The JAM Pedals "Arachnid" Harmonious Monk is a hand-painted, one-of-a-kind custom artwork version of the Harmonious Monk mk.2, the harmonic and amplitude tremolo pedal that JAM Pedals builds with That Pedal Show. Every limited artwork pedal is painted by hand, so each Arachnid differs in detail from the photos on the maker's page1.
Under the paint it is the same pedal as the standard Harmonious Monk: JAM Pedals describes its custom artwork versions as "same sound, different artwork"2. That means an all-analog, true-bypass tremolo with two voices, tap tempo, a ramp function, a Legacy mode and a kill-dry CHOP effect, all covered below.
What it does to your sound
The Harmonious Monk carries two tremolo voices. Harmonic mode creates rich, phase-like movement, the kind of tremolo where the tonal balance shifts rather than the volume simply dipping. Amplitude mode provides traditional volume modulation, the classic rise and fall players know from amplifier tremolo1.
Because both voices live in one pedal, you can move between a subtle, swirling harmonic texture and a straight volume pulse without changing pedals. The waveform selection adds further range, including a square wave that, pushed to full depth, becomes the CHOP effect described below1.
The controls
The top-panel knobs cover the four core settings, and JAM Pedals lists input and output as in phase1.
| Control | What it does |
|---|---|
| Depth | Sets the intensity of the tremolo |
| Speed | Sets the rate |
| Level | Controls the output level |
| Mix | Blends dry and wet signals |
Inside the pedal there are four more adjustments:
- Treble trimmer: shapes the treble of the effected signal1
- Midrange trimmer: shapes the midrange of the effected signal1
- Bass trimmer: shapes the bass of the effected signal1
- Wet-path input gain trimmer: a fourth trimmer that adjusts the input gain of the wet path1
The three EQ trimmers let you voice the tremolo to your amp and guitar, while the input gain trimmer sets how hard the wet path is driven1.
Tap & Ramp mode and Legacy mode
The pedal has two footswitches. In the default Tap & Ramp mode, tapping the right footswitch sets the tempo. Holding it ramps from the current rate to a second speed: while holding the switch, the Speed knob defines the destination and the Depth knob defines the travel time. That gives you a foot-controlled swell or acceleration between two tremolo rates1.
Legacy mode is entered by holding both footswitches until the LEDs blink. In Legacy mode the right footswitch toggles speed multiplication, choosing x2 or x1.5 by holding the TAP switch until two or three confirmation blinks appear1.
The pedal draws up to 145 mA at 9V DC, center negative, and JAM Pedals recommends an isolated supply. That current draw is well above what a battery or a small daisy chain can comfortably deliver, so plan on a proper power brick1.
The kill-dry CHOP effect
For the hard, gated chop sound: select Amplitude mode with the square wave, then turn Depth fully clockwise. This activates the kill-dry CHOP function, which alternates between sound and silence rather than modulating volume smoothly. It is the most extreme setting on the pedal and works well for rhythmic, stuttering parts1.
History and artwork versions
The Arachnid is a hand-painted custom artwork version of the Harmonious Monk, with the same sound and different artwork12.
JAM Pedals sells the Harmonious Monk mk.2 as several custom artwork versions alongside the Arachnid, all with the same sound and different paint1:
- "Beast" Harmonious Monk
- "Cactus Totem" Harmonious Monk
- "Achenbach" Harmonious Monk mk.2
- "Relic" Harmonious Monk mk.2
The Achenbach version is sold out2, and the Relic version is listed as sold out as well4. Because each artwork pedal is painted by hand, the Arachnid you receive will differ in detail from the photos shown, and no two are identical1.
Buying and returns
The Arachnid is listed at £334.00 GBP on JAM Pedals' own page1. UK orders are shipped DDP with 20% UK VAT and all duties included, so there are no extra charges on delivery, and shipping is free1. JAM Pedals also offers a 30-day money-back guarantee, with a refund no questions asked if you are not satisfied within 30 days of receiving the product1.
For more on the effect type generally, see the tremolo pedals page.
Videos
That Pedal Show
Pete Thorn
JAM pedals
Questions
Does the Arachnid Harmonious Monk sound different from the standard Harmonious Monk?
No. JAM Pedals describes its custom artwork versions, including the Arachnid, as the same sound with different artwork. The Arachnid is a one-of-a-kind hand-painted Harmonious Monk, so the circuit, controls and features are identical to the standard version.
Is the JAM Harmonious Monk true bypass?
Yes. JAM Pedals lists the Arachnid Harmonious Monk as true bypass, so with the pedal disengaged your signal passes through without buffering. Input and output are in phase.
What is the difference between harmonic and amplitude tremolo?
Amplitude mode is traditional tremolo: the volume of the signal rises and falls. Harmonic mode instead creates rich, phase-like movement, the style of tremolo associated with older amplifier circuits. The Harmonious Monk gives you both voices in one pedal.
How do you get the chop effect on the Harmonious Monk?
Select Amplitude mode with the square wave, then turn the Depth knob fully clockwise. This activates the kill-dry CHOP function, which alternates between sound and silence for a hard, rhythmic gating effect.
Is the Harmonious Monk analog or digital?
The circuit is all analog, according to JAM Pedals' product page. It draws up to 145 mA from a 9V DC center-negative supply, and JAM recommends an isolated supply.
What does the internal Treble trimmer do on the Harmonious Monk?
The internal Treble trimmer shapes the high frequencies of the effected signal. There are also internal Midrange and Bass trimmers for the wet signal, plus a fourth trimmer that adjusts the wet-path input gain.
Sources (4)
- "Arachnid" Harmonious Monk, JAM Pedals (jampedals.com)
- "Cactus Totem" Harmonious Monk, JAM Pedals (jampedals.com)
- JAM Pedals Harmonious Monk mk.2 Review, Premier Guitar, 2024-01-21
- Harmonious Monk Bass Limited Artwork, www.jampedals.com
