STUPID QUESTION :how to add a signal present led ?

i need to add a signal led in a small headphones amp i´m building, how to do it? the input is unbalanced.

Thanks

Bump

c´mon! that´s why i said "STUPID QUESTION" !!! it might be the simplest thing in the world but still have doubts on how to do it

anyone?

It sounded like you knew something about metering from your previous post.

Anyway, heres a couple of ideas

http://hem.bredband.net/bersyn/Signalindikator%20W.gif

http://1176neve.tripod.com/id12.html
Just use one LED

Peter

[quote author="Silvas"]c´mon! that´s why i said "STUPID QUESTION" !!! it might be the simplest thing in the world but still have doubts on how to do it[/quote]
It isn't a stupid question, but it is a stupid thread :wink: :thumb:

Such a question asked & covered various times before, for instance here:
http://www.groupdiy.com/index.php?topic=3708
and here
http://www.groupdiy.com/index.php?topic=4842

etc

Thanks !

sorry clint for posting what you call a stupid thread, but sometimes the search engine doesn´t give anything relevant (YES I SEARCHED!), so i guess this is a place where you can ask such a question....anyway, for a simple question, a simple answer will do i guess.

[quote author="Silvas"]Thanks !

sorry clint for posting what you call a stupid thread, but sometimes the search engine doesn´t give anything relevant (YES I SEARCHED!), so i guess this is a place where you can ask such a question....anyway, for a simple question, a simple answer will do i guess.[/quote]
No problem, I won't dare to state I haven't done an alike thing and/or won't ever again. And my re-use of 'stupid' hadn't be there if it hadn't been around here, so it was all in jest.

It is a bit of a FAQ though, the links I gave showed up with searching for stuff like 'LED', 'signal', etc. But I agree that while the search engine here is often adequate, it's certainly not the best.

OK, which circuit do you plan on using ? If it's not needed to catch both pos & neg sides of the signal it can be very easy. I myself would then go for something like this:


Signal enters at the top of R7. Adjust resistors for trigger-level.

Cheers,

Peter

THANKS !!!

in fact what i was looking for was something extremely simple, no need to catch both sides of the signal, i think the one you posted will be perfect.

it´s just a dual stereo headphone amp i´m building inside a fried firewire avid case. i need a couple more stereo cue mixes in one of the studio´s rooms so i just need to see if there is signal on the amps.