This pedal mirrors the Dumble amplifiers in many ways. The Holygrail Overdrive is a simple, somewhat homely looking pedal, and its knobs and jacks appear to have been labeled with a garden variety label-maker. The controls are Drive, Accent, Tone, and Volume, and features a Comp/Open voicing switch, just like the Dumble Overdrive Special Jazz/ Rock switch.

Absolutely next level when it comes to sweet, touch-sensitive overdrive and impeccably clean, transparent boost. The Dumble-like tones that come out of these little stompboxes is unreal! The controls are extremely responsive and allow for a massive spectrum of tonal options, all of which are completely usable.

GTOWN amps

Review by The Gear Page

Review by Stompbox Steals

Demo by Mike Hermans

Demo by John-F. Klaver

Product Page

Holygrail OD 1

This pedal mirrors the Dumble amplifiers in many ways. The Holygrail Overdrive is a simple, 
somewhat homely looking pedal, and its knobs and jacks appear to have been labeled 
with a garden variety label-maker. The controls are Drive, Accent, Tone, and Volume, 
and features a Round/Open/Sharp voicing switch. HiCut switch for using the pedal 
in front of bright sounding amps.

Absolutely next level when it comes to sweet, touch-sensitive overdrive and impeccably 
clean, transparent boost. The Dumble-like tones that come out of these little stompboxes 
is unreal! The controls are extremely responsive and allow for a massive spectrum of 
tonal options, all of which are completely usable.

Demo by SRGuitar

Demo by  魔法の箱研究所 - Stompbox Review Channel -

Review by guitar pedal X

Review by delicious audio

Holygrail OD v2

his is Dr335’s little brother. Where the Dr335 is a two channel drive, this is a single channel.

Built along the lines of the classic Dumble amps. The goal was to achieve the sound of Mr335, so it’s a very Larry Carlton/Robben Ford sounding pedal.

The sound can be described as transparent, natural and woody going from a clean boost to mid gain. Three clipping mod switch Hard/Open/Soft which gives a nice versatility of sound options depending on the amp/guitar-combination being used and your playing style.

Demo by  John-F. Klaver

Demo by Sam Vilo

Dumble style sounding double channel overdrive. Covers as many as from clean booster till roaring high gain.

Holygrail DualDrive channel 1 is our Holygrail Overdrive. Channel 2 is our 335 overdrive. Channels connected series as follow:
Input->CH2 -> CH1->Output.

Each channel have a three way clipping switch allows to choose three different clipping modes. Each channel have a different voicing which in conjunction with clipping mod options provides a lot of sounding combinations.

Official Product Video

Demo by intheblues

Holygrail DualDrive

Built along the lines of the classic Dumble amps.
The goal was to achieve the sound of Mr335, so it’s a very Larry Carlton/Robben Ford sounding pedal.
The sound can be descriped as transparent, natural and woody going from a clean boost to mid gain.

Four controls are available on each channel: Drive/Tone/Edge/Volume. Each channel is equipped with a three clipping mod switch Hard/Open/Soft which gives a nice versatility of sound options depending on the amp/guitar-combination being used and your playing style.

DR335