[alwayshungry]

Hi everyone,
My beta 22 build is going pretty well and I'm looking to finalize the wiring for the power. I'm using dual sigma 22s but also need to wire up a 3rd toroid to power my attenuator (Joshua Tree).
I'm planning on using an unlit bulgin power switch. I assume I need to hook this up to a relay but how do I wire it to turn on 3 circuits (the 2 for the sigma22s and one for the other toroid)?

 

[digger945]

If your Bulgin switch is only rated at 50mA then you will need a relay powered by a latch that is powered all the time. One example of a latch would be the epsilon24 power switch driver from AMB. The relay is to switch the 120/240V mains power between the inlet and the torroids.

http://www.amb.org/audio/epsilon24/
http://www.amb.org/audio/sigma22/ <- where you see the "switch" is where you could put the relay.

 

[alwayshungry]

Yeah I was hoping to avoid adding another board to this project so that's why I went with an unlit button. This is the switch I'm planning on using
http://www.bulgin.co.uk/Products/Swi...050_Switch.htm
Correct me if I'm unclear but can't I have the relay powered by the power mains and just use this switch to toggle the power on and off to the toroids?

 

[digger945]

If your switch is the one in the link then it's momentary so if you want to use it then you'll need a relay to hold the power on.
Yes you can have a relay that is both powered by mains and switching mains and the Bulgin will turn it on but how will you turn it off?
I am unaware of a relay that senses a momentary switch to both turn on and off, and I have looked.
I am referring to a mechanical relay with a hold circuit, the hold circuit will need to be made "open" to release the relay to turn off.

 

[Gatsu]

This was something that I worked on for a while with mine. In the end I went with a picaxe08M controlling everything.
I also feed back the + and - power rails on the Sigmas through optocouplers to the picaxe. If any power rail drops out it will flash an error code on the LED in the Bulgin switch.

 

[TimmyMac]

Quote:

Originally Posted by digger945 /img/forum/go_quote.gif If your switch is the one in the link then it's momentary so if you want to use it then you'll need a relay to hold the power on. Yes you can have a relay that is both powered by mains and switching mains and the Bulgin will turn it on but how will you turn it off? I am unaware of a relay that senses a momentary switch to both turn on and off, and I have looked. I am referring to a mechanical relay with a hold circuit, the hold circuit will need to be made "open" to release the relay to turn off.

You could use a latching relay and use one of the poles to reverse the coil polarity each time it switches, but it's prone to bounce.

If you can, buy a latching version of that switch. It's rated for 5A @ 250V, which should be lots, and then you don't need to worry about circuits and all that nonsense. This is what I did with my B22.

 

[alwayshungry]

Thanks for the advice guys. I decided to go with a ε24 so I can use a momentary switch.