newbie seeking info about homemade ipod amplifier

[disti]

Hi!

I'm new to the world of audio amplifiers, and I discovered it while developing a project.

I'm developing an homemade iPod audio station. I already created schematics for IR remote controller, PC interface, and some minor features.
Now I need to build an amplifier. This led me to a plenity of questions.

* Which type of amplifier should I choose? (output power, technology)
* What is the relationship between power and weight/dimensions/dissipated heat of the power supplier?
* What about volume control?
* What about those really nice vu-meters on professional devices?
* How should I choose speakers?

I really don't know anything about audio processing, so I'll give you an idea of the result I'd like to obtain, hoping that someone here can give me some suggestions.

* My device should be "portable". That means that its dimensions shuld be of about 30x30x8 cm, and it shouldn't be too heavy.
* Its power should be enough to be heard inside a room.

I already found volume control unit (MAX5406 seems good!) and a suitable vu-meter (LM3915N from Philips).

Now I'd like to have some suggestions about the amplifier. Can anyone please help me with a link to some schematics?

Thank you very much!
Roberto

[Netlist]

Hard to tell but if portable is a must I'd have a look in the ClassD forum.

/Hugo

[disti]

I'll have a look at it. But, can you please tell me why?

It's due to dissipated heat? or dimension/weight of the power supplier?

I saw some schematiscs that use chip amplifiers (such as TFA9843AJ) that seemed quite small and had a good power output. This is the reason why I posted here.
Still, I can't evaluate them as I have no experience with amplifiers.

[Netlist]

Originally posted by disti
It's due to dissipated heat? or dimension/weight of the power supplier?

Both; ClassD is highly efficient and can be build the size of a credit card (without supply).
Unfortunately, that's about all I know about them, I'm more like an analogue man.
ClassA, as an example, is the least efficient, requiring massive power supplies and dissipating a lot of heat.
Not something you want if portable is needed.

/Hugo

[Gordy]

Hi Roberto,

You have good ambition, and much to learn. Start by reading through the threads on this forum and try not to rush things!

A chip-amp might be a good place to start, although Class D is also sensible. If you have not made an amp before you might want to buy a pre-made module and then add a basic power supply. For decent ready-made amp modules look at the Hypex: site
http://www.hypex.nl/

Regarding the MAX5406: it has many features and controls, however please remember that it is not the best of performers. For more information on basic preamplification have a look at the ESP site:
http://sound.westhost.com/projects.htm
http://sound.westhost.com/project88.htm

[robertvalk]

What about using a National LM1876 (2 times 20 Watt)
//
Small
Enough output power
Lots of information on the net (google for LM1876 or LM1875)
Low voltage (+22 -22 V => ie 80VA 18V toroid)

and two small fullrangedrivers. (Visaton FRS8-8)
//
Don't need much room
Cheap (€ 10,- each )
Lots of info on the web (try the fullrange driver section of DIYAudio!)
High quality sound

Note: I haven't tried either of these suggestions but based on reading tons of info on the net about DIY you might try something like this.

[disti]

Thanks to all of you!

I'm collecting info based on your suggestions, I'll let you know if I end up with something interesting!

Of course, any further suggestion/comment is really precious to me!

bye!


Roberto