Ashton Research Tetrapatch

The Tetrapatch TRP8 and TFP8 both feature the same complement of sockets, but arranged differently to suit rackmounting and desktop use cases.

Network cables don’t have to carry digital traffic. As Ashton Research’s debut range capably demonstrates, they can also work well in the analogue domain.

The RJ45 connector and associated twisted‑pair cable have long been ubiquitous in computer networking applications. This, in turn, has made them much cheaper to buy than standard multicore audio cables with the same number of cores. Consequently, there have been quite a few attempts to repurpose them for analogue and digital audio, perhaps the best‑known to SOS readers being the Cranborne Audio CAST system. In principle, the advantages are obvious: up to four channels of balanced analogue or AES3 digital audio can be carried on a cheap, compact and proven physical conduit of practically any length. In practice, different manufacturers have introduced different, incompatible conventions for mapping the channels onto the wires, which has probably held back its adoption in these applications.

The Audio Engineering Society sought to smooth the path in 2019 with the publication of the AES72 standard, but this perhaps hasn’t helped as much as you might expect. It doesn’t mandate the use of any particular pinout, instead merely noting and naming the different pinouts that are already being used. Thus, although there are already some ‘AES72 compliant’ products on the market, they aren’t necessarily compatible with each other.

The latest range of AES72 devices comes from a new company called Ashton Research. Ashton’s initial product portfolio comprises three passive boxes that pass audio between RJ45 and balanced quarter‑inch jacks, plus a rack tray and mounting bracket. All use the 1M pinout specified in AES72 and also employed by the likes of Link SRL, Wysicom and Sound Tools, but not for example by Neutrik in their AES72 stagebox.

Tet A Tet

The TFP8 and TRP8 (shown here) are functionally identical, and differ only in terms of physical layout.The TFP8 and TRP8 are functionally identical, and differ only in terms of physical layout. Both feature two RJ45 connectors, each with an associated bank of four quarter‑inch jack sockets. On the TFP8, all of this I/O is on the front panel. The TRP8, by contrast, has the RJ45s on the front and the jacks on the top, to suit different mounting contexts. Finally, the TP3F is described as a “four‑point patchbay slice”. On the rear, you’ll find two RJ45s and four balanced jacks. On the front are eight more jacks, providing break‑in and break‑out paths.

All can be mounted on the HF100 rack tray, which can accommodate four TFP8s or six TP3Fs in a 1U space. It could also mount up to six TRP8s, as long as you leave enough space above them for cables. A neat alternative for small installations is the HF101, which is effectively a rack ear that can mount a single Tetrapatch unit to a rack rail.

Ashton Research supplied one of each product for review, along with a couple of Cat7 (Class F) cables. Functionally, there’s nothing to stop you using the more familiar and cheaper Cat5e or Cat6 instead, but Cat7 has better noise rejection and crosstalk specs thanks to its superior shielding. The units themselves seem to be made of ABS or a similar plastic, and feel very tough despite being lightweight. And lightweight they are; although in theory you could use the TRP8 freestanding on a desktop, in practice it would be pulled around everywhere by the weight of the cables, so you probably will want to anchor it to something. The units attach to rack trays and brackets using supplied Torx bolts.

The system is passive and transformerless, so every RJ45‑to‑jack connection works in both directions.

The system is passive and transformerless, so every RJ45‑to‑jack connection works in both directions. For example, you could employ all eight jack sockets on a TRP8 as inputs, to be fed from synths and samplers, and use two Ethernet cables to transport these to a TFP8 which would then disgorge them as outputs on its eight jacks; but the same rig could also be employed as a four‑in/four‑out arrangement, or entirely the other way around.

The TP3F is described as a “patchbay slice” and has numerous possible applications.

The TP3F is even more versatile. Because its rear panel provides two RJ45 connectors as well as a set of four jacks, you can either use it to provide a set of patch points within a cascaded Cat cable run, as a four‑channel converter between the two formats with patching built in, or even as a basic passive splitter. This opens up some interesting possibilities. For example, you could station a number of TP3Fs around the walls of a live room, connect them all together with Ethernet cable, and feed the entire system from a four‑channel headphone amp. Each musician could then take their headphone feed from whichever TP3F happens to be the most convenient. Alternatively, of course, you can mount multiple TP3Fs on a H100 to create a 1U patchbay with up to 24 inputs and outputs.

Ashton Research’s HF100 rack tray can hold multiple Tetrapatch units in various different configurations.

Patching Up

The entire system worked flawlessly for me, and although the cost of each Tetrapatch unit is not insignificant, it should be weighed against the cost, weight and inconvenience of the multicore cable that it eliminates. Every reorganisation of my own studio has meant frustrating hours trying to persuade heavy and uncooperative audio snakes to fit through holes or round corners, and a single high‑quality multicore can easily cost as much as several Tetrapatches once you get into long cable runs. Tetrapatch has made me a convert to the joys of AES72, and I eagerly await the day the system is expanded to encompass other connector types such as XLR and DB25.