Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems 861 Trigger, is it a constant 12V?

Hi.

I know the 861 trigger is a 12v trigger. However, is it just a pulse or a constant voltage?

Thanks

The trigger is a constant 12v output.

Regards Ronald

Do you think it is possible to reverse? I know it's programmable to a point (on or off). I only ask as I have built a custom Hypex Ncore three channel amp. The power supplies have have a standby trigger that requires a constant 12V signal to stay in standby. So the 861 would need to output the 12v signal, when in standby.

Typing this, I doubt it, so I do have an alternative. However, if possible, it would have been a very elegant solution.

Thank you.

Hi,

I'd just try it. configure up the 861 trigger as required and the put a voltmeter on it to see what happens when it's put in to standby.

Regards,
Carl

The trigger does not deliver any voltage on standby.

Assuming the devices you are controlling require minimal current to drive them (likely), a simple 3 component circuit can invert the control signal - this will give close to 12v output when the input is low, close to 0v when it is high. The transistor BC337 is a widely available European transistor, it should be easy to find a US equivalent.

It requires a 12v power supply which you can probably pick up from one of the Meridian comms sockets, otherwise from a simple wall-wart.

Alternatively, if want to achieve ground isolation between the power supplies and the Meridian box, you could use an optical isolator. In this case, the 12v power supply for the right hand side would need to come from other than the Meridian.

Or a 12v relay...

You could certainly use a relay in theory though the 12v trigger output is only rated to supply 100 mA - at least on my G91. Assuming this is the same with the 818, this would not be enough to run most relays and you would in any case still require the 12v external supply.

If you're able to source a 12v relay with a coil resistance of 120 ohms or more, this is what you'd use...



The diode across the relay coil is important to suppress the voltage spike generated when the relay is turned off and so prevent cooking the 818.

Does anyone knows how I can change it to 10v? I bought a new amp and it has a 10v trigger. I have to lose 2v.

Ronald

Use two resistors:-

Potential Divider

Thank you for your post, i do not have alot of knowledge of electronics. I see what is possible but don't know how to make it.

I will take your input to my dealer and hope he can make it for me.