SOLUTION: Missing 12-Volt Trigger for Stereo Amplifiers and TVs
12-Volt Trigger for Stereo Amplifiers and TVs
A 12-volt trigger is a simple control signal used to automatically power audio and video equipment on or off. It is not an audio signal and it does not supply operating power. It is a low-current DC voltage, typically 12 V, whose only function is to signal state: voltage present = on, voltage absent = off.
What a 12-Volt Trigger Does
Most modern amplifiers, preamps, AV receivers, power conditioners, subwoofers, and some TVs include a 12 V trigger input (and sometimes an output). When the device detects 12 V on this input, it switches from standby to active mode. When the voltage disappears, it returns to standby.
Key properties:
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Voltage: usually 12 V DC (some devices tolerate 5–15 V)
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Current: extremely low (typically <50 mA)
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Connector: 3.5 mm mono jack (tip = +12 V, sleeve = ground)
The trigger replaces manual power sequencing. Instead of turning on a TV, then a preamp, then an amplifier, a single trigger event powers everything in the correct order.
Why Triggers Exist in Stereo and Home Theater Systems
High-power amplifiers are designed to remain in standby until needed. This reduces:
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inrush current stress
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heat generation
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unnecessary wear
A trigger allows a control device (TV, preamp, streamer, processor) to command downstream equipment without IR remotes, HDMI-CEC behavior, or network logic. It is electrically deterministic and immune to software errors.
Using a Simple Wall-Wart Trigger
A common misconception is that a trigger must come from another audio component. It does not.
Even when your pre-amp has no trigger output, there is a solution.
A basic 12 V DC wall wart can function as a trigger source.
Required parts:
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12 V DC wall-wart power supply (regulated, center-positive preferred)
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3.5 mm mono trigger cable
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Amplifier (TV, pre-amp, etc.) or any other device with a 12 V trigger input
Connection:
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Wall wart DC output → trigger cable
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Trigger cable → amplifier trigger input
When the wall wart is powered, the amplifier turns on. When power is removed, it turns off.
This works because the amplifier only senses voltage presence. It does not care where the voltage originates.
Voice Control with Smart Assistants
By combining the wall wart with a smart plug, the trigger can be controlled by a voice assistant.
Examples:
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Smart plug connected to Google Home
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Smart plug connected to Alexa
System logic:
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Smart plug supplies AC power to the 12 V wall wart
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Wall wart outputs 12 V DC
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12 V appears at the amplifier trigger input
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Amplifier powers on
Voice command:
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“Turn on stereo”
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“Turn off amplifier”
The same action can be executed using:
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voice commands
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smartphone app
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remote controls compatible with Google Home or Alexa
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automation routines (time-based or activity-based)
No modification of the amplifier is required.
Practical Advantages
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No infrared line-of-sight issues
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No HDMI-CEC instability
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No network dependency at the amplifier
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Works with legacy and high-end equipment alike
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Predictable on/off behavior
This approach is especially effective for power amplifiers, which often lack network control but include trigger inputs.
Electrical Safety and Compatibility Notes
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Use a DC wall wart, not AC
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Confirm polarity (most triggers expect tip = +12 V)
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Do not exceed manufacturer voltage limits
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Use mono trigger cables, not stereo TRS cables
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Trigger inputs are signal-level only; never connect speaker outputs or high-current supplies
Most modern amplifiers tolerate a wide trigger voltage range and draw only milliamps.
Adding a remote control to a 12 Volt trigger
You can also control the same smart plug without voice commands by using a programmable universal remote such as the SofaBaton X1S Universal Remote with Hub and App.
The SofaBaton hub integrates with Wi-Fi–based smart plugs and allows you to create activities that switch the plug on or off as part of a single command.
Pressing one button on the remote can power the smart plug, which activates the 12-volt wall wart, which in turn triggers the amplifier or other connected device. This provides deterministic, tactile control that does not depend on voice recognition and works even in silent environments.
The device supports up to 60 IR, Bluetooth, and Wi-Fi components and is configured centrally via the companion app. Product listing: https://www.amazon.com/SofaBaton
Summary
A 12-volt trigger is a simple, robust control mechanism for stereo amplifiers and TVs. It converts a basic voltage signal into reliable power sequencing. By combining a 12 V wall wart, a trigger cable, and a smart plug integrated with Google Home or Alexa, any trigger-equipped amplifier can be controlled by voice commands or smart remotes. This solution is hardware-level, deterministic, and independent of software ecosystems inside the audio equipment itself.
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We can send you a tested smart plug, plus wall wart, plus trigger cable. Finished, tested and ready to use for your equipment. Overall it’s just $50 (shipping included). Just send an email to “mail @ vidfame.com” with subject “12 Volt voice controlled trigger” – or use the following form.
