DIY Twin 12v trigger switch for Mono block power amps

[Barwell1992]

Hi everyone.

First proper post on this forum!

So I've got a bit of an odd AV/Hifi setup with multiple pre amps running into a single power amp and speakers my issue is the amp has not trigger so i've decided to make a 12v trigger switch.

My current Sony TA-n55es power amp is quite old so has not trigger in and my wife finds this slightly annoying... Due to my mild impulsive nature i've decided to not only allow both of my pre amps to be able to power on the power amp but also have twin outputs so i can run two older amps with no triggers or two mono blocks etc.

Because i wanted to run more than one item from the switch i've chosen to use a Omron 20A solid state relay, this does have its downsides and will need additional passive cooling to run over 5A, the relay was chosen as my AV amp can only output 150mA over the trigger, this relay is ideal as it only requires 10mA to activate.

I've decided to use a IEC socket for the power into the unit and twin IEC sockets for the outputs to the amplifiers, the two 3.5mm 12v trigger jacks are Mono jacks and as I've got two pre-amps that i wan't to be able to power on the power amp(s) i've fitted diodes on the 12v+ trigger lines to stop feeding 12v from one pre-amp to the other.

Very basic schematic below.
12v Trigger wiring.2.jpg

Parts List:
1x Omron 20A G3NE-220T-US DC12, Relay £27.98
2x Nexperia 30V 200mA, Diode £0.48ea
2x Lumberg 3.5 mm Chassis Mount Mono Jack Socket 2-Pole £2.48ea
1x IEC inlet 4.8mm faston £1.23
2x IEC Outlet 4.8mm faston £2ea
1x Pentium CPU passive 50 x 50 x 25mm cooler £3.49
1x Thermal grease £1.45
1x Alu enclosure (150x105x55mm) £13.99

Total cost £58.93

so not exactly cheap but I've got a little over the top..

few photos below
case
Alu Case.jpg
Relay and heat sink
omron.jpg
most of the parts
Trigger parts.jpg

Just waiting on the Alu enclosure then i'll get to work and let you all know how i get on with loads of photos, the enclosure will have quite a bit cut out of it so might take me some time.

Cheers,
Dan