Audio amplifier shield with SD card slot

Hello !

I am looking for a an audio amplifier shield, arduino compatible and has SD card slot for 150watt, 4 Ohm passive speaker..i found some shields but have too low power around 20watt

any ideas ?

** will be great if someone has already used AMP shields with arduino to reply

Maybe buy something like this an mount it to a shield protoboard?

http://www.ebay.com/itm/YJ-IRS2092-200W-Class-D-Amp-Mono-Amplifier-Board/172368920006

pjrc:
Maybe buy something like this an mount it to a shield protoboard?

http://www.ebay.com/itm/YJ-IRS2092-200W-Class-D-Amp-Mono-Amplifier-Board/172368920006

thanks, looks nice but operating voltage is 30-60V and has no built-in SD slot so i will need another module plus another battery (i use a power bank with 12 - 16 - 19V outputs)

You’re not going to find such a thing. You’ll need a separate amplifier. And you’re gonna’ need more voltage!

FYI - A speaker rated for 150W doesn’t “need” 150W. That’s the maximum rating.* What’s the application? Do you need to go “super loud”?

Of course, your power supply has to supply the power. Power is calculated as Voltage x Current, so at 19V you’d need almost 8 Amps. Can your power supply deliver that?

And, current is Voltage/Resistance (or Voltage/Impedance)… Or, power = Voltage2/Impedance.

A “normal” single-ended amplifier powered from 19V can give you a theoretical maximum peak-to-peak voltage swing of 19V (in reality, less because there is voltage loss/drop across the amplifier). 19V peak-to-peak is 6.7V RMS. And, 6.7V across 4 Ohms works out to about 11 Watts. If you want more power you need more voltage! Note that high-power automotive amplifiers have an internal voltage booster to get higher power from 12V.

A bridge amplifier can deliver 4 times the power with the same voltage, so you can get about 40W from 19V.

  • Actually, it’s the “music power” rating. Normal audio has about a 10:1 peak-to-average ratio, so a 150W amplifier maxed-out (but undistorted) will be delivering an average of about 15W. If you run a constant 150W test-tone into a “150W” speaker, you’ll fry it! And, that’s assuming the specs are honest… Most “150W” speakers will probably fry with 15W constant!

DVDdoug:
FYI - A speaker rated for 150W doesn't "need" 150W. That's the maximum rating.* What's the application? Do you need to go "super loud"?

the application is hearing test, so i wasnt planning to run it at maximum rate, 40Watte @ 4 Ohm will be enough.

DVDdoug:
Of course, your power supply has to supply the power. Power is calculated as Voltage x Current, so at 19V you'd need almost 8 Amps. Can your power supply deliver that?

the power supply can deliver up to 26.000 mAh.

DVDdoug:
A "normal" single-ended amplifier powered from 19V can give you a theoretical maximum peak-to-peak voltage swing of 19V (in reality, less because there is voltage loss/drop across the amplifier). 19V peak-to-peak is 6.7V RMS. And, 6.7V across 4 Ohms works out to about 11 Watts. If you want more power you need more voltage! Note that high-power automotive amplifiers have an internal voltage booster to get higher power from 12V.

A bridge amplifier can deliver 4 times the power with the same voltage, so you can get about 40W from 19V.

i am not familiar with amplifiers, but after searching i think class D amplifiers will be good and i am thinking of this one (http://store3.sure-electronics.com/1-x-40-watt-class-d-audio-amplifier-board-tpa3110 ) , altough it doesnt have SD socket and not sure if it will be compatible with SD shield.

Ferhad88:
the application is hearing test

Ah, now there's a new piece of information!

Nearly all hearing testing is done using headphones, which do not need high power levels.

Usually headphones constructed to block external sounds are used. Most common headphones are made to allow some outside sound in, so you hear if someone nearby is trying to talk with you, or so you can hear something nearby is possibly dangerous. A smaller part of the headphone market is special ones that intentionally block as much outside sound as possible. Those are the type you (probably) want for a hearing test.

Speakers are generally not used for hearing tests. Doing so would cause the actual sound levels the test subject hears to vary depending on the shape of the room, the types of materials, and even whether they rotate their head slightly. For these reasons, sound blocking headphones are almost always used for hearing tests, so you can carefully control the actual sound which arrives at the subjects ears.

it is in an acoustic chamber so it is designed for this reason and there are another tests using headphones, but this one must be using speakers

altough it doesnt have SD socket and not sure if it will be compatible with SD shield.

If it’s an SD audio shield, yes. That amp should work fine, and that’s more than enough power for your application. You will need to add a volume control. :wink:

A SD Card simple memory shield won’t give you audio.

…The Arduino doesn’t have a DAC, so there’s no true analog. There are ways of getting “sound” signals, but if you want good quality an audio shield is the way to go.

but after searching i think class D amplifiers will be good

A class D amplifier is more efficient (it doesn’t generate as much heat as a “normal” Class AB amplifier). That’s usually not as important as the audio specs - Power output, noise, distortion, frequency response.

BTW - You can test the amplifier & speaker independently from the Arduino by plugging in a CD player, DVD player, or you can connect to the headphone output on an iPod or phone etc.

the power supply can deliver up to 26.000 mAh.

mAh is milliamp hours and it’s an indication of battery life, not actual current capability. If it’s a power supply (plugged into the wall) it’s rated in mA or A. 26000 milliamps is 26Amps and that’s plenty! If the specs really say “mAh” they are wrong and you probably bought it on eBay. :smiley: :smiley: