Go Down

Topic: 3 watt audio amp (Read 836 times) previous topic - next topic

ScottG

I am building an alarm clock and for the sound I'm using Sparkfun breakout board for a WTV020SD.  It has a built in 1/2 watt 8 ohm amp, but I am thinking of using an external amp.  The breakout board has a dedicated 16-bit DAC/PWM audio output to use with an external amplifier.  My speaker is just a little 3W 4 ohm - Digikey 668-1234-ND.  I'm thinking of using either an ISSI IS31AP2005 or Analog Devices SSM2305 audio amplifier.  They seem to be the same thing to me, except ISSI is about $0.35, Analog Devices is $1.55.  Is this a good choice for my application?  In the example circuit (attached) from the data sheet's I wasn't sure how I should control the volume (I can't do it with the WTV020SD breakout board).  Would I put an audio potentiometer in for Rext?  If so, do I need  dual gang one?  I'd like to just have a little trimmer pot for the volume.

cjdelphi

In the real world, better the speaker, better the quality...

For example, i happily drive a 20watt (generic) satellite speaker from a 5.1 setup and avoid all the little cheapy speakers, those speakers are generally heaps better sounding regardless of your driver it's just a thought, I use a cheap amplifier with a decent speaker rather than a cheap speaker (they sound tinny)

But you know if you don't mind the power loss you can build a Class A? (the crappiest of all of them) using a half decent power transistor and 3 resistors practically but is a waste, it's better to amplify it in stages and give a feed back , but literally a tip31 a voltage divider gives a killer amplifier circuit if you don't mind wasting the power that is....

cjdelphi

"Would I put an audio potentiometer in for Rext?"

Sure, a 1 - 5k? potentiometer, it should not matter be it before or after the filtering cap (to block DC)

ScottG


In the real world, better the speaker, better the quality...

For example, i happily drive a 20watt (generic) satellite speaker from a 5.1 setup and avoid all the little cheapy speakers, those speakers are generally heaps better sounding regardless of your driver it's just a thought, I use a cheap amplifier with a decent speaker rather than a cheap speaker (they sound tinny)

But you know if you don't mind the power loss you can build a Class A? (the crappiest of all of them) using a half decent power transistor and 3 resistors practically but is a waste, it's better to amplify it in stages and give a feed back , but literally a tip31 a voltage divider gives a killer amplifier circuit if you don't mind wasting the power that is....


The alarm clock will be in a Doctor Who Tardis (my daughter is a big fan); so I don't have much room for a speaker. Sound quality for this project isn't very important. 


Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy