A staple for turntablists for years was the switch on the mixer that toggled between the phono input and the line input. Originally designed to allow a DJ to easily switch between two devices plugged into the same channel, and get double-duty from one channel on a mixer, the switch was quickly repurposed by scratch DJs. As with most functions on a turntable or mixer, DJs found a use for the switch other than that which the manufacturer intended. This is the norm. Pitch control was made to adjust the pitch on a record that was cut at a speed other than 33 1/3 or 78, but DJs discovered they could use it to beatmatch. The crossfader was made to smoothly transition between two songs, but DJs discovered the could use it to scratch. The list goes on, and near the top of that list of repurposed features, one finds the line/phono switch.
When switched up, or on, into phono mode, the audience hears the record, much the same as when the crossfader is opened. When switched down, or off, into line mode, the audience hears silence, unless a device is plugged into the line input on that channel, and playing, in which case they’ll hear that.
How is this useful? It’s incredibly useful for making fast cuts. Faders at the time did not yet have adjustable curves, so a scratch like the transformer, which requires quick on/off clicks, sounded better, or at the very least different, when done with the line switch. In fact, the adjustable curve was invented to allow crossfader scratchers to have the same precision as those who used the switch. This became a necessity in the early ’90s after the invention of the now-ubiquitous Flare scratch. That scratch can only be performed using a line switch, or with a crossfader with an adjustable curve.
Why am I bringing this up today? Because the line swtich is inexplicably absent from modern mixers. For scratch DJs who started in the ’80s, that switch was a necessity, and for any DJs who scratch in an up and down motion, i.e. on the volume fader rather than the crossfader, the lack of a line switch can be a deal-breaker. Yet, as none of the current high-end mixers have such a switch, said DJs are forced to make a deal regardless. I’m one such DJ, and a few years back I bought the last new Vestax PMC-05ProIV mixer in my local shop, despite it being a dated mixer at the time, simply to have access to a line switch.
One workaround is to cut a thick piece of cardboard to fit the upfader slot, and effectively shorten the throw of that fader to the point where using it is similar to a click, then setting the curve on the fader to fast. It isn’t the same, but it’s close. I’ve seen DJs use tap to shorten the throw on a volume fader, which also works. The problem there is you lose the ability to use the fader to fade the volume in and out. I’ve dreamed up all sorts of modifications to mixers to fix this problem, but have yet to put any to the test; further details as events warrant.