My Cart


Boss BD-2 Phat
Keeley Mod


The Boss BD-2 has a pretty good tone to start with. The pedal you have now is the culmination of many ideas and modifications that Robert Keeley had made to the pedal over the years. Every component added is of the highest quality. The parts added will increase the warmth of the pedal and add a level satisfaction to your playing. Film capacitors are used in the tone section to provide the smoothest mid-range and high frequency components to your tone while increasing the bass response of the pedal.
This pedal has been modified to have slight asymmetrical clipping. This mod gives you 2nd order harmonic distortion. This has a very musical sound. At very high saturation levels it almost becomes an octave type of sound effect. Robert was never big on bass boosts in general so the switch on this pedal is mild in its effect on your tone. Moving the Phat switch up engages this tone. There is a slight bass increase felt when notes are played on the open E and A strings. Strum those strings while moving the switch back and forth to get an initial feel of the possibilities. It might be a good idea to turn the Phat switch off under loud situations if there is too much low end in your sound. The Phat mod also uses silver mica capacitors, which reduce the noise of the pedal to lower than stock levels. The only variation that has been made from the original Keeley BD-2 Phat was the use of audio grade electrolytic capacitors in the signal path. We felt that this lowered the noise floor further and improved the overall signal clarity with cleaner tones.

What you get with the Keeley BD-2 Phat Mod!

1. Better bass response along with true mid range and high frequency transparency 2. Silver mica capacitors added to reduce the noise of the pedal to lower than stock levels
2. Modified to have asymmetrical clipping, give a more tube like distortion
3. "Phat" switch to give you more bottom end, great for playing at home or smaller venues
4. All of these mods give you an extremely dynamic and transparent overdrive that can go from clean to rock and everywhere in between!

Recommended starting points: Try setting the Tone and Gain Control at about 10 O’clock and the Level at 12 O’clock noon. Most modern amps are a little bright sounding so this might sound really good for a starting point. For a crisp yet really smooth sound driving a tube amp, we like to set the Tone Control to 11 and then set the Gain to about 3 and Level control to about 2-3 O’clock. Stand back and enjoy! As you turn the Gain up you can approach a nice, refined fuzz face type of sound. Something that is very dynamic and sensitive to your playing technique. All you need to do to control the distortion is to adjust the volume control on your guitar!

All modifications are warranted for you, the original owner, for one year. If you have any problems at all please email Mammoth Electronics at If you are happy with this product, please let everyone know and tag us on Instagram and Facebook with #mammothelectronics. If you are not happy with this product for any reason at all, please let us know within 48 hours and we will refund your order. The entire Keeley and Mammoth team thanks you for your business. You’re keeping the good tones alive! If you like this product, there’s more where it came from, check out the rest of our products on

download button

Mod times are 3-5 business days from the day that your pedal(s) arrive. Please ship to the address below:

Mammoth Electronics
Attn: Mods Department
3203 Broce Dr
Norman, OK 73072

Join our Mailing List

Sign up to receive our informative email for specials and new products

My Cart

Subtotal: $0.00

Your cart is currently empty.