looking for low watt stereo amp

[beatnik]

Hi fellas,

I am asking suggestion for a little project.

I have two small Aiwa speakers for iPod/laptop use. They are self powered but the amp got broken in some way and now only one channel works.

I would like to build a new amp rather than debugging.

The speakers are 3 ohm impedance and the original power amp has 1.5 + 1.5 W power.

Do you know any little useful project?

Thanks in advance

[jubal81]

I'd suggest a Class D amp. Easy, sound good, low power. Plenty out there.
Here's a project for one from good ol' Dano:
http://beavishifi.com/projects/class_d_amplifier/

[jubal81]

Actually, this looks like it might be just what you're looking for:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-306

[beatnik]

Thanks a lot, they seem to be very cool projects, but..... I am a diyer! I really would like to build it from scratch. Now looking for schematics, if you know something just tell me. Thanks again

[petemoore]

  1 Power Supply
  2 A Chipamp ? TDA2030, LM3886...the amps like an addendum circuit to the power supply, but the chassis and heat sink are...what they are...sometimes a bit dangercult to build/layout nicely.

[DavenPaget]

Hi fellas,

I am asking suggestion for a little project.

I have two small Aiwa speakers for iPod/laptop use. They are self powered but the amp got broken in some way and now only one channel works.

I would like to build a new amp rather than debugging.

The speakers are 3 ohm impedance and the original power amp has 1.5 + 1.5 W power.

Do you know any little useful project?

Thanks in advance

a TBA820M based circuit . ( 12v will provide 2W , so be careful , use 9V )

[therecordingart]

I started a thread it the OT section about analogmetric.com.

http://www.diystompboxes.com/smfforum/index.php?topic=94312.0

[beatnik]

thanks guys for the tips.

I've found many interesting little circuits on this page, i think I'll give a go to the tda2005.

Let me know what you think about it.

http://electroschematics.com/1192/tda-amplifier-circuits/

[Gurner]

I'd nominate a TDA7053A  (pin for DC volume control, very low parts count) ...3 ohms is a bit of a nasty load...be sure to heatsink whatever IC you use.


Edit: Actually scrub that, you'd be better off going with single ended amp IC .....3 ohms is far too low for a BTL IC (which is what the TDA7053a is)

[DavenPaget]

thanks guys for the tips.

I've found many interesting little circuits on this page, i think I'll give a go to the tda2005.

Let me know what you think about it.

http://electroschematics.com/1192/tda-amplifier-circuits/

TDA2005 does 20W O_O
That would blow 'em up .
Just use a TBA820M based dual chip circuit , 1 for left 1 for right , i have 2 of those amps at home for benching speakers

[Gurner]

TDA2005 does 20W O_O
That would blow 'em up .

That's not how it works ....output power is derived from supply voltage (which in turn dictates the largest signal voltage swing you can therefore expect out of a given audio amp IC), whether the amp is BTL or single ended and finally the load impedance. So, if the supply voltage is 5V and the load 3 ohms, then you'll not be able to get anywhere near 20W. An analogy being, if I owned a Ferrari, I don't have to drive at 220mph to the corner shop (though that'd be fun!) ....it'll go at whetever speed I ask of it......same with an audio amp IC.

The 20W figure here merely means the amp IC is capable of disapating the associated heat generated if it was required to deliver 20W ....it'll deliver whatever is required of it  ....1W, 2W etc - like I say, that's down to the supply voltage an load.

[petemoore]

  Got one in a nice case, was RTPerform OOTBOx, perform it does too.
  1^ providing the Power Supply is connected/adequate, bought one of those too, I like having 5amps of 13.8V regulated power available anyway.
  The chipamps chips I've worked with and set to various applications are all very good or better IME, haven't tried that particular one, but would look for verified layouts for match to whatever chip is chosen, 'it' is all in the layout, grounding and power supply [voicing etc.]. Power Supply, heat sinking and chassis are the 'hard part', the Mosfet Amp I bought for less than I could build one for does look nice, and is compact.

[DavenPaget]

TDA2005 does 20W O_O
That would blow 'em up .

That's not how it works ....output power is derived from supply voltage (which in turn dictates the largest signal voltage swing you can therefore expect out of a given audio amp IC), whether the amp is BTL or single ended and finally the load impedance. So, if the supply voltage is 5V and the load 3 ohms, then you'll not be able to get anywhere near 20W. An analogy being, if I owned a Ferrari, I don't have to drive at 220mph to the corner shop (though that'd be fun!) ....it'll go at whetever speed I ask of it......same with an audio amp IC.

The 20W figure here merely means the amp IC is capable of disapating the associated heat generated if it was required to deliver 20W ....it'll deliver whatever is required of it  ....1W, 2W etc - like I say, that's down to the supply voltage an load.

Read the sheets , it says 20Wrms @ below 18Vmax ( let's presume 15VDC normal ) ,
Wait , let's look at it again , it says 19Wrms @ 15V ( let's say ) @ 3Ω , how about 5VDC ? ( 15V @ 3Ω puts out around 4V/5A according to I=V/R ) but that's not what the amp is normally supplying , it can't be anyway ,  Drop the supply voltage to 5 ? 4V ( divide by 3 first ) * 1.667 gives around 2.27W , that's still over 1.5W

[rogerray]

I have a desktop tube amp and I believe you can't effort not having one. I bought it from a guy on diyaudio forum at $150. But now he don't sell it any more.
You can also buy it here:
Miniture 6F3 2.5Wx2 tube amplifier
My amp is black, really nice small gadget. It seems that they don't sell black any more, only gray and silver.

[DavenPaget]

I have a desktop tube amp and I believe you can't effort not having one. I bought it from a guy on diyaudio forum at $150. But now he don't sell it any more.
You can also buy it here:
Miniture 6F3 2.5Wx2 tube amplifier
My amp is black, really nice small gadget. It seems that they don't sell black any more, only gray and silver.

He is asking for a little project , not a always gargatuan tube amp .

[tca]

Do you know any little useful project?

Just build two of these (one for each channel): The Bulbamp: 1 Watt guitar class A amplifier with a light bulb

http://www.diystompboxes.com/smfforum/index.php?topic=94224.msg812138#msg812138

[Gurner]

Read the sheets , it says 20Wrms @ below 18Vmax ( let's presume 15VDC normal ) ,
Wait , let's look at it again , it says 19Wrms @ 15V ( let's say ) @ 3Ω , how about 5VDC ? ( 15V @ 3Ω puts out around 4V/5A according to I=V/R ) but that's not what the amp is normally supplying , it can't be anyway ,  Drop the supply voltage to 5 ? 4V ( divide by 3 first ) * 1.667 gives around 2.27W , that's still over 1.5W

I'm not understanding your text.

At 5V supply voltage to an audio IC amp, the best you could really expect out of it into the load is something like 4.2V peak to peak...that's  1.485V RMS which into 3 Ohms  = 495mA  which works out at 730mW.

I still don't think you're getting the main cut/thrust ...the quoted 'wattage' of any IC amp does not mean much other than its capability/capacity to dissapate heat.....so  beatnik can quite readily use a TDA2005 "20W capable" amp IC without any fear of "blowing" his small speakers. (assuming he doesn't go crazy with the supply voltage)....at a supply of about 9V, reckon on a max signal 'peak to peak' of about 8V, which into 3 ohms is about 2.6W, so he should really limit his power amp IC's supply voltage to about 7V to keep the max power into the load at around 1.6W max (i'd probably go with 6V supply voltage to err on the side of caution)

[petemoore]

  Chipamp.com provides a rich environment for observing and learning.

[Nasse]

Quite good bargain is lepai tripath amp from ebay, catch them if you can, maybe discontinued

[Renegadrian]

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