The Nocturne JR Barnyard Pre-War Hot Preamp V2 is a preamp pedal that puts the character of a 1930s and 1940s octal tube amp on your pedalboard. Nocturne, a family company from San Diego, California that hand-builds pedals, amps and preamps, designed it to emulate the preamp circuit of the Gibson EH-150 and EH-185, amps from the era when octal tubes were standard12.
Where a typical overdrive or distortion pedal is built around a clipping stage, the Barnyard is built as a class A discrete preamp. Delicious Audio describes the result as a "punchy honky almost reedy/flutey" late 1930s and 1940s swing sound when set clean, or, cranked, a "full on chess era wooly 50s chicago rhythm and blues" tone2.
A pre-war octal tube amp circuit in a FET preamp pedal
The Barnyard is Nocturne's take on the vintage octal tube amp circuit found in early Gibson and Dickerson amps2. The maker describes it as "more or less designed to emulate the preamp circuit of the Gibson EH-150 / EH-185"1. Octal tubes were the eight-pin glass bottles used in amplifiers before the smaller noval tubes took over, and the amps built around them have a character players associate with pre-war swing and early electric blues recordings.
The pedal reproduces that character with transistors rather than tubes. Delicious Audio describes the V2 as a FET based preamp using a hand selected, spec'd NOS Motorola transistor, with a mix of imported Soviet germanium and Fairchild silicon diodes at its core2. The maker's current product page describes the circuit as transistor (BJT, not FET) based, using the same mix of Soviet germanium and Fairchild silicon diodes1. The two descriptions of the active device disagree, but both agree the pedal is fully analog.
The build uses a short list of new-old-stock and name-brand parts:
- NOS Mial caps
- NOS Cornell Dubilier and Mullard, and/or Wima film caps
- Switchcraft jacks
- Hand wired leads from the circuit board2
The controls: blend, body depth and bright
The V2 keeps its control set small. The left knob is volume, and the right switch selects bass or guitar mode1. Two toggle switches shape the pedal for different instruments:
| Control | What it does |
|---|---|
| Left knob | Volume1 |
| Right switch | Bass or guitar mode1 |
| Body depth switch | Deep or flat, for a variety of guitars, mandolins, ukuleles, banjos and dreadnoughts12 |
| Bright switch | Adds brightness, also voiced for the same range of instruments12 |
| Blend control | Blends between the normal channel and a virtual, hotter mic channel2 |
The blend control is the heart of V2. The original Barnyard added a second channel that blends in the hotter mic channel of the EH-185, so the builder could dial in more texture; on the V2 that blend between the normal and the virtual mic channel is a knob, letting you add extra texture to taste12.
Power: 9V DC, no adapter included
The Barnyard runs on a standard Boss-style 9V DC adapter. No power supply is included with the pedal, and the maker specifies it requires an audio quality 9V DC power supply only12.
No adapter ships with the pedal. The maker calls for an audio quality 9V DC supply, so a cheap general-purpose wall wart is not what the circuit is specified for1.
Version 2: single stomp with a blend control
The V2 is a new single stomp version with a blend control between the normal and mic channel, plus a smaller, more compact size than the original2. On the earlier version, a second stomp switch on the left blended in the hotter mic channel of the EH-18521. The maker's current page lists the standard model as the single stomp version with the blend control, with the handwired original version available as an upgrade option1. The current product is covered on the Nocturne Brain JR BARNYARD page.
Questions
Is the Nocturne JR Barnyard Pre-War Hot Preamp V2 true bypass?
Yes. Both the maker's product page and Delicious Audio's writeup describe the pedal as true bypass, so with the effect switched off your signal passes through without buffering or coloring.
Does the Barnyard Pre-War Hot Preamp come with a power supply?
No. It runs on a standard Boss-style 9V DC adapter, but no power supply is included. The maker specifies that it requires an audio quality 9V DC power supply, so plan on supplying your own.
What does the blend control do on the Barnyard V2?
V2's blend control sits between the normal channel and a virtual, hotter mic channel modeled on the mic input of the Gibson EH-185. Blending the mic channel in lets you dial in extra texture and grit to taste, something the original version handled with a separate stomp switch.
What amps is the Barnyard Pre-War Hot Preamp circuit based on?
The circuit emulates the preamp of the Gibson EH-150 and EH-185, vintage 1930s and 1940s octal tube amps. Delicious Audio also notes the same octal tube circuit family appears in early Dickerson amps.
Is the Nocturne Barnyard preamp analog or digital?
It is analog. Delicious Audio describes the V2 as a FET based preamp using a hand selected NOS Motorola transistor, while the maker's current page describes the circuit as transistor (BJT) based with Soviet germanium and Fairchild silicon diodes.
Sources (2)
- JR BARNYARD® EH-150 /185 octal tube style Preamp, The Nocturne Brain
- Nocturne JR Barnyard Pre-War Hot Preamp V2, Delicious Audio, 2021-07-22
