ljoe1969 Posted February 22, 2008 Report Share Posted February 22, 2008 hi. i just built this preamp http://www.till.com/articles/GuitarPreamp/ and i have built a circuit for 2 led's to go behind my pickups on my les paul. the thing is i want to use the same 9v battery to run both circuits. i plan on using a stereo plug to have them turn on when i plug the guitar in. for the led circuit i am using 2 red led's from radio shack in series and 1 resistor of the proper rating. i just need to know how to combine the 2 circuits. thanks. Quote Link to comment Share on other sites More sharing options...
psw Posted February 22, 2008 Report Share Posted February 22, 2008 Ok... So, all you do is "chain" the two LED's together...the long of one lead to the short of the other. Now you connect the resistor to one end of the chain, say the long lead of the now pair, now connect the resistor to the +ve terminal of the circuit (battery in) and the -ve terminal to the other end...if it doesn't work, the chain is probably around the wrong way...the jack socket switch that turns on the circuit will turn on the lights also. This is a series connection, depending on the resistor to step down the voltage, you could run it it parallel, connect the two long LED leads and two short, connect the resistor to the long pair and that to the +ve and the other to the -ve...may be a bit brighter, but will draw more power also. Hope that helps... pete Quote Link to comment Share on other sites More sharing options...
ljoe1969 Posted February 23, 2008 Author Report Share Posted February 23, 2008 here is a link to a pic of what i want. hope this helps. http://www.picturehosting.com/images/ljoe1...erstogether.jpg what i want to do is combine these two circuits. is there anything special i need to do or just connect the positive leads from both to the positive of the battery and the negatives to the ground. thanks. Quote Link to comment Share on other sites More sharing options...
psw Posted February 23, 2008 Report Share Posted February 23, 2008 Yep...that's all you need do as long as the resistor is right for the 9 volt or whatever you are using, just substitue that battery in your drawing for the positive and negative on the circuit...right to go. LED's will only light one way, so perhaps test which side is positive and which negative...you won't harm them unless you put the whole 9 volts through them, so if they don't light, you probably have them back to front...easy to do... pete Quote Link to comment Share on other sites More sharing options...
Blackdog Posted February 26, 2008 Report Share Posted February 26, 2008 ...or just connect the positive leads from both to the positive of the battery and the negatives to the ground. Yes. That's all you need to do. Connect the top resistor end to the +9V point of the preamp diagram and the bottom LED terminal to ground. Quote Link to comment Share on other sites More sharing options...
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