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Boss MT-2 Twilight
Keeley Mod


The Boss MT-2 TZ mod was Keeley Electronics’ heaviest, most powerful, hard hitting modified pedal. The many modifications Robert created made this pedal a hi-fi monster. Every component changed or added was of the highest quality. We kept this mod exactly to the classic Keeley specs. Metal film resistors are used for a low noise floor, something absolutely required for a high gain pedal. You will notice your new modified MT-2 has a lower noise level than the stock pedal! Metal film and poly capacitors are used in the coupling sections to provide the true mid-range and high frequency transparency your guitar tone needs while increasing the bass response of the pedal. It goes without saying that the note definition has been improved. The final result is a pedal that provides more gain and volume while losing no note definition.

What you get with the Keeley MT-2 Twilight Zone Mod!

1. Better bass response along with true mid range and high frequency transparency
2. Keeley's heaviest, most powerful, hard hitting modded pedal!
3. Three-way toggle switch for 3 different distortions (stock, Triple Diode, Ultra Tube)
4. All of these mods give you the perfect pedal for that Mesa Triple Rectifier Crunch!

There are three modes of operation.

• SWITCH LEFT -- This is the “stock” MT-2 sound. You will notice however that the pedal has more presence, more powerful and true sounding midrange, and a tighter bass response.

• SWITCH RIGHT -- This is the Triple Diode Mode--our favorite. The Triple Diode Mode gives you the natural tube sound that makes that to-die-for molten guitar sound. It’s sick, fat, and has way more muscle than the stock MT-2 mode.

• SWITCH CENTER -- This is the Ultra Tube Mode. Beware! You will blow speakers with this mode! No, we’re serious! You must be aware that in this mode, the MT-2 mod has a super powerful output. This mode should be used with a 4X12 cabinet that can handle the power and ultra low bass this pedal can deliver.

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

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

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