just starting =)

[Chrabban]

Hello Everyone.
i am new here. later on i want to be abel to buld a amp from scratch . i saw the BPA300 build (DIY BPA300 6x LM3886 300W audio Amplifier) and i think that that turn out awsome. i want to do something like that later on. right now i just want to start out small. i have found some kits on Ebay. that i wanted to ask you all about with one to take and if i am missing annything i dont know if i want to make 2 separat mono amps or a 2ch amp.

from DIYaudiokit

first kit: LM3886 LM3886TF 68W Power Amplifier S2 Kit (Stereo) | eBay

and one or two Toroid Toroidal Power Transformer T140 0-20-24-27V 5A | eBay
it says that i shold have 2 but is that only if i am going to use it in to cases or will i need 2? will i need some more capacitor? and is the speaker protection something that is good to have or shold i just skip it ? if i can skipp it then there is kit 2

kit 2: 2x LM3886 LM3886TF 68W Power Amplifier Mono Kit | eBay

and one or two? DC Power Supply 0-30V (5A) DIY kit (1 Channel) | eBay

and some capacitor? if i need more of them can you tell me if there is some good ones on the same stor so i dont need to ship them from somewhere ells


from gigawork: i cant find everything that i need for a complete amp but i might be blind

kit 1: LM3886 High End Power Amp Refer Gaincard New | eBay

kit2: UK POWER AMP KITS W POWER SUPPLY REFER NAP140 NAP-140 | eBay

HiFiSpot also seames to be okey but i have a hard time putting eferything together :/

i live in sweden so if there is a plase in EU with the same stuf to the same price i can get it from there :P i realy hope that some one will help me in all this thanks a lot

[hurtz]

Hi, if you want to build a chip-amp from scratch, I suggest starting reading the datasheet of the chip you want to use (lm3886?). In there you will find useful information on power needs/output, a sample circuit (read the lm4780 datasheet it has better description), and also the application notes which should give you a good idea what parts are for what. After that, you can start discussing the layout and grounding schemes!

cheers!

P.s. I think the toroidal is hugely over-priced should be half of it.

[Chrabban]

Is it Hard to make one from scratch? How long dose it usually take to make one for à complet beginner ? if i dont have à pcb but want to try it before i make send after some pcb's, is there some kind of test plate i can use?

Is ennything of what i found (first post) good or is it just expensive and bad?

[hurtz]

Well it depends on your prior knowledge. And what you mean by building!
If you "just" want to build one, all you need is some experience with a soldering iron, knowing how parts like resistor, capacitor, transistor and then an opamp (operational amplifier) is basically working. It is also most useful to have a good understanding of the difference between voltage and current. And last but not least, to read a circuit diagram!
This way you are "blindly" building it, if you follow the schematic exactly you can basically build any amp(thing). But keep in mind that it can be quite annoying since without knowing what is doing what you can't identify errors by yourself.

If I may assume that you are a beginner in electronics, I'd suggest two things: First, look through this forum in the vendor/market section for a lm3886 kit (I believe chipamp.com is widely approved) This way you can get first-hand experience in soldering with a nice result you can touch and hear! (If this is your first time soldering you might want to practise on some resistors before you start with the temperature critic components)

The second thing is, you should find a local electronics part vendor. (less than 0.10€ per resistor is a good starting point) There you can also buy BCB's which have pre-drilled holes with small copper-platings around them. This will help with prototyping. I also suggest that you start with a smaller project, that is using the components in a more position-independent way. Audio-circuits are very sensible.

I started some time ago with the arduino microcontroller, which provides a nice way of experimenting with all different kinds of parts. Also I can recommend the arduino forum, where I think people will be more inclined to answer questions about general electronics than in the specific chipamp-section here ;-)


cheers!

[Chrabban]

i have some prior knowledge. in highschool (i think it is in english) i was in a 3year electrician education (low current) so i have some experience with a soldering iron ( i have one from Weller).

local electronics part vendor: is ELFA good? i dont know but they have alot
https://www.elfa.se/elfa3~eu_en/elfa...hop=ELFA_EU-EN

and in september i am going to a 1 year long education that is for circuits inside almost everything. we will get this one to play with Terasic - FPGA Main Boards - Cyclone IV - Altera DE2-115 Development and Education Board =D

i dont know what BCB is :/

what kind of smaller project? =)

[hurtz]

*PCB.. typo..

Well seems that you are all set to start with the datasheet. As mentioned earlier, read through the lm3886 datasheet and lm 4780 datasheet, and try to understand what every component does. To do some self-advertising, check out the "the yet tiniest lm3886.." thread, I started with some very basic amplifier knowledge and built a lm3886 PCB. There is a lot of discussion about the grounding and many other things too.

If you are looking for a smaller(i.e. simpler) project, you can either go for something discrete in the likes of "see a need fill a need" or play around with a microcontroller (which I find more interesting).

cheers!

[Chrabban]

i will read the tatasheet and se if i understand did you say that the lm4780 datasheet was better? u have seen it, i hope that it will be a great amp =) i might just buy a kit from you when you have them what is the total cost of one kit? if you know that yet?

how mutch did you know about amp building when you started ? :P

[Chrabban]

now i have tried to understand the datasheet...... there is just so mutch, i dont know if i can understand all this :/ it might be simpel but all this text makes it look hard :P how hard is it ? :P

[hurtz]

I can tell so far that all the parts included in a single PSU+ and two AMP-PCBs with 80VA 18V toroidal is about 60€.

Not very much, I had built the symasym before but I can't say I understand all of the circutry.

If you read the datasheet, analyse one group of components at the time. For example start with the capacitors and resistors at the input, power rails, feedback, etc.

On the subject of how hard it is, nothing worth knowing comes easy ;-)

cheers

[gerben00]

Just finished my first amp based on an lm1875, and the thing sounds beautiful! How i started out is first figuring out the circuit on a breadboard; i know some people say this can