Feeling a bit lost with all the different Eurorack Buses? Here is a list and a summary of the various versions available.
Overview
The Eurorack Buses share in common:
- Standard shrouded 16-pin Eurorack connectors,
- Tight footprints (less impedance between connectors),
- Inputs through screw terminals for maximum adaptability,
- LEDs for polarity check,
- Very detailed silkscreens,
- High quality, 1.6mm thick FR4 PCBs.
3 different form factors are available: Small (10x5cm), Medium (20x5cm) and Large (25×5 or 25x6cm).
If you prefer the DIY way, some buses are available as “PCB only”. Most are using Through Hole components only, unless noted.
And if you just want a plug-and-play solution, some buses are also available as “Fully Assembled and Tested”.
An On-board regulator, if present, generates the +5V rail if your Power Supply doesn’t provide it already. If you prefer to use the +5V rail coming from your PSU instead, then either do not install the on-board regulator and its associated components, or choose a board that does not host an on-board regulator.
In any case, avoid to connect the +5V output of your PSU into a Bus equipped with an on-board +5V regulator.
| Model | Version | Connectors | Size (cm) | On-board +5V | DIY |
|---|---|---|---|---|---|
| Compact | 1.1c | 10 | 10×5 | No | Yes (with SMD) |
| 14 DIY | 1.1 | 14 + 5x1U + 2xAS | 20×5 | Yes | Yes |
| 14 Plug-andPlay | 1.1 | 14 | 20×5 | No | No |
| 18 | 1.0b | 18 | 20×5 | Yes | Yes |
| 26 | 1.0b | 26 | 25×5 | Yes | Yes |
| 28 | 1.0 | 28 | 25×6 | Yes | No |
In details
Eurorack Compact Power Bus
The Compact Power Bus is the smallest one (10x5cm), perfect for small skiffs, prototyping, case extensions etc. It hosts probably the most connectors for its size in the world (probably ;))
This bus has no on-board regulator so you must bring it from the PSU or plug an additional +5V regulator on a card.
The protection resistors for the LEDs are located on the bottom side and are SMD. But don’t panic, these are 1206 (0805 also fit), so anyone can solder them. Besides, it can be an easy first step in SMD world.
Bus 14 – DIY
The DIY version of the Bus 14 has a series of very special additional connectors: 2 x Analogue Systems sockets and 5 x 1U 3-pin connectors.
Other wise it features, as its name implies, 14 16-pin Eurorack connectors, and can host its own on-board +5V regulator.
No SMD. Perfect for small, diversified systems, and, of course, DIY.
Bus 14 – Plug-and-Play
This version of the Bus 14 is only available in Pre-built form. It has 14 x 16-pin Eurorack power connectors (no 1U and no AS connectors) and also, it has no on-board +5V regulator.
Bus 18
The Bus 18 the younger sibling of the Bus 14, but this time, no exotic connector! Just 18 Eurorack connectors for your middle-size case.
It will also provide the +5V with its on-board regulator.
No SMD again and ok for DIY. But beware that’s already a lot of solder joints!
Bus 26
Now we enter the category of the biggest buses. The Bus 26 has… 26 Eurorack connectors! For a length of 25cm only.
Okay for DIY with Through Hole components only (but that’s a lot of solder joints!). This sturdy bus can power big cases! Yet, its shortness still allows low impedance between the connectors. (To achieve the lowest impedance possible, use the shortest ribbon cables available).
Bus 28
The Bus 28 is the biggest of all. With its 28 Eurorack connectors, you can supply a really big case! As always, the key is the short distance between each connector, which should improve the impedance between each of them. (To keep the impedance as low as possible, use the shortest ribbon cables available).