Input Connections

In the center are three 25 pin D-Subs. These are labeled Input A, Input B and Output. These are wired to match the popular Tascam pin-out configuration that was established when they launched the DA-88 recorder. Typically, the breakout cable would be a balanced D-sub to eight XLR or ¼” TRS connectors. In the most basic sense, depressing the front panel A-B input select switch toggles all 8 channels simultaneously. (Inside the SW8 are a series of relays that do the actual signal switching.)

As many of today’s multi-track recorders employ D-sub connectors for their audio i/o, D-sub to D-sub cables will often suffice. In effort to accommodate the various computer-based multi-track setups, two sets of ¼” TRS connectors have also been provided. Note that these are labeled A and B and are essentially wired in parallel with the two D-Sub inputs. The ¼” jacks will accept either TRS or regular mono ¼” instrument signals. A global -20dB pad accommodates both +4dB and -10dB levels.

Output connections

Just like the inputs, the outputs have also been doubled up, but this time, in a different manner. The D-sub output on the rear panel acts more like a ‘direct thru’ connection for the balanced signals while the front panel XLR outputs are transformer isolated mic level outputs. (There is method to this madness!)

Often, it is the ‘tech-head’ in the band (or the tech-head’s tech) that controls machines like computers, recorders, click tracks and playback machines. This invariably puts the machine and the SW8 on stage. This also means that the output of the playback system has to feed the snake, mic splitter, monitor console and front-of-house console at the same level as a microphone or direct box. Sending a +4dB or -10dB signal into a -60dB mic splitter would overload the input and cause serious distortion. The SW8 reduces the output to a mic-level to make this work.

The XLR outputs are transformer isolated as a means to reduce system noise, such as hum & buzz caused by ground loops. Invariably, the stage equipment will receive it’s AC power from a different leg than that of the front of house which will be connected and positioned some 300 feet (100 meters) away. This augments the chance for noise to enter the system. Transformers offer the best and most dependable protection against noise.

As a special extra feature, should you wish to keep the front panel clear of all cables and route the mic-level isolated outputs to the D-sub, this can be done by opening up the SW8 and simply relocating a locking multi-pin cable. (How do those guys at Radial think of all these things?)

Monitoring & Switching
Whether you intend to have the SW8 automatically switch or not, striping a test tone onto a track and having the SW8 monitor it for you automatically can save your behind!

It’s easy! Record any steady tone you like onto one of the tracks, a standard 1kHz test tone will work fine. The rear panel has a recessed knob marked ‘threshold’ that lets you set the switching point level. It works just like a signal gate only that when the signal falls below the threshold level, the SW8 will switch from input set-A to input set-B.

Unless of course you do not want it to… You may, only want the SW8 to tell you that there is a problem and that you would prefer to manually switch the system so that you are not being controlled by the evil robot inside the machine. This is fine. These options are built in because each system tech will have his set of priorities. So instead of automatically switching, the SW8 can be set so that the front panel alarm LED will illuminate to tell you a problem is at hand! You could use the contact closure to turn on a remote siren, strobe light or even have it connect to an intercom.

Toggling the Radial SW8’s A or B inputs can be done in a variety of ways:
1. Manual switch using front panel AB select
2. Footswitch connected to rear panel
3. Contact closure from an external device (ex: MIDI Controller)
4. Automatically switch by sensing a loss of signal
5. Be linked as a slave with another SW8 that is master

Most of these are self-explanatory. However, the intent may not be totally clear. For instance, you will note that the AB switch on the front panel is clearly demarcated as a focal point inside the control monitor section. Should a problem occur, this is where you eyes & focus will go to fix it. This would likely be how a stage technician would perform the task.

The footswitch option seemed like a logical option given the fact that often times, the keyboard tech-head is usually the one given the task of dealing with computers. Having a footswitch means the hands can be busily playing a fugue while the left foot can switch bands!

Using the footswitch input as a contact closure input opens the door to using the SW8 as part of an automated system that could literally reroute signals from one PA system to another to create effects. You could also use the SW8 to select a mix from two different stages without rewiring! Who knows… innovative engineers will likely find all kinds of weird and wonderful applications for the SW8 once they get thinking…

In auto-mode, the SW8 does the work. Link as many as you need with a cable and relax!

SW8 Specifications