| BubbaGump |
I am really new at this, and having never built an audio amp, I really need help. I am trying to create a stereo audio amplifier with an output power of close to 4W per channel. The speakers I am using are the CMSO321KLX
If anyone can just flat out tell me what IC to use and give me the design (or where I can buy a kit), I could finally figure out how to build an amp. I really just need a good amp to build with my hands and I will learn a lot more than just reading about stuff. Thanks. |
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| jaybombalous |
| Don't some pre-amp's have 20 watts a channel? |
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| owen |
The Sonic Impact T amp fits this remit like a glove...
Owen |
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| Boris_The_Blade |
| An LM1875T or LM675T would be a good beginner's part. There are various kits around...do a search and I'm sure you'll find something. They are rated for higher power, but just a wimpier supply would be OK for your power levels. |
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| BubbaGump |
| Yeah those would probably be ok, but it looks like its only one channel (mono). I need it to supply power to 2 speakers, (stereo.) can anyone give me any other options? |
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| Nordic |
| If people can fit two LM3875 circuits plus sinks in a PC power supply box, so can you.... |
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| Boris_The_Blade |
This would do ya fine...
http://www.electronics123.com/s.nl/...c=8&category=33
Just remember to pick up a 12VDC wallwart supply that gives 12vdc at least an amp. Preferable 1.5 amps. A switching supply would be good here since they are lightweight. You'll have to cut the connector off the end to hook it up to the kit. Remember or write down the polarity. |
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| Nordic |
A kit is great as a second build, but figuring out and pieceing together that first litlle screamer, is a job you should do yourself.
Building a circuit will give your more familiarity with the many concepts out there, in a physical tangible way... I have built complete kits without even looking ath the scematic... just plugging parts into the silkscreen....saved a few bucks from buying the complete item, but learned nothing!
You just have to follow the simple pre thread, to see how even the smallest bits of information on customs and conventions found in the real world, like which way around to hold an IC to number the pins, can be daunting, but will be lifelong skills once learned, but crippleing until.
I suggest you goole Datasheet LM1875 to get a datasheet on the chip, and a suggested schematic... make a list of parts, buy them, lay them out to accommodate their physical sizes (later you will learn to order the size you want).
Then come back and we will show you how to filter out the frequencies below what those speakers can handle... saves your amp/batteries alot of work keeps the speakers happy, and improves sonics by haveing to cover a smaller bandwith.
I think the average Lego kit for 10 year olds, is more complicated to build, it just exludes the opportunities for burning your fingers on a hot iron...WHICH YOU WILL DO! ....at least a few times |
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| v-bro |
| quote: | Originally posted by Nordic
A kit is great as a second build, but figuring out and pieceing together that first litlle screamer, is a job you should do yourself.
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I think it depends on whether you want to learn or just want an amp...
I actually learned a lot from building kits, it just depends on how inquisitive you are.... |
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| Nordic |
Absolutley on both accounts, its just some kits consists of many subcircuits (even something like the highpass on an input as an example), not to mention the complexity you reach with some of my other projects the like the inductor and capacitor meter... where it gets more likely you just shut down and build, if given in kit form.
I think for probably 5 dollars in components it might just be worth it to give it a shot...provided you have a soldering iron, reading his post it does seem like he would accept a kit, but also seem keen to learn... You could probably try 3 topologies for the price of a kit, or buy the needed transformer etc... there is always a payoff to the manual route... |
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| BubbaGump |
| So you're saying I should just go ahead and get the parts for the recommended mono schematic, then reply back and people will help me build it? Then I will have a little more info on audio amps and can possibly build a 2 channel amp? Also, my amp needs to run on a 9V battery. |
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| BubbaGump |
| More questions. The datasheet for LM1875 has two different typical applications (pg. 1 and 2), a schematic diagram (pg. 5), and the component layouts for split supply and single supply (pg.8). Which one of these layouts do I use to determine the parts that I need to buy? |
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| Boris_The_Blade |
The more you get into building an amp from scratch, the more complicated it becomes. For example, with he LM1875, you'll end up needing to get the following:
discrete components
-the chip amps
-caps
-resistors
-diodes
hardware
-heatsink
-protoboard
-screws
powers supply parts
-extension cord (to cut off end)
-power transformer
-bridge rectifiers
-supply caps
notes:
just remember the no-load voltage can be a good deal higher than the rated output voltage @ a given current. The chip-amp must be able to withstand this voltage and the heatsink must be able to dissipate the additional heat from the increased supply voltage.
point being:...
it can be quite a task to design an amp, and there are things that you'll learn after going through it and playing around with the electronics parts for a while. To make sure you'll get a successful amp when all is said and done, the best route is a kit. It is how I learned the do's and dont's of electronics (look at my website for where I'm at now:-) The kits will illustrate what a typical design will be. They usually always come with schematics that will show how they operate.
If this is your first build, buying all the parts and doing it correctly will likely result in a lot of headaches and a long time before you getting it to make music. It is up to you, but the kits are there for your help (and they are pretty cheap too :-) |
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