz, the- 3dB point is then at 135Hz which is about midway between the A string (110Hz) and the D string (147Hz). At 125k, the -3dB point is at 271k which is between the B and top E strings, so most frequencies will be cut.
Using a 0.0068µF might give you a better range on the pot with the corresponding -3dB points for 500k, 250k and 125k at 47Hz, 94Hz and 187Hz.

  • V8 likes this.

Thanks for that, I did try to incorporate a resistor into the Bass cut pot in order to retain the mid and upper mid freq. I'm sure you are correct regarding the point at which freq will be cut, I'm quite surprised though as it sounds like the bass and some lower low mid gets cut but not as wide as you are describing.

However I don't really have in-depth knowledge about RC circuits or software to model the response etc. so I kinda just went by ear and what I could find as suitable ranges for the specific circuits as starting point and went from there.

The resistor value I tried with the bass pot (i cant remember if I wired it series or parallel - probably in parallel) did something else with the preservation of the mid freq. so I either wired it incorrectly or wrong value. I tried what I had and then opted to just leave it at what sounded the best.

I will def try the 0.0068uF in the guitar as you suggest and see what thats sounds like. I also don't turn the pot all the way down ever so that would make more sense to switch it out for a 0.0068uF.

Thanks a lot. Do you have any threads about stuff like this or education regarding high and low pass specific to guitars, as I searched but was mostly theory of RC networks vs guitar mods on the other end with no explanation on the other end.

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