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.
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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
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Relay and heat sink
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most of the parts
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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

[Firebottle]

Good project Dan.
I put a solid state relay into an Aiwa tuner so that the power amp could be controlled.
Due to the (very) small leakage of said relay and the amazing sensitivity of modern LED's I have a tiny illumination of the power amp LED when 'off'.

Never been bothered about it though as the system is in the workshop.
:)

[Barwell1992]

Decided to add a on/off toggle switch to the main feed so i can kill the whole thing, also chosen the 240v cable and terminal blocks.

Switch is: Arcolectric DPST Toggle Switch C1750HOAAI (20A 250V ac)
Terminal blocks are: Wago 221 Terminal Block Connector, 3 Way (32A 450v/ 20A 600v)
Cable: 240v 2.5mm2 high temp flex

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[Barwell1992]

Currently trying to fit a Filter into the box as well, looks like it’s going to be too small. I might remove the duel output and move the filter to a new box that run inline after the switch, from that point it will then spur back to two outputs, bit messy though.

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[Barwell1992]

So in the end i've decided to add two 250v 10A RFI filters onto the output of the power unit/switch with twisted L/N running from the units to the outputs.

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I've also purchased a larger enclosure, this allows me plenty of space and will provide the option to add other items if i wan't at a later date, including the option to supply the unit with a true 20A rather than the 13A max the plug can supply.

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[Barwell1992]

So the unit is finally built and works really well.

https://youtu.be/e83qWAspNH8