The One Control Minimal Series Pedal Board Junction Box with BJF Buffer (OC-M-JBBUF) is a small utility box that combines two jobs in one enclosure: it routes your pedalboard wiring through a junction box, and it carries a switchable BJF Buffer circuit to stabilize your signal. One Control describes it as "a small box with two inputs and two outputs which is very simple, but makes a tremendous difference in your sound"1.
The input and output jacks sit on the top of the enclosure, so the box can sit on or under a board without wasting pedalboard space1. It weighs 220g and measures 94D x 46W x 40H mm1. One Control's product page lists it as sold out, with a regular price of $69.99 USD and $87.99 USD shown alongside it1.
What the BJF Buffer does
A buffer is a small amplifier circuit placed in the signal chain to preserve high-end and overall tone across long cable runs and rows of true bypass pedals. The BJF Buffer was designed by Björn Juhl of BJFe, and One Control says he built it "to help with the varied cable lengths and true bypass pedals in the signal chain"2. The same circuit appears across the One Control range: One Control states that "this exact buffer circuit" is installed in many of its switchers2, and it also appears in products like the One Control Minimal Series BJF Buffer, the One Control Minimal Series Black Loop Deluxe with BJF Buffer, the One Control Minimal Series Mosquito Blender Expressio with BJF Buffer, and the One Control LX Tuner with BJF Buffer234.
In this junction box, One Control says that "by turning on the BJF Buffer, you can stabilize your base tone to a warm and natural sound"1. The buffer runs at a precise unity gain setting of 1, meaning it does not boost or cut the signal level, it only conditions it1. With the buffer on, the input impedance is 500kΩ and the output impedance is 60Ω1.
Controls and how the routing works
The box has two switches and one power jack:
| Control | What it does |
|---|---|
| BUFFER/PASSIVE switch | Turns the buffer on or off. In PASSIVE mode the buffer is off and no power is needed1 |
| POLARITY/REVERSE switch | Inverts the phase between the BUFFER IN and BUFFER OUT jacks. Only works when the Buffer/Passive switch is on the BUFFER side1 |
| 9V IN | Connects the power adapter. The center LED lights up when power is connected successfully1 |
The routing depends on the buffer setting. When the buffer is off, both the A and B terminals can be connected from any direction you like, so the box behaves as a flexible passive junction point. When the buffer is on, the A side always enters from BUFFER IN and exits from BUFFER OUT, giving the active circuit a fixed direction1.
The polarity switch is worth noting for players running two amps or stereo setups where phase relationships matter. A phase inversion between the buffered input and output can correct cancellation problems, and One Control uses the same idea on its Mosquito Blender Expressio, where the POLARITY switch inverts the signal polarity and One Control advises setting it "to the one closer to the required tone while listening"4.
Power
The box runs on a 9V DC power supply with a standard center negative (center minus) 2.1mm barrel plug, and it draws only 3mA1. That is a very light load, small enough that it shares easily with other pedals on a typical isolated supply. An LED at the 9V input confirms the connection is good1.
Power is only needed when the buffer is on. In PASSIVE mode the box works with no power connection at all, so it can serve as a plain passive junction box on a board with no spare power outlets1.
Where it sits in the Minimal Series
The box belongs to One Control's Minimal Series, which the maker describes as offering "many useful tools for modern musicians who have increasingly complex pedalboards"5. The series includes the passive Pedal Board Junction Box 4M, a through box with an effects loop for time based effects processors5, and the BJF Buffer as a standalone buffer pedal2. The junction box with BJF Buffer sits between the two: it is the junction box with the active circuit added and made switchable.
Other One Control products carry the same buffer in different roles. The Black Loop Deluxe with BJF Buffer is a two-loop switcher whose input buffer can be switched on or off, letting it operate as either a true bypass or buffered device3. The One Control BJF Buffer Split is a utility box built around the buffer with splitting duties6. Compared with those, the junction box with BJF Buffer is the simplest of the three: no loops, no blending, just routing plus a switchable buffer and a phase flip.
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Questions
What does the Buffer/Passive switch do on the One Control junction box?
It turns the built-in BJF Buffer on or off. In PASSIVE mode the buffer is switched out and the box needs no power at all, so it works as a plain passive junction box. With the switch on the BUFFER side, the signal passes through the active BJF Buffer circuit.
Does the One Control junction box need power?
Only when the buffer is on. It runs on a 9V DC power supply with a standard center negative 2.1mm barrel plug and draws just 3mA. In PASSIVE mode no power connection is needed. An LED at the 9V input lights up when power is connected successfully.
What does the polarity switch do?
It inverts the phase between the BUFFER IN and BUFFER OUT jacks. It only works when the Buffer/Passive switch is set to the BUFFER side, so it is a phase flip for the active signal path rather than the passive one.
Who designed the BJF Buffer?
Björn Juhl of BJFe designed the BJF Buffer. One Control says he created it to deal with the varied cable lengths and true bypass pedals found in a modern signal chain, and the same circuit is installed in many One Control switchers.
Is the One Control Minimal Series junction box with BJF Buffer still available?
One Control's product page lists it as sold out. The page shows a regular price of $69.99 USD with $87.99 USD shown alongside it, but as of late October 2026 the unit is not in stock at the maker's own store.
Sources (6)
- Minimal Series Pedal Board Junction Box with BJF Buffer (OC-M-JBBUF), One Control USA
- Minimal Series BJF Buffer (OC-M-BUF), One Control USA
- Minimal Series Black Loop Deluxe with BJF Buffer (OC-M-BLDLX), One Control USA
- Minimal Series Mosquito Blender Expressio with BJF Buffer (OC-M-MBEXP), One Control USA
- Minimal Series Pedal Board Junction Box 4M (OC-M-JB4M), One Control USA
- Minimal Series BJF Buffer Split (OC-M-BJBUF), One Control USA
