There are XLRs with crimp connections, available from the likes of Neutrik, but they’re arguably better suited to large‑scale factory manufacturing techniques than DIY.
I saw some crimped XLR connectors online, and I wondered what the advantages are of soldered connections over crimped ones. I’ve seen crimping used in lots of other industries and other audio connectors like EDAC looms, terminals on passive loudspeakers and RJ45 connectors. I’ve seen solderless jacks used for guitar pedalboards. Having soldered a few DB25 looms, I can see why crimping might be more convenient! But I’ve very rarely encountered XLRs that are constructed this way, or premade cables for that matter. Is there an advantage of using soldered joints (or a disadvantage with crimped ones)? If so, does that apply to all signals, or perhaps only to quieter ones such as mic level, where XLRs are routinely used?
Ian Gorant
SOS Technical Editor Hugh Robjohns replies: First off, I don’t believe signal level is relevant here: a good connection is a good connection, and that’s all that’s required whether we’re talking mic level or line level.
I’ve never seen a crimp‑style jack connector, but Neutrik currently offer a crimp version of the XLR and, in the past, I recall that they also offered an IDC version (more on this type below) for a while too. However, I’ve never knowingly used XLR cables made with either type of connection; they’ve all been standard ‘solder bucket’ types.
Soldering wires into XLRs, or jack plugs for that matter, is a familiar, well‑established, and relatively easy‑to‑learn technique that uses commonly available and low‑cost tools (ie. a soldering iron and solder). Importantly, that methodology has decades of proven reliability in the field, and can be repaired easily in the field with standard tools and skills.
The tools required for conventional soldered connections are readily available and needn’t cost the Earth...
The two common industrial alternatives to soldering are insulation displacement connections (IDC) and crimping. Both techniques essentially ‘cold weld’ the wire to the contact to make a gas‑tight connection, which is necessary to impede corrosion of the joint. Both can theoretically be used in factories or in the field. Crimping and IDC are designed to be faster to implement than soldering, and crimping in particular can be very beneficial in very high‑density connectors. However, in both cases, the connector has to be designed appropriately for crimping or IDC, and special (meaning expensive) dedicated assembly tools are normally required.
For IDC, an axial tool (working at 90 degrees to the wire) is usually required to force an insulated wire between the terminal connector blades, although ‘no‑tool’ IDC connectors are increasingly common (where a bladed cover is tightened down forcing the wires into the contact terminals). IDC systems have the advantage that they don’t require the wire insulation to be removed prior to insertion as the blade cuts straight through it and into the wire itself, speeding up the assembly process. However, IDC only works well with solid‑cored wire, and while that’s fine for installed cabling systems, it’s not so good where cables need to be flexible and robust as that usually requires multi‑stranded wires. Also, the gas‑tight connection area between the wire and blades is inherently very small indeed, potentially affecting reliability.
In the case of crimping, a bespoke radial tool (working around the wire) is required to crimp the contact terminal onto the (insulation‑stripped) wire, which means the connector has to be designed to facilitate that technique. Unfortunately, the multi‑pinned XLR doesn’t naturally lend itself to that approach, but a common solution for complex connectors like this is to crimp the contacts onto the wires away from the connector, and then insert them all into the connector body afterwards. Key benefits of crimping include a much larger gas‑tight joint area than IDC, and the technique works reliably with stranded wire.
Dedicated crimping tools aren’t cheap and they’re not something you’re likely to find in most audio repair shops, let alone the field.
Crimping suits factory manufacturing very well, with cables being prepared at one station, connectors crimped on at another, and then insertion into the connector body at a third, followed by testing. However, a bespoke crimping tool is generally required, designed for the specific contact terminal design. And inserting the contacts into the connector body often requires another special tool. In most cases, a third dedicated tool is also required to release the contacts when necessary for repair/replacement. Dedicated crimping tools aren’t cheap — that for the Neutrik Crimp‑XLR costs around £400 (about $500), for example — and they’re not something you’re likely to find in most audio repair shops, let alone the field, so repairing crimped connectors can be a serious problem.
For a manufacturer producing a very large number of cables, crimping can potentially save enough time and money to justify investing in the specialist equipment, especially for complex, high‑density connectors. But, in the case of standard XLRs, which are easy to solder, it seems few think there is a cost‑effective benefit. There are also significant disadvantages including the initial bespoke equipment cost and the difficulty of repair because the relevant tools are likely to be unavailable outside of the factory.