The Nocturne Atomic Brain 301 is an analog preamp booster for guitar, pedal steel, keys and bass, built by The Nocturne Brain. Its circuit is a much improved replica of the vintage Japanese 1970s preamp from the Roland RE-301 Tape Delay machine, better known as the Space Echo: instead of hauling a tape echo around for its preamp section, you get that part alone in a compact pedal with a single stomp switch, finished in pastel rose with a bold black faceplate1.
The maker describes the result as "a very reactive, and tube like dynamic enhancement" in which notes bloom and chords ring out while the guitar tone stays up front and pure. It is a preamp pedal, not a drive box: the gain on tap is preamp gain, and the boost mode works on impedance rather than clipping1.
Where the circuit comes from
The RE-301 Space Echo was a 1970s Roland tape delay unit whose preamp section players came to prize on its own. The Nocturne Brain's take starts there: the maker says the original RE-301 preamp was actually much quieter, with greater headroom than its predecessor the RE-201, which used random non-spec carbon film resistors and transistors2.
The replica is not a straight copy. The maker lists three deliberate changes12:
- Improved input impedance
- Extended gain range
- A Bass Cut the original RE-301 did not have2
The full-size Atomic Brain version also moves from the original Toshiba linear opamp to a more modern single opamp in an 8DIP package, which the maker says gives less noise, wider bandwidth and less distortion at higher saturation points. A NOS metal can chip is available as an upgrade for players who want the original part2.
The controls
The Atomic Brain 301 keeps its control set small: a global gain knob, a Bass Cut knob, two toggle switches and the ABBY stomp. Here is what each one does, as the maker describes it1.
| Control | What it does |
|---|---|
| Gain | Global gain control; with all toggles up and ABBY engaged, set just above unity gain it makes thin guitars fuller through the amp |
| Bass Cut | Trims low end; 7 o'clock gives a leaner, tighter modern flavor, 4 to 5 o'clock gives the vintage full low mids of the original character |
| Left toggle | High presence cut; takes a little gain in that frequency down a notch |
| Right toggle | Shifts the impedance; up feels louder but actually increases sensitivity to pick dynamics |
| ABBY stomp | Opens the preamp gain range wide for a solo boost |
The two toggles are where the pedal adapts to different rigs. The left toggle's presence cut is aimed at specific problems: it smooths top end overcoloring with Dynasonic and large bobbin single coil pickups, reduces piezo quack on acoustic instruments, and tames the brightening that comes from pedals with an always-on buffer, such as Boss and Ibanez/Maxon units1.
The right toggle is an impedance shift rather than a volume change. In the up mode it feels louder, but the maker says it is actually increasing sensitivity to pick dynamics. The maker points to three groups who benefit: players into master volume amps, piezo pickups that want a higher input impedance, and electric basses getting more growl1.
ABBY and the Bass Cut in detail
ABBY is the second mode, and the maker is specific about how it differs from a conventional boost. It is not cascading gain or doubled diode clipping like other drive boxes; it opens the preamp gain range wide, modifying the guitar's impedance response instead. The maker says ABBY makes everything about 35% more dynamic than the NORMAL mode level, and the more the normal channel gain is turned up, the more boost ABBY gives1.
"this dB boost mode isnt acting like other drive boxes that employ cascading gain or double up on diode clipping"
The Bass Cut exists for a practical problem: keeping a cranked small amp's speaker from farting out. At 7 o'clock the tone sweep gives a leaner, tighter modern flavor; at 4 to 5 o'clock you get the vintage full low mids of the original RE-301 character and color1.
Power, versions and ordering
All Nocturne Brain preamps operate at 9V and 12V. The maker prefers 9V, for more texture and saturation at maximum gain. Power comes in through a 9V DC center negative, Boss style plug, and no power supply is included, so you need your own1.
The Atomic Brain 301 is built per order with no returns. Average turnaround is 3 weeks, delivered via USPS Priority insured, or DHL insured internationally. The warranty covers electronic parts and labor for 1 year, shipping not included1.
Alongside this compact single-stomp version, the range includes the full-size Atomic Brain, a wider box the maker describes as being for "the big booted folk," which uses Switchcraft jacks with hardwire true bypass and, with the right toggle up, replaces the earlier Billy Brain with a bigger, more vintage blonde Fender Showman/Bassman attack2. A repro "old school handwired" version of the 301 is also available to order1. The maker's line also extends to pedals like the JR Barnyard Pre-War Hot Preamp V2. The Atomic Brain name and logo carry U.S. Trademark SN: 87678190, with logo artwork by Vince Ray1.
Questions
Is the Nocturne Atomic Brain 301 true bypass?
Yes. The Nocturne Brain states the Atomic Brain 301 is true bypass and built with hi-fidelity audio components. The full-size version of the pedal uses Switchcraft jacks with hardwire true bypass, so the signal passes straight through when the pedal is off.
What is the ABBY mode on the Atomic Brain 301?
ABBY is a second footswitch mode that opens the preamp's gain range wide for soloing. The maker says it makes everything about 35% more dynamic than the NORMAL mode level, and the more the normal channel gain is turned up, the more boost ABBY gives. It works by modifying the guitar's impedance response rather than cascading gain or doubling diode clipping.
Does the Atomic Brain 301 come with a power supply?
No. The Nocturne Brain lists the Atomic Brain 301 with no power supply included, so you need your own 9V DC supply with a center negative, Boss style plug. The pedal is built to order, with an average turnaround of three weeks.
Should the Atomic Brain 301 run at 9V or 12V?
It operates at both 9V and 12V. The maker prefers 9V, saying it gives more texture and saturation at maximum gain. Power connects through a 9V DC center negative, Boss style plug, and no supply is included in the box.
What does the Bass Cut do on the Atomic Brain 301?
The Bass Cut trims low end so a cranked small amp speaker does not fart out. Set back to 7 o'clock it gives a leaner, tighter modern flavor; at 4 to 5 o'clock you get the vintage full low mids of the original RE-301 character. It is a control the original RE-301 preamp never had.
How does the Atomic Brain 301 differ from the original RE-301 preamp?
It is a much improved replica of the vintage Japanese preamp from the Roland RE-301 Space Echo. The Nocturne Brain improved the input impedance, extended the gain range and added a Bass Cut the original did not have. The full-size version also moves to a modern single opamp in an 8DIP package for less noise and wider bandwidth.
Sources (2)
- ATOMIC BRAIN® 301 Analog preamp, The Nocturne Brain (thenocturnebrain.com)
- Atomic Brain™ full size hand wired version for the large footed, The Nocturne Brain
