Automatically switching on a power amp that doesn't have a 12v trigger - solution

Rwatkins

Novice Member
I've been trying to figure out a solution for automatically switching on my power amp on when my AVR is on.
My AVR as a 12v trigger but the power amp doesn't.

This looked like a suitable product
AUDIOPHONICS Trigger 12V 230V Slave Power Supply Device - Audiophonics
but my PA has a captive power lead.

I also considered a DIY solution but then remembered I had one of these that has done the job

The AVR current draw in standby is sufficiently low to switch off the PA and high enough when on to switch them on.

Lots on eBay inexpensively, thought it might help someone with the same problem.
 

Zarf2007

Active Member
see also my post here:

 

simon194

Well-known Member
I had seen that but my power amp has a captive mains lead so it was going to need some adaptations to work.
One of these will do the trick. Link
 

Dobbyisfree

Well-known Member
I'd like to bring this thread back to life please. Two questions:

(1) Is the Audiophonics product the only one that does this, or are there different shaped alternatives? Or one that is "in line" so that it is part of the power lead and can be hidden?

(2) On the basis that the power amp needs its power switch left on, is there any damage that can be done by it being powered on and off by the power being cut?

(3) I'm not incredibly lazy (honest) would it just be better to power up the amp when the TV goes on and then power down before bed? I.e. most days it may be on all day? I don't care about the power consumption, more concerned about the unit's health.

Thanks.
 

Dobbyisfree

Well-known Member
@AndreNewman if you have the time please can you help with questions 2 and 3?
 

AndreNewman

Active Member
I'd like to bring this thread back to life please. Two questions:

(1) Is the Audiophonics product the only one that does this, or are there different shaped alternatives? Or one that is "in line" so that it is part of the power lead and can be hidden?
There's loads of solutions, most are DIY though, don't know why there aren't many ready made solutions.

I built a couple of trigger boxes around these:


The board is low power enough (I measured 30mA) to be powered and triggered by the 12v from the AVR or processor.
But the relays are not up to much, the one running my subs welded it's contacts closed after a movie with some serious sub bass, no not Edge of Tomorrow. So I replaced the board with a spare and put a 40A mains relay on the output.

The one running my 30 year old amps with no inrush protection is going the same way so I bought one of these instead:


Like this in the back of the rack, four IEC leads coming out to four amps, 30A relays so should be good:

21-06-10 10-22-55 4798.jpg



Be wary, Audiophonics now has a €160 (ex tax) minimum order limit due to Brexit customs paperwork. Took me two weeks to get my last order!

(2) On the basis that the power amp needs its power switch left on, is there any damage that can be done by it being powered on and off by the power being cut?
If it's just an amp, no DSP, no web interfaces, apps, then no problem to just cut the power.

Most electrics/electronics fail on power up (think about when a light bulb fails most often) so leaving stuff on all the time is usually best for long life. Not best for power use or heat generation though!

(3) I'm not incredibly lazy (honest) would it just be better to power up the amp when the TV goes on and then power down before bed? I.e. most days it may be on all day? I don't care about the power consumption, more concerned about the unit's health.
What kills electronics is extreme heat or power cycles.

The softstart box will probably significantly extend the life of my amplifiers. I have softstart dimmers on all the bulbs in my house too, Halogens last for, don't know how long, they haven't failed yet...

I wouldn't put a softstart unit on stuff with DSP and modern electronics, it will have one already and it may not play well with an external unit!
 

The latest video from AVForums

Podcast: The Best TVs of 2021, plus our favourite & memorable reviews of the year
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom