Auto power on amp

  • 5 February 2015
  • 13 replies
  • 12843 views

I have a Sonos Connect connected to an amp (more accurately a pair of active studio monitors, but effectively the same). Every time I start playing music for that room I need switch the power socket on for the multiplug that they're powered from. Other people may have amps that auto switch on when they detect an input signal but that's not an option for me.

I would have thought its fairly common issue but I'm really struggling to find a solution.

There's this discontinued product, the Parasound SCAMP:
parasound.com/pdfs/vintage/scampom.pdf
(Sorry, this forum won't let me post clickable links until I've posted 3 times!)
Which while being on ebay is expensive, but more importantly the wrong voltage (and ideally would be better with kettle style power outputs, or at least UK sockets).

I also found this, the ST-ACR2:
rdlnet.com/product.php?page=278

But I have no idea how to hook this up, and even if I could I'd up up which a bunch of exposed wires on the shelf.

Can anyone guide me to an elegant solution? I know flipping a switch on (and remembering to turn it off again) isn't the biggest hardship in the world but I'm trying to get a simple and seamless system as possible running, especially for other people to use when I'm not there.

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13 replies

Userlevel 3
Badge +1
Well, the most "elegant" solution is certainly a Sonos AMP. :D

Why not switch out the Connect vs an AMP?
I have a Sonos Connect connected to an amp (more accurately a pair of active studio monitors, but effectively the same). Every time I start playing music for that room I need switch the power socket on for the multiplug that they're powered from. Other people may have amps that auto switch on when they detect an input signal but that's not an option for me.

Why do you need to turn off the power to the actives? Most modern ones go to low power consumption - 0.5w - standby mode after some time of no signal and sense incoming signal to turn themselves on again.
Seems to me that if your model doesn't do that, exchanging it out for a pair that does is the simplest solution. If leaving the ones you have always on isn't an option.
Userlevel 3
Badge +1
Oh, should have read the "active monitors". In that case the AMP does not make sense. 😮
Why do you need to turn off the power to the actives? Most modern ones go to low power consumption - 0.5w - standby mode after some time of no signal and sense incoming signal to turn themselves on again.
Seems to me that if your model doesn't do that, exchanging it out for a pair that does is the simplest solution. If leaving the ones you have always on isn't an option.


They are not low power consumption. They are worth a couple of grand so "exchanging it out" is not an option!
I have AVI actives plus subwoofer and there's a hefty switch-on current. I'd never use anything other than a fully rated mains switch to isolate them. That ST-ACR2 looks much too puny.

And no, they don't go into standby.
Userlevel 3
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They are worth a couple of grand so "exchanging it out" is not an option!

And paying the electricity is not in the budget then? :D

Back to topic: what about a simple power plug with timer? So you could power the speakers down at times they are not used. Another solution would be a RF controlled power switch, there are even "app controllable" power switches. There are even IR controllable power switches, which you could integrate in a Logitech Harmony startup sequence.
Userlevel 4
Badge +14
There are a few other threads in this topic:

http://forums.sonos.com/showthread.php?t=16545
http://forums.sonos.com/showthread.php?t=18630
http://forums.sonos.com/showthread.php?t=30273

There are current-sensing power strips as well, but they will probably not work because the difference on a CONNECT between playing music and not, is slim.

Depending on your DIY skills, another solution would be a power strip or relay driven outlet controlled by a networked device (a raspberry pi for instance), or an audio sensing device with adequate delay. However, it might be difficult to identify low-level signals (line-out) compared to speaker level output (which is more common, I think). Some basic ideas can be seen here:

http://geraldnaveen.blogspot.se/2013/04/diy-raspberry-pi-controlled-power-strip.html
http://tech.iprock.com/?p=10030

However, I do not recommend these solutions unless you are very experienced with electric circuits and know some basic programming. You should at least use some pre-made, isolated relay controller like this:

http://www.adafruit.com/products/268


Which in theory should be controllable directly from the GPIO pins from a raspberry pi. The pre-made one seems to be for 120V, for a 240V you need to build it yourself using their kit.

http://www.powerswitchtail.com/Pages/PowerSwitchTail240vackit.aspx
Frankly I'd prefer RF-controlled mains power switches, and forget all the auto-sensing hassle. It's not hard to press a button on a remote when you actually want to fire up the serious HiFi gear.

With two grand's worth of kit you don't want the power-amps flicking on and off when spurious audio signals are detected, perhaps by someone somewhere with a Sonos controller who accidentally taps Play in that room.
Userlevel 3
Badge +1
I have AVI actives plus subwoofer and there's a hefty switch-on current. I'd never use anything other than a fully rated mains switch to isolate them.

Same situation here. Exactly the same situation to be honest if you're talking about the ADM 9.1 plus sub :)
Or maybe even the new DM10?:rolleyes:

Anyway, I'm using one powerswitch to switch on/off the connected active monitors.
Userlevel 2
Hello Everyone
I was pondering on the same matter for months now.
My main criteria were:
1. to get a good power amp (100W-8 Ohm / 150W-4 Ohm) under 1000 Swiss francs to power my Q-Acoustic i2050
2. Auto standby less than 1 Hour when music stops
3. Auto power on when music starts playing from Sonos connect

The only amp I could found in the market was Cambridge Audio Azur 651W. It sense the source music from it's audio in and turn itself on. After inactivity of 30 min it goes to standby.

Works like a charm.
Badge
Thank you Jishi for all you have created for us! In hopes of publicizing my small new (open-source) offering widely without being too spammy:

"SonosAmpJuicePi"- solution for automatically powering on/off amps
https://en.community.sonos.com/advanced-setups-229000/sonosampjuicepi-solution-for-automatically-powering-onoff-amps-6756435
Userlevel 1
I used an RDL ST ACR2 Audio controlled relay. When my connect sends a signal to my amplifier, the RDL module senses it, and activates a relay to power on my amp. If I turn the zone off, the amp goes off after an adjustable delay.
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I used an RDL ST ACR2 Audio controlled relay. When my connect sends a signal to my amplifier, the RDL module senses it, and activates a relay to power on my amp. If I turn the zone off, the amp goes off after an adjustable delay.

That is a great solution, too. I went a different route because I was not confident I could satisfy my own priorities using audio input sensing. I’m not sure how many amps you have, but in my home I am independently turning off or on 4 of them (each associated with a different Sonos Connect). Two of my top priorities were to minimize 24 x 7 power consumption and to minimize cost. The RDL ST ACR2 costs $99 and appears to draw about 1.2 Watts if I interpreted the specs correctly. I would have needed four of them, so about $400 and a 24 x 7 power draw of perhaps 4.8 Watts. My memory is hazy, but my Raspberry Pi 2 cost perhaps $60 and draws around 1 Watt. Other advantages I like to think it has over the audio input sensing approach include not having to fine-tune input sensitivity; knowing that an amp will never unexpectedly turn off due to a quiet musical passage or someone wanting very low volume music; and having listening continuity occasionally improved by virtue of the way that SonosAmpJuicePi gives a generous reprieve to any amps that are about to be turned off, for as long people are still making adjustments of any kind (changing music, volume, groupings etc.).

Tangent: I am happy to report that SonosAmpJuicePi continues to work great for me with no modifications or maintenance, including after incorporating Alexa voice control into my setup.

Again, I’m very glad to hear about different solution that also works well. Enjoy the music! 🙂