My amplified IEM combo cable

Danny1969

So I've made a lot of IEM combo cables for people over the years. This is a cable I invented for myself that basically acts as a normal guitar cable but also carries a stereo IEM feed as well. Previous designs have used headphone amps in pedal or box format on the amp or pedal board and the combo cable carried the headphone amp signal. For this new prototype I built today I have built a headphone amp into the IEM breakout box so no separate headphone amp is needed. The amp delivers 150mW per channel and can run from 5.5V to 24V ... it's wired for standard pedal power neg centre and protected against reverse polarity. The input to the amp can be stereo unbalanced or mono . As the breakout box has a socket for the last portion of guitar lead any colour or kind of straight or right angled lead can be plugged in. I've used a yellow straight ended cable in the picture. 



Here's a gut shot of the breakout box, as this is for myself and a prototype it's not that neatly done as it takes a while to work out how best to route things 



And no gadget is complete without the obligatory on LED 



The actual cable is Vandamm Blue series 2 pair. One pair carries the ground, left and right signals to the headphone amp. The other cable carries the guitar ground, hot and +V for the amp. It's good cable, doesn't kink and is very robust. The breakout box is a standard potting type box and you can get these in various colours. The jack socket is the very low profile Neutrik type.

The parts cost for this run to about £25 but well worth it as there's no interference noise like you get with cheap wireless IEM systems and you don't need batteries for this .. it runs off 9V pedal power or any other 5.5 to 24 adapter. Why Shure use batteries in their wired IEM's is  beyond me. DC voltage adds no noise to the system. 

If anyone wants to build their own IEM cable and needs some pointers on how to do it just ask.