Amp Delay Turn On Solution?

**thenick100** · 01-27-2006, 09:21 AM

Right, I have that problem where im using an external soundcard, so i get a BIG pop when i turn on my carputer and know this is because my amp is turning on before the sound card loads up, so i need to delay the amp turn on until windows is running. Ive searched around and found various methods of doing this:

- using a program to generate a signal on the serial port and using a transistor turn on the amps

- using a david navone amp delay device

- using a switch

Which is the best way? I live in england, so getting the david navone thing would be expensive... Suppose i could build one if someone told me how? The serial port looks quite good, but fiddley and i cant get the program, and dont really want to use a switch!

Suggestions?!

Thanks, Nick

**MartyM** · 01-27-2006, 01:47 PM

Yes, I have a suggestion. You could build a little (and inexpensive) 555 timer IC-based circuit, and it would allow you to have some control over the time delay also.

You should be able to fairly easily do a web search and find a "555 timer delay" search result for the circuit or similar.

Very common IC. I mean, it might be overkill to use a serial-port based device.

If you don't find it let me know as I still have an old Radio Shack 555 timer design mini-book at home.

**thenick100** · 01-27-2006, 02:03 PM

thanks for your suggestion! Sounds perfect, ive looked around google and found several diagrams for it but no basic explanations.. They all seem to have too many inputs and outputs such as discharge/threshold/control voltage - what does it all mean and how does it work? I have only limited experience with breadboard stuff so find it a bit confusing!

**MartyM** · 01-27-2006, 02:59 PM

Well, I wonder if you were looking at the data sheets of the 555?

You will need a simple circuit diagram instead of that. One of those will show you just some (generally) simple supply voltage, ground, and output, etc.

Those details you mentioned are used in various ways to control the function of the chip and determine time parameters. But really just find a good complete schematic and you will only need to worry about resistors and cap. values. The rest of the details will just be connections, really.

Otherwise, let me know and I'll find an example.

**thenick100** · 01-27-2006, 04:01 PM

Hey sorry to be a bother! but i cant find anything but complex circuit diagrams, mostly designed to flip flop a pair of leds! have you got a link to a decent one? Thanks

**MartyM** · 01-27-2006, 04:14 PM

Hi, here are some. I had forgotten about this one, and it's for 12V applied: (non-555 based)

http://ourworld.compuserve.com/homep....htm#delay.gif

Here's one with the 555, it mentions a computer as the switching source, and parts list! 9V supply but you can change that...

http://www.aaroncake.net/circuits/relaytim2.htm

Have fun.

**XxAndyxX** · 01-27-2006, 04:48 PM

DEI makes a timing relay if you don't want to build your own.

Using the serial port will be the best way to go though.

**thenick100** · 01-27-2006, 08:05 PM

Cool thanks guys.. does anyone have a copy of that serial port program? there was a link on the forum somewhere but it was dead. I think ill give both a go and see which is gonna work best!