What IC should I use?

[CorySCline]

Hello all! Just looking for advice here. I have successfully completed a 1W amp based of LM386N-4 and played with it a bit to modiy gain, etc to learn what I could. I would LIKE to make an amp that I can use at gigs, etc. However, the learning experience has been almost nightmarish with SEVERAL path changes and not knowing where to go. So, I will ask a simple question (and expect complex answers as they just come with the territory). What IC should I look into to start building this project? I was something that has a wide bandwidth and fidelity. I also want it to be lou.d Mind you, this may dreaming, but I picture a 4X12 speaker cabinet....or 2....lol. And this dreaming is what's holding me back. I keep getting too complicated for my own good. I need something that uses 110V main to power it. Or....possibly a tutorial on designing power supplies to step main power down to needed voltages...

Forgive the rambling, but my wishes are beyond my knowledge and it's frustrating (As I'm sure you unerstand and have at some point experienced.)

[Francec]

Read some of these to get an understanding so you know which questions you need to ask.

DIY Audio Articles

Frank

[AndrewT]

Read Decibel Dungeon.
Read the datasheets and the application notes issued by National.

[qusp]

I second the reading of the natsemi app notes, excellent and very thorough, plus i believe they are currently the best driver chips available

[CorySCline]

I am all for pouring over datasheets . However, What I am trying to get a grasp of, what numbers should I aim for? What voltages, output wattages, etc will be a "safe amount" for a beginner to work with? Not being a specialist in this field (yet?), It's like me trying to pick a car having time travelled from 1492....lol

[Francec]

It's like me trying to pick a car having time travelled from 1492

Yes, a very good analogy except I would use it differently. It would be more like you trying to drive a car having travelled from 1492 when you have no idea what the road rules are. In which case, I'll say goodbye now because you won't be alive much longer if you aren't prepared to read some things that will SAVE your life, such as about proper wiring, earthing and to use mains voltage.

Electrocution

Having said that, I use three LM3886 amps per box in an active three way, with active crossover, speaker protectors, transformer, power supplies (yes, two - one for +-15V), and balanced driver for bridging the woofer amp all in the bottom of the cabinet.

But it is pointless you knowing all that because you won't have learnt enough about the dangers of using electricity. R.I.P.

Frank

[CorySCline]

Originally Posted by Francec

Yes, a very good analogy except I would use it differently. It would be more like you trying to drive a car having travelled from 1492 when you have no idea what the road rules are. In which case, I'll say goodbye now because you won't be alive much longer if you aren't prepared to read some things that will SAVE your life, such as about proper wiring, earthing and to use mains voltage.

Electrocution

Having said that, I use three LM3886 amps per box in an active three way, with active crossover, speaker protectors, transformer, power supplies (yes, two - one for +-15V), and balanced driver for bridging the woofer amp all in the bottom of the cabinet.

But it is pointless you knowing all that because you won't have learnt enough about the dangers of using electricity. R.I.P.

Frank

All the warnings are great. however, the way it comes across is that you seem to think I disregard safety. Quite the opposite is true. I am WAY overcautious. This is why I ask the questions I do. I would gladly take a college course if I could afford it. ALL I'm really asking for is a way to LEARN the safe way to do these things. Notice I said the safe way. I dont want a "tutorial" that says plug this here, and that there. I want to know the theory of it all. I want to be able to recognize that what I'm about to do is dangerous AND why. I do not proceed with any builds until I am POSITIVE that I can do it safely, and even then I will proceed slowly and excessively carefully with attention to every little detail. I get that you have to be cautionary the way that you are. HV is dangerous. NO one is immune. The idiots that think they are die. That is understood by me. I do not intend this message as anything more than "I get that I need to be careful. I will. where do I go from here?" If anyone is offended by this, I apologize.

[nigelwright7557]

Class AB chip amps probably wont be loud enough for you.
Go for a discrete class AB design of 500 watts plus.
Go for a design off DIYAUDIO as there are some internet designs that just dont work.

[Francec]

Nigel,
The guy is a beginner and you want to set him loose on supply rails that would kill an elephant?

OK, Cory, understood. What "gigs" are you talking about so we have an idea of what you are driving and do you have a speaker at the moment or is that part of the grand plan?

Frank

[!]

Cory, you're wanting to build an amp running off 110V - any of them are potentially exposing you to lethal voltages. You're wanting enough power to drive speakers fairly loud, any amp capable will have power rails with high enough voltage to cause harm.

There isn't a lot to say about safety except the things which are obvious, don't go touching live circuits, shorting things with metal tools, or powering up a design without inspecting/double-checking it, and ideally do not work on such projects when tired, late at night, etc when mistakes are more likely to be made. In the end, you power it up and stand back hoping it doesn't make snap crackle pop boom type sounds.

You mention "IC" but you're probably wanting not a single chip solution but rather a driver IC like LM4702 LM4702 - Stereo High Fidelity 200 Volt Driver with Mute for your dream project, but how about an intermediary project for more amp building experience first, like a basic gainclone using same parts other amp builders are using?