The Mojo Hand FX Nebula IV is a phaser pedal from Mojo Hand FX, built closely on the classic MXR Phase 90 design and adding a level knob the original never had. Premier Guitar reviewed it in 2012, listing a street price of $159, and found it good for subtle-to-radical phase effects1.
What it is and what it does
The Nebula IV is a four-stage phaser in the Phase 90 mold. Premier Guitar wrote that it "clearly derives a lot of inspiration from the classic MXR Phase 90 design," and the reviewer's verdict was that it is beautifully built and "super dimensional," good for subtle-to-radical phase effects1. Like the Phase 90, it shares a rate control and an orange exterior, though the reviewer noted the Nebula IV "arguably trumps the MXR in the visual department" with its silkscreened astronaut graphic1.
Controls
| Control | What it does |
|---|---|
| Rate | Sets the speed of the phase oscillation1 |
| Level | Combats the level drop suffered by early MXR Phase 90s1 |
Circuit and build
Premier Guitar's review dug into the circuit and found the Nebula IV shares the same component configuration as an original bud-box Phase 90: 28 resistors, five matched JFET transistors, six op-amp stages, two diodes, and 10 capacitors1. The modern difference is in the op-amps: "Instead of six TI 741 op-amps taking up space, there are three TI dual-stage TL072s mounted in sockets"1, which makes swapping chips straightforward for anyone who likes to tinker.
Other hardware includes a true-bypass switch, a Boss-style power jack, and an LED indicator1.
"Mojo Hand is among the newer builders successfully using modern technology to channel the feel, spirit, and sound of old."
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Questions
Is the Mojo Hand Nebula IV true bypass?
Yes. Premier Guitar's 2012 review notes that the Nebula IV includes a true-bypass switch, along with a Boss-style power jack and an LED indicator. True bypass means the pedal's circuit is taken out of the signal path entirely when it is switched off, so your clean tone passes through unchanged.
What is the Nebula IV based on?
The Nebula IV is based on the classic MXR Phase 90 design. Premier Guitar wrote that it clearly derives a lot of inspiration from the Phase 90, and the review found it shares the same component configuration as an original bud-box Phase 90, with three TL072 op-amps in place of the original's six 741s.
What does the level knob do on the Nebula IV?
The level knob makes up for the volume drop that early MXR Phase 90s suffered from. It lets you match or boost the pedal's output level against your clean signal, so switching the phaser on does not make your tone quieter.
What power jack does the Nebula IV use?
The Nebula IV uses a Boss-style power jack, the 2.1mm center-negative connector that most pedalboard power supplies provide. Premier Guitar's review also notes the pedal has a true-bypass switch and an LED indicator.
Sources (1)
- Mojo Hand Nebula IV Phaser Pedal Review, Premier Guitar, 2012-05-11
