Is this safe for OPA2134?

[Thunau]

I built a 3 way crossover using ESP boards. I'm using OPA2134s. They have a rather nasty way of powering down, by dumping a sizeable near DC swing on the outputs. I was going to install a normally closed relay across the signal and ground on the outputs and power it from the 5V output of my switching PS. When I power up it will open the contacts and let the signal flow to the amp. When I power down it will close and the DC swing will dump to ground. Is it safe for the output buffer opams? There are 110 Ohm resistors on the outputs used to prevent oscilation.

 

[PMA]

Output short-circuit is unlimited in duration, but this is an overcurrent, not short circuit. Probably nothing wrong will happen, but ...
I would prefer NO contact with delayed ON function (NE555 timer e.g.).

 

[5th element]

?? Just powerdown your poweramps before you turn off the active. And visa versa, power up the active xover before the power amps. This is all I do and I avoid and nasties.

 

[Thunau]

That's what I have been doing all along, but it takes about 40 seconds for the caps in the amp to discharge when there is no music playing. I just wanted to make a more elegant solution than standing there waiting for the amp to power down before flipping the power switch on the crossover.

 

[tool49]

This might sound silly, but why not just always leave the crossover on? These thing should have a quiescent current of a few mA at a few volts... not likely to get your electricity bill any higher....

Or perhaps use a relay on the amps to shut them off as soon as you remove power from them.

Sébastien

 

[mskeete]

Use a relay as you first suggested but changed the output resistors to 680 ohms

 

[Vix]

I had the same problem. I solved it in a "silly way". I leave the crossover powered on all the time, except when I leave home for longer periods. Since the transformer is small, I don't think it will make a difference on your electricity bill
Regards
Vix