TL-082

Hi Buddy,

You don't need anything for a TLO82 (or 72) specifically. It is about as bog standard an op amp as there is (though I will say in passing that I have an affection for it and that it is used in some great pieces of equipment). Blu_glo asks perhaps the only possible questions, and the answers are pretty much applicable to any FET op amp (the FET part only making things easier).

The best advice I can give you short of a tutorial is to read or download Walt Jung's op amp handbook. You will be amazed at how much progress you make and how quickly! You can get it from his website or from Analog.com.

In short, though, for a buffer, you just need a short from output to -ve input and an impedance seen by the input of whatever is needed. That goes to ground because the +ve input has nominally infinite resistance once connected up this way. A small resistance into the input afterwards is sometimes a good idea - 50R but not usually needed. For an inverting buffer, you need the same resistance as the input in place of the short and then have an equal resistance to the impedance you want going into the inverting input (-ve), and have a short from +ve to ground. You may read about balancing the impedances seen by each side, for both topologies, and you may confidently ignore that advice.

I would do you a circuit but I'm on a Mac and firing up Windows to get onto LTspice isn't necessarily going to get this to you any quicker. Download LTspice BTW. It's the best free thing in the world.
 
I have the tone control problem solved...now I need a buffer circuit that will give a pre out of at least 4v... Anyone got one ? I really appreciate your help... (Tl082) :)

So everyone is on the same page, are you talking 4 Vrms or 4Vp-p? What is the signal level coming in to the buffer I.E. how much gain do you need? Do you need 'headroom' over the top of your 4 Volts and if so, how much? You won't get realistic answers until we know what you expect. Don't feel bad if you can't specify exactly yet. Most projects 'evolve'.

 
Stratus 46 thanks for the reply ...Im running signal from a B110 Dell Tower with no tone control function. out of that Im running into a Sony Car Tuner deck , then into 4 separate Bose power amp modules. (From a 90s something Acura) Sounds real good except Im not getting full volume . I figure if I boost the signal with a buffer amp I can get the full volume... I have 2 Tl082s and I have 1 lm324 , Im not privvy at all with theory but I am pretty good at building simple circuits from schematics ...I also need to know how to take the reading on the output (rca) off the Sony , The sound is crystal clear with no audible distortion , just need a scunch more output . I hope I explained clearly what I need to accomplish... Ive been a mobile electronics tech since 1982 , and dabble with OEM stuff ...I built a dual 12+ 12- supply using 7812 and 7912 regulators to run the pre amp circuits so I have 1 ampere current capability. thx for the knowledge :)
 
OK, you don't want to use an LM324 for audio. It's dreadfully slow. They're OK for some uses but not good for audio. For you 'booster amp' I'd first start with a simple 6dB (gain of 2) amp. Do you have dual (+ & -) supplies or is this a single 12 Volt supply? It's a little more complicated with a single supply but your LM324 might be a good 1/2 power supply reference. More info needed.