What is the easiest way to integrate a 12v trigger to turn on and off an amp? Suppose I am using 2 12v relays for a soft start and speaker protection circuit, I would imagine I need a 24v transformer. I've seen a number of ways to do soft starting and haven't looked at all the different ways of doing DC protection. Is there an IC that can sense DC and active relays using the same relay for DC sensing "nodes" for speaker protection and monitoring for on/off commands by an external unit?
uPC1237 used for speaker protection.
You could use a pin 1 + input to drop speaker relays and at the same time drive a slave relay that drops a heavy line contactor [not a relay] that shuts down all mains supply to all but the master control device.
Probably best to latch off on speaker cutout by use of pin 3 coupled to Ground via a cap rather than directly to Ground.
You may drive an additional relay from the uPC1237 [80mA] but you won't be able to drive a contactor directly..... coils being best at your supply voltage.
Would need a hard wired start/latch-on logic to power up all until speaker protection delay was timed out during startup.
Thing is, the trigger source would be the Amp?
Yes.... Then why not just use the trigger output from Amp to drive a relay/contactor to shutdown or power up all other devices rather than complicate by adding speaker protection output as well ?
You could use a pin 1 + input to drop speaker relays and at the same time drive a slave relay that drops a heavy line contactor [not a relay] that shuts down all mains supply to all but the master control device.
Probably best to latch off on speaker cutout by use of pin 3 coupled to Ground via a cap rather than directly to Ground.
You may drive an additional relay from the uPC1237 [80mA] but you won't be able to drive a contactor directly..... coils being best at your supply voltage.
Would need a hard wired start/latch-on logic to power up all until speaker protection delay was timed out during startup.
Thing is, the trigger source would be the Amp?
Yes.... Then why not just use the trigger output from Amp to drive a relay/contactor to shutdown or power up all other devices rather than complicate by adding speaker protection output as well ?
24V not needed if small relays are parallel connected rather than series.
or if relay driven by soft start logic is a 4 pole you use that to switch 3x dedicated 12V slave relays for 1) soft start [Amp DC rail voltage], 2) speaker protect [amp audio output] AND 3) mains supply contactor coil [mains voltage] for all peripheral equipment like tuner, Dvd, CD, tape, etc etc.....
IT would be very unwise / unsafe to switch all these different voltages in one single relay..... this is in the field of mains voltage switching
Why do you want or need to do this?
Always easier to work out control logic and explain by drawing up a 'truth table', showing input actions, time delays, and high/low logic output results.
The 'high/low' can be at CMOS, TTL or hard wired relay level at ELV [extra low voltage], LV [110 - 240V AC] or HV [high voltage > 600V].... doesn't matter. What does is the logic.
What does matter is the switch function logic to help design and fault find the circuit.
I suppose you could use the uPC1237 to time out the soft start switch logic - increase or decrease the time delay of primary resistance bypass by RC changes around pin 7 & 8 on the uPC1237.
That makes the speaker protection circuit the principal control over speaker connection and soft start function.
Simple is best.
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Why do you want or need to do this?
Always easier to work out control logic and explain by drawing up a 'truth table', showing input actions, time delays, and high/low logic output results.
The 'high/low' can be at CMOS, TTL or hard wired relay level at ELV [extra low voltage], LV [110 - 240V AC] or HV [high voltage > 600V].... doesn't matter. What does is the logic.
What does matter is the switch function logic to help design and fault find the circuit.
I suppose you could use the uPC1237 to time out the soft start switch logic - increase or decrease the time delay of primary resistance bypass by RC changes around pin 7 & 8 on the uPC1237.
That makes the speaker protection circuit the principal control over speaker connection and soft start function.
Simple is best.
Because that with thermistors and MOSFETs is all I can understand and find
started a microcontroller one over a year ago and still not done with it. Hey bud, hope all is well if you get to it you get to it. Some preamps and receivers have a 12v trigger output that use a 1/8th headphone jack to send a 12v DC signal to turn on and off other equipment. figured there was some IC that can sense some levels of DC and toggle the power at the mains.
Yeah, my main Amp [Yamaha 7.1] has this but I haven't bothered with it, preferring to use the switched mains outlet for the only peripheral gear [Blu-Ray] for shutdown. The only other item currently used is a TV but that's shutdown via it's own remote.
A home built Amp is easy enough to incorporate switche outlets using main switch [mains switching to main transformer] or using that supply rail to switch a power relay/contactor. Easy enough but a matter of safe practice given the 'kill ya' potential.
Regarding switching more equipment via Main Amp [only one switched outlet that is current limited] what I'd planned to do was use this switched outlet on Amp to trigger a power relay in a power board type arrangement. Easy to find a small 240V 1pole 10A relay] that would fit in there.
That way power board has two plugleads, one for supply with A,N & E 3 pin plug and second for control that has 2 pin plug..... the only configuration at back of Amp. No serious conflict with mixed voltage levels, and leaving the Amp's speaker protection/overload/DC clipping/thermal shutdown protection system limited to action on the Amp alone, rather than shutdown every device downstream.
You mention DC detection... that's inherent in the uPC1237 chip but again, thermistor triggered input to pin 1 on this chip could also be used to switch speakers out... the pin 1 could be used for a number of fault trip uses I suppose.
Most of the pre-built speaker protection boards you see on eBay don't use the pin 1 or have it grounded. Some have a too small relay rating for high output Amps too. Easy enough circuit to build your own Speaker protection board using the C1237, so no need to be limited by pre-built design.
I ordered a PCB completed that has the softstart, speaker protection and a number of DC sensing connections to trigger the relays. I should have it in another week or two and will see how the designer did it. I haven't used a lot of 12v triggers in the past but need to implement them for my setup I am working on now. The LCR speakers are actively crossed so that's 9 amps right there...plus the subs, surround and Atmos speakers...I would be pressing power buttons for 20 mins without.
Did you get it, did it work and have a link? (yes I know this is an old thread but I need the same thing.)
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