12v trigger on an HCPC


Active Member
I have a 5 channel power amp that has the facility to be put into standby via a 12v trigger, e.g. from a suitable pre-pro. Unfortunately I cannot afford the matching pre-pro (since it is £2.5K) and I am anyway aiming to use my HCPC to do everything that the pre-pro is supposed to do.

Is there any way of setting up an HCPC so that it can handle 12v triggers? I presume this would also be useful in the future for controlling projection screens etc. etc.



Standard Member
How about this? I think it's for mains switching rather than 12V, but it may do the job (and a lot more besides - control lights etc too?). They may have other kits of a similar nature.


Standard Member
Surely if you need to output a 12v on/off from a pc you can just run the +12 from the powersupply to trigger the switch.


Standard Member

Did you find a solution to the 12v trigger problem?

Which method did you use, relay or direct from the PC power supply.

Has anyone solved this problem? Would X10 work?


Active Member
No - I have sort of given up on this one, since I didn't find an easy solution where I would have had confidence in not blowing up my power amp! If there is a good solution for this out there - I'd still be very interested.



I've seen a multi-way power block with a 12v trigger input- when this is activated it switches on the plugs.

Not sure where this is available, but will something like that do?


Active Member
Originally posted by KarlRobinson
Surely if you need to output a 12v on/off from a pc you can just run the +12 from the powersupply to trigger the switch.

That would probably do the trick, but the problem is you really need a delay mechanism of some kind in order to prevent a collosal "thump" when your soundcard is initialised by the O/S. Again, when you turn the PC off you really want the amp to have been off for a while already in order to not rape your gear and bust your eardrums.



Standard Member
That's my prob at the moment. I built a 4 channel power amp for the surround channels, and added a relay to mute the outputs. This is triggered by the 5V rail from the PC. I've added a 555 delay circuit with the relay, so it isn't triggered until 10 seconds or so after the PC fires up. All well and good - but shut down is still an issue.

I'm still considering one of those PC controlled power relay boards, as I could then control lights etc too.


Standard Member
Looking at the Cyrus web site, they have a power amp which switches from standby to on when it senses a signal. Would this solve the problem when connecting directly to a HTPC sound card?

Would you still have a "thump" each time the amp powered up?


Standard Member
Resurrecting an old thread.

I presume that things have moved on in the past two years. Did anyone come up with a solution to the problem?



Standard Member
This might provide a suitable option:

Masterplug Master Series Intelligent Energy Saving Extension

  • 8 socket extension lead with surge protection.
  • 3m cable.
  • Automatically cuts power to 5 slave sockets when the master is turned off. ;)
  • 2 sockets remain live for connection of fax machines or video recorders.
  • Includes telecom/modem/ethernet and broadband surge protection.
  • Audible surge alarm with power on/slave on indicators.
  • Ideal for small office/home office or audio video equipment.
  • UK £5,000 connected equipment warranty.


Distinguished Member

My cheap solution

Keep the amp turned on
Mute the sound
No thumps and 5K will cover the increased electricity costs


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