Warning

IN THIS Article I Volition BE DISCUSSING TAKING THE Encompass OFF AND ALTERING THE WIRING OF EQUIPMENT THAT OPERATES AT 240 VOLTS. THIS IS NOT AN INSTRUCTIONAL Commodity, IT IS JUST A SUMMARY OF WHAT I DID. IF YOU CHOOSE TO DO THIS YOURSELF, Y'all Do And so AT YOUR OWN Risk AND SHOULD BE CONFIDENT THAT YOU KNOW WHAT Y'all ARE DOING. YOU Will ASLO LIKELY VOID Whatever WARRANTY!!

New Amp!

I recently purchased a new amplifier to replace my venerable merely ageing Pioneer A400. It served me well but despite the rave reviews dorsum in 1990 I have to accept that was was great back then is probably a bit mediocre past todays standards. I already had a Cambridge Sound CXN media streamer which has a perfectly good digital pre-amp, and then I went for a Nord One MP NC252 250W NCore based amplifier. No need to spend money on a bunch of stuff I didn't need! Colin Northward at Nord Acoustics hand builds all the Nord gear, great service and e'er at the end of the phone, I can highly recommend.

Y'all can come across here where the trigger switch input would take been had I taken the option.

Trigger Switch Option

At the time of buy there was the selection to add a 12 volt trigger switch. A trigger switch is basically a powered switch which operates on a bespeak from somewhere else. In this case, I would desire the power amplifier to switch on when the pre-amplifier, that is my Cambridge Audio CXN, is switched on. The problem here is that the CXN does not have a 12 volt trigger switch output. Also equally this small issue it was a £50 choice from Nord, so I didn't cull it when I bought the amp.

Some other Solution!

Sometime afterwards purchasing the amplifier, I was randomly reading some stuff on a how-do-you-do-fi forum where someone was discussing the possibility of running a trigger switch using the power from a USB port. USB operates at v volts, then if you had a 5 volt switch, in that location is no reason why this wouldn't work. Now, the Cambridge Audio CXN has a USB socket in the back for connecting media drives etc. First affair to check was that the CXN USB port powered on and off when the unit is switched in and out of standbay, which thankfully it does. If the USB port remained powered in standby obviously switching wouldn't piece of work.

And so then, all I needed was a unmarried channel 5V Relay Module that could activate 240V. This sort of thing is readily bachelor on eBay or Amazon. I would recommend making sure yous buy a decent brand like Songle, these are inexpensive enough then no reason to buy cheaper copies. For anyone not familiar, a relay is a means to use a low voltage to switch a higher powered current/voltage, usually via a solenoid. They are used a lot in cars, for case, to keep all the high amp stuff well away from behind the nuance, reducing both the size of wiring and the risk! If you want a good caption of how a relay works in detail accept a look here.

A Few Inexpensive Parts Later

So, a relay module for less than a fiver, a couple of quid on a 3.5mm mono jack socket and plug plus an former USB cable and I'm all set up. At lot less than £50! You lot tin can get away with just the bare relay, a module just makes the wiring easier plus you get a light when the switch is agile!

Stripping the terminate of the USB cablevision you need to detect the blood-red +ve and black -ve wires. Any other wires you demand to tape dorsum out of the waya nd make sure they don't touch anything, including each other.

You also need to decide how you are going to run your cablevision into the amp. The Nord amp is pretty uncomplicated and already has a spot where the optional trigger would be. Simply a matter of carefully drilling through the back panel, wiring upward a piece of the cut USB cable inside the amp to the 3.5mm mono jack socket and relay.

I drilled a hole through the back panel. Adequately easy through aluminium. I could have as well just fed the wire through one of the vents in the summit panel.

With the pigsty drilled, I fitted the mono jack socket. It is easier if the socket & Jack are mono equally there are simply two wires, +ve and -ve/ground. Most you will see for sale are 'stereo' with three conductors. Y'all can utilize stereo socket and jack, but make certain you lot brand the right cnnections to consummate the circuit.

So plumbing equipment a mono iii.5mm jack to the end of USB cablevision that still has the large USB plug that will fit in the back of the CXN'south USB media connectedness. Another pick would accept been to run the wire through 1 of the vents.

This relay is fitted to a PCB and has a -ve, a +ve and a indicate (due south) terminal on the v volt side. I connected the positive wire to +ve and South terminal together as I won't have a split signal.

The 240v side has a center common terminal and then an NO (usually open) and NC (normally airtight). The positive power wire in the amp needs splitting and connecting to the NO and mutual terminals.

Inside the Nord amp it'south pretty like shooting fish in a barrel to encounter the power cablevision that I need to add the switch to.

Putting it All Together.

After disconnecting the power plug from the amplifier main board it was simply a matter of untwisting it and cutting the +ve (brown) wire. Stripped the ends and connected up to the Commonly Open up and Mutual terminals on the relay board. The switch is now ordinarily open but when a 5 volt supply is applied to the other side via the CXN USB outlet, the switch closes completing the circuit and the amp switches on! Of grade, I accept to leave the amp rear and front power switches in the on position. Then it's merely a matter of sticking the relay somewhere where it isn't going to interfere with anything else. I used a bit of Velcro record to stick it downwards as seen below. This detail module has a carmine LED that lghts upwards when the switch is active which gives a reassuring glow through the acme amp vents.

Hither you can come across the +ve power wire split and connected to the Mutual and Normally Open (NO) connections

Conclusion

And then there you have it, a trigger switch set up for less than a tenner. All you need is an output voltage off some sort from your principal unit, in this example the Cambridge Audio CXN USB connection. It doesn't necessarily have to be called a trigger switch output and it doesn't accept to be 12 volts!

Happy to reply any questions beneath if I tin.