This is why we use a recessed DC Power Connector on our pedals

Our DC Power Connectors are commonly used by numerous pedal makers worldwide, making them a standard choice. These connectors typically require a DC Power Plug with an outer diameter of Ø 5.1mm and an inner diameter of Ø 2.1mm. With an internal depth of 10mm, they easily accommodate any DC Power Plug with a barrel longer than 10mm. However, it’s important to note that the “BOSS standard” DC plugs have a shorter 10mm barrel. To ensure a reliable electrical connection, we have opted to solder these connectors on the main circuit board, recessed behind the 2mm thick enclosure wall. Hence, a DC Power Plug with a 12mm long barrel is necessary for good electrical connection.

Why do we mount the DC Power Connector recessed on the main board?

The main reason for mounting the DC Power Connector recessed on the main board is due to the design of Hammond enclosures. These enclosures have tapered walls with a thickness of 2mm. By recessing the DC Power Connectors behind the enclosure walls, the thickness of the walls adds up and prevents a 10mm short-barrel from fully entering the DC Power Connector.

There are multiple considerations behind this design decision. Firstly, avoiding the use of wires throughout the builds to connect potentiometers, switches, and other large components to the board is desired. While using wires allows for flexible assembly, it leads to a messy interior and increases the risk of future failures due to wire snaps. Therefore, a DC Power Connector that can be directly mounted on the enclosure wall and connected with wires to the board is not preferred.

Additionally, the limited space inside MINI’s pedals is a factor to consider. Directly mounting connectors on the enclosure wall would not leave enough room to fit such connectors in MINI’s. Moreover, the protrusions of the connectors outside the enclosure give an unattractive appearance. Although this may be overlooked in large-size pedals, it is not acceptable in MINI’s.

Furthermore, if the intention was to create square holes through CNC machining to allow the DC Power Connectors to pass through the enclosure instead of recessing them 2mm behind the enclosure wall, the pedal assembly would not be possible. This limitation highlights the necessity of the recessed mounting design for the DC Power Connectors.

We prioritize maintaining rigidity and achieving a strong and compact assembly for all the parts involved. To ensure this, certain large parts penetrate the enclosure through precisely positioned tight holes, allowing movement in only one direction within the 3D space, specifically from the bottom to the top face. Due to the presence of multiple tightly positioned holes, there is insufficient space between them to enable lateral movement for the passage of a DC Power Connector through the enclosure wall.

Conversely, we have decided against drilling large holes in front of the DC Power Connectors, as some other manufacturers do, solely to accommodate the plastic jacket of the plug through the enclosure wall. The presence of such large holes not only detracts from the aesthetic appeal by exposing the connector inside but also increases the risk of dust entering. We have made this decision based on the following reasons.

Our Hammond enclosures arrive pre-painted with an aesthetically pleasing rough black powder coating. After printing the white markings, we CNC-machine the enclosures. If we were to drill larger holes solely to accommodate the plug’s plastic jacket passing through the enclosure, it would expose the aluminum surface, potentially leading to electrical shortages. Unfortunately, we cannot apply a new coating to the inside of the drilled holes. Additionally, if we were to enlarge the holes further to accommodate a larger plastic isolation ring, they would appear even more unattractive, particularly on the MINI pedals.

The aluminum enclosure is electrically connected to the circuit’s ground and negative power polarity to provide electromagnetic shielding. To ensure safety and prevent potential shortages, we drill small-diameter holes in which we insert plastic rings. This design choice is made because the plugs carry the positive polarity on the outer surface of the barrel. The tight-fitting isolation rings not only prevent shortages but also contribute to the overall rigidity of the assembly.

This deliberate design approach serves a practical purpose. In the event of accidentally stepping on the plug, the strength of the enclosure provides protection to the internal connector. We believe this is an excellent design choice that combines functionality and aesthetics, as the smaller holes offer a visually pleasing appearance.

Is a 10mm short-barrel DC Power Plug completely unusable?

No, that’s not entirely true. In fact, a 10mm short-barrel DC Power Plug can be used effectively, especially when combined with a snug-fitting plastic isolation ring. This ring helps to secure the 10mm barrel plug in place most of the time, depending on the specific design of the barrel tip.

However, it’s important to note that due to the thickness of the enclosure, a short-barrel plug cannot be fully inserted onto the recessed DC Power Connector. As a result, the electric contact between the outer side of the barrel and the contact blade inside the connector may become fragile. This incomplete insertion can lead to a loose connection, causing interruptions in the powering of the pedal. Additionally, mechanical shocks can further dislodge the short-barrel plug, resulting in intermittent power loss.

Therefore, to ensure a reliable electrical connection inside the recessed DC Power Connector, a DC Power Plug with a 12mm long barrel is required.

How do we notify users on the requirement for DC Power Plugs with 12mm long barrel?

In product presentations, manuals, and technical specifications present in product pages, we do advise to power our pedals with center negative DC Power Plugs having Ø 5.1mm external diameter, Ø 2.1mm inner diameter, 12mm long barrel. Manuals also advise users on using only good filtered and regulated power supplies and highlight the need of keeping the DC power voltage within specified limits. Additionally, we have compiled a set of relevant technical information in the CompIQ 101 present in every compressor’s presentation page and as a blog post.

Where to get power leads with DC Power Plugs with a 12mm long barrel?

Some high-quality power sources such as those made by Voodoo Labs or Cioks already come with power leads having longer barrel plugs. There are many replacement options for DC power cables fitted with longer barrel DC Power Plug e.g., Voodoo Labs, Cioks, MXR, EBS, etc. eBay is a rich source for very cheap such leads – just look for the ones with a longer barrel. Tech and music shops near your location may offer such leads or separate plugs as well.

If you don’t want to purchase a new power cable you can trim 2 mm from the plastic jacket of a DC Power Plug with a 10mm short barrel.

Since the DC Power Plug’s isolation jacket is usually made from a rubbery plastic, it is very easy to trim a couple of millimeters out of it to expose a longer barrel. We recommend this simple adjustment which works just fine and it takes less than a minute to do it. This way, the 12mm long barrel passes through the 2mm thick enclosure wall and can be fully inserted into the recessed DC Power Connector.