Add 12V trigger to ZP90

  • 29 April 2010
  • 15 replies

Add a 15 volt switched plug (Sonos on power to the plug, Sonos off, power off to the plug) to the 90 so that it can power-on an amplifier by 'auto on'. Would make an awesome capability. Better than sound sensing. You could use your own amp as well as other electronics. Much Needed! Will increase 90's capability and sales!

15 replies


First post! Welcome to the forums.

I edited the thread title a little in an effort to aid other users when they search. "12V trigger" is the generic industry term for this feature.

This is a popular request, but it is tucked inside many threads. Let's use this thread to collect 12V trigger requests.

Here are some related threads:

"audiosense" > 12V trigger black box
ZP80 - Auto Power on for External Amp?
Low Power (Green) Mode

and a large thread discussing this and some general control topics:

External Source Control AKA The IR Thread
Userlevel 2
Hello all,

Wouldn't it be great if there could be a 12 volt trigger our on the 90? My outdoor speakers have very long runs and are power hogs(rockustics) but sound great when driven by a massive amp. Sorry, but the 120 doesn't them justice(it may have to do with the long cable runs as well)

But a 12 volt trigger would solve having to use 2 different remotes, the Sonos controller and the remote for the rest of the system. I can't possibly be the only one that could use this feature...


I'd take a voltage free trigger if we can't get 12v. Either works for me.
Dear trigger-fans,

here is a picture of my 12V-trigger-modded ZP80:

The 12V trigger is connected to the mute-button and of course also works with the remote. The trigger controls a 230V power strip (in the shown case the power strip contains another 12V wall plug because the trigger for my active speakers draws more power than the Sonos trigger can supply directly).

Unfortunately I can't answer any question about this MOD as it was done by a dear friend who doesn't have the time to publish details or answer questions. But maybe my picture will encourage other modders. (Please be sure what you are doing as faulty MODs may cause electrical hazards.)

Userlevel 2
Here's something else you could try. I haven't taken the plunge yet:

The three components (sensor, controller and power supply) should work together to (1) monitor an RCA signal for audio content; (2) send an "On-Off" signal to the controller; and (3) use the controller to send a 12V trigger signal to another component.

With a delay adjustable from 0 - 15 seconds (I'd MUCH rather that be 0 - 5 minutes or even more), this assemblage MIGHT allow you to run the Sonos analog audio outputs through the monitor (maybe even if you're using the digital outputs) to turn on and off your amplifier, etc., whenever you play music with the Zoneplayer. Using the mute or pause control should, in theory, cause the trigger to shut off the amp after 0 - 15 seconds.

Total cost less shipping looks to be about $82, which is cheaper than the alternatives I've seen around here, and the installation should be much easier than the relay mentioned in one thread. In fact, it should be plug and play, except you'll need to splice two wires of a mono miniplug cable into the 12VDC / GND sockets. For the "activating RCA connection" I would connect the sensor to one of my subwoofer input cables, since distortion or signal loss shouldn't affect the sub's performance.

My NAD C272 power amp has this feature built in, but its threshold is way too high. I need to crank the volume up to turn it on, and it turns off if the music is quiet. For that reason, I am a bit skeptical that this group of devices will be any better, but it really depends upon the threshold voltage and delay times. However, the device here does have adjustable sensitivity, too. Still, I might try it sometime and use the 30-day return policy if it doesn't work.

(Of course, if Sonos would only add a 12V trigger to the next Zoneplayer, none of this would be needed. :))
Userlevel 2
Also, if your amp or other component lacks a 12-volt trigger function, it looks like this $76 gizmo would basically add that function to your system, enabling the controller in my post above to turn the AC power on and off:

I realize that Niles Audio makes a lot of gizmos along these lines, but they're significantly more expensive and I'm not sure they even have an RCA power sensor like the one above.
Power sensing of SONOS ZonePlayers is not practical because the difference in power draw from standby and playing quietly is very small. (the ZonePlayers are very efficient)
Userlevel 2
Yes, I learned that one the hard way, Buzz; the smart power strip I tried wasn't smart enough to distinguish whether I was using my ZP90 or had it on stand-by.

But that is (perhaps) the beauty of the RCA sensor I posted just above. It looks at the output voltage of the Zoneplayer, instead of its current draw.

"(perhaps)" is the best way to approach those audio sensing schemes. They generally work for pop music and less well for classical that has long quiet passages. If you work at low output levels from the ZonePlayer, the sensors may be totally unsatisfactory.

Video sensing is much more reliable -- if an appropriate video signal is available from your equipment.

Sensing the power of the the A/V receiver or a receiver's 12V trigger is the most reliable scheme.
Userlevel 2
Unfortunately, my system is audio only, and I want to use my Sonos ZP90 to trigger / toggle the amp's power, so I can use my Sonos app to turn on everything just by hitting "play," and have it all turn off after a decent period of non-use.

I wish to heck the sensor I posted above had a longer delay option than 15 seconds. Ten minutes at high sensitivity should be enough to work with almost any recording, even at pretty low levels.

Oh well. When the next generation Zoneplayer is coming out and whether it will include a 12-volt output socket keyed to play/pause condition, are the big questions for me; but I get the impression that that information is not something you're at liberty to divulge. 😞

Stupidly, this 12V trigger issue has been bugging me for about two years now. I would love a simple solution!

Moderators are not SONOS employees. We have volunteered to help keep the forums neat and tidy. Sometimes we will be on a beta team, but we respect the non disclosure agreement.

Originally, SONOS was very, very closed about developments and members were not allowed to disclose that they were on a beta team. Currently, things are a little more relaxed and SONOS offered pre-release disclosure of its iPad project and recently has disclosed the Android project.

As each new feature arrives there are elated responses when "my" feature is added and rage because "my" (MOST IMPORTANT!) feature is still missing.
Userlevel 2
I hear you. I'm a volunteer moderator on a large car-based forum. I'm subject to different limitations, but I get the gist!
Userlevel 2
Recently, I posted a related note about the Radio Design Labs ST-ACR2 Audio Controlled Relay

I am using two ST-ACR2s and a smart power strip to control power to a surround sound processor and a power amp. In this way, I don't use 12v triggering and avoid keeping the amplifier in standby mode.

In my case, I want the power-on sequence to be surround sound processor first then amp; and the power-off sequence reversed. This will avoid the 'pop' that happens when the surround sound processor is powered on or off whenever the amp is 'on'. Here's a link to a diagram.


** EDIT: apologies, but the 'master outlet' and 'slave outlet' labels in the diagram are incorrect. Please swap them.

. 'ST-ACR2(60)' is a Radio Design Labs model ST-ACR2 set to a relay-release delay of 60 seconds.

. 'ST-ACR2(45)' is a Radio Design Labs model ST-ACR2 set to a relay-release delay of 45 seconds.

. Smart power strips are manufactured by many outfits, e.g., Bits Limited, Belkin. I used a Belkin, which has a useful relay delay (see below)

. ST-ACR2 requires constant 24v – 33v DC power

. Line level audio from ZP90 to surround sound processor not shown; interconnects between surround sound processor and power amp not shown, detailed connections on ST-ACR2 units not shown

. Audio input sensitivity of the ST-ACR2 is adjustable.

Line-level audio from the ZP90 that is above the sensitivity threshold set on the ST-ACR2s will close both ST-ACR2 relays. The power cord controlled by the ST-ACR2(60) is plugged into the Master outlet of the smart power strip so the surround sound processor obtains electrical power before the amp; power to the Slave outlet of the smart power strip is delayed a few seconds after the Master circuit is closed (a feature of the Belkin smart power strip). So, the power-up sequence is surround sound processor first, then power amp.

When line level audio from ZP90 goes below threshold, the relay on the ST-ACR2(45) releases after 45 seconds, resulting in the power amp powering down first. The surround sound processor is powered-down 15 seconds later because the ST-ACR2(60) has a 60 second relay-release delay.

The ST-ACR2 has a max switching (inrush) power of 60W, 2 Amps. [begin EDIT #1*] In the described set-up, the amp is powered-on after the surround sound processor. And, because we are talking about audio-controlled relay switching, the volume from the ZP90 must be above-threshold for the power-up sequence to initiate. Because the pre-amp will turn 'on' before the power amp, inrush current to the power-amp is an issue. Be careful to use moderate volume levels for power-up, or the relay on the ST-ACR2(45) may eventually burn out [end edit #1]. The ST-ACR2 has a max carrying current of 3 Amps, which should be more than adequate for any surround sound processor/pre-amp, but some amplifiers can draw more than 3 Amps at high volume levels. If your amplifier requires a higher carrying current [begin EDIT #2*] or you are concerned about inrush current to the power-amp [end EDIT #2], then an option would be to control the electrical power to the surround sound processor with the ST-ACR2(60) and let the smart power strip control power to the amp [i.e., no ST-ACR2(45) used]. Alternatively, if your amplifier has triggering, then its switching can be controlled with a 12v trigger from the pre-amp or 12v wall wart connected to the smart power strip, but this requires the amplifier to be in 'standby' mode sucking electricity when not in use. In my case, any solution employing only one ST-ACR2(60) and no ST-ACR2(45) unfortunately would result in a 'pop' whenever the ST-ACR2 relay was released (i.e., at system power-down because power to the preamp would be cut while the amp was still 'on').

Be careful! The AC 'hot' wire should be controlled by the ST-ACR2 units and the ST-ACR2s should be suitably enclosed. Do not attempt if you are not confident/competent with AC wiring.

Other thoughts:
(1) I wish the ST-ACR2 settings would allow it to be more sensitive to the level of the line-in audio signal. As it stands, the volume on the PC Sonos controller software (ver 3.3) needs to be set at least half way for the ST-ACR2 relay to close.

(2) Of course, the ST-ACR2 can be used to control power to a 12v wall wart, which could be used to control amplifiers with 12v triggered power switching.

(3) Although the ST-ACR2 documentation indicates that the maximum delay for releasing the relay is 50 sec (i.e., after line-in audio goes below threshold), I have found the max to be closer to 60 sec.

* edited on 28MAR2011
** edited on 02APR2011
*** edited on 24DEC2013 to fix link to the diagram
Anyone tried the triggers from Xantech that Zonker92 mentioned?