Do you have a complex audio or home theater system and have trouble getting everything to turn on at once? I do. While everything downstream of my Pre-Pro has 12V trigger control, my processor has but one 12V trigger.
Emotiva makes an inexpensive 12V trigger hub/expander to solve that problem, the ET-3. The ET-3 takes in a single 12V trigger input and provides three high-current 12V trigger outputs. That “high current” part is important: if you have more than three triggerable components, you can use headphone splitters or the components’ trigger pass-throughs and trigger more than three downstream processors or amplifiers.
The ET-3 could not be easier to use: plug in the 12V trigger from your AVR or Pre-Pro into the ET-3’s input, and connect its outputs to your downstream components’ trigger inputs. The ET-3 even comes with four stereo minijack trigger cables!
Just be aware of different 12V trigger standards. The vast majority of home audio 12V triggers use standard stereo 3.5mm (mini-jack) headphone cables. However, mini-components (such as the Parasound Zamp above or and the Pro-Ject Amp Box below often use 2.5mm trigger jacks, like the headphone jack on the original iPhone. Monoprice carries 3.5mm -> 2.5mm headphone cable adapters for about fifty cents each.
Also, some components require mono triggers. For example, my mighty ATI AT2007 amplifier simply ignores trigger commands delivered over a stereo (TRS) plug. The AT2007 requires a mono (TS) trigger cable, which ATI supplies in the box. The ET-3 doesn’t care. It will drive stereo or mono cables.
If your AVR or preamp lacks a 12V trigger but has a switched outlet, as many older components do, you can still use the ET-3 to trigger downstream amps. It has a mode where it will fire triggers as soon as it has power. So just plug the ET-3’s power supply into a switched convenience outlet, and you have three triggers that turn on when you turn on the AVR or preamp.
If your AVR or preamp has neither a trigger output nor a switched convenience outlet, you can turn the ET-3 on via a “smart” power strip with your preamp or AVR plugged into the “master” outlet. That is a better solution than plugging your amp itself into the smart strip, because such strips may limit current.