Audio amplifier compatability...

[That one guy]

So, i got an Audio amplifier board that was meant for 10w stereo speakers. My question is this, can i connect 30w speakers to it instead and still get the desired audio output? Thanks.

The amp board im using-
http://www.ebay.com/itm/Audio-Amp-B...dfad990&pid=100005&rk=5&rkt=6&sd=262715740518

 

[Harald Kapp]

The power rating of an amplifier is the power it can deliver.
The power rating of a speaker is the power it can dissipate without being destroyed.

As long as the power rating of the speaker is equal to or higher than the power rating of the amplifier the combination will work well.

 

[That one guy]

Great, thank you so much. What a relief !

 

[Audioguru]

The Chinese seller lies about the output power of the amplifier.
The datasheet for the PAM8610 IC shows 5W into 8 ohms with low distortion, 8W with considerable distortion and 10W with severe clipping distortion when its supply is 12V.

 

[That one guy]

The Chinese seller lies about the output power of the amplifier.
The datasheet for the PAM8610 IC shows 5W into 8 ohms with low distortion, 8W with considerable distortion and 10W with severe clipping distortion when its supply is 12V.

Ok so say i use a 9V battery and microphone connecting it to a set of 10w speakers and 30w speakers seperately, What would happen?

 

[ramussons]

Well, to start with, that battery won't last long........

 

[That one guy]

The battery is not much of an issue, the problem is its not working right when i connect it to a mic. When i touch the mic it gets some sort of static.

 

[donkey]

the battery MIGHT be the issue. if not enough current to run the speakers and amplifier then get a distorted sound.
also could be a faulty connection in the mic.
lets rule out a few things, plug mic into a KNOWN WORKING amp and try it
Try speakers on a KNOWN WORKING amp
try a 12volt power supply on the existing amp
then all that's left is the INSIDE the amp like the mic connection

 

[Audioguru]

It looks like you have not looked at the datasheet for the PAM8610 IC used in the Chinese amplifier. It shows that its minimum supply is 7V (that a 9V battery will quickly drop below) and its output to an 8 ohm speaker is only 2W at low distortion. A little 9V alkaline battery is designed to power something that uses 0.4W for 10 hours when its voltage has dropped to only 6V.

Since you have "static" sounds when you touch the mic then the mic is probably not connected properly. Maybe the mic can hear the speaker and the system produces acoustical feedback howling? Then record the mic and play it back when the mic is turned off.

 

[Chemelec]

As to Power, It is actually better to have an amplifier that delivers a Power Equal To or Greater Power than the Speakers rating.
An Amplifier that is rated TOO LOW in power will cause Considerable Distortion and SQUARE Waves at a Louder Volume.
A 100 watt Amplifier driving a 10 watt Speaker is Better that a 10 watt Amplifier driving a 100 watt Speaker.

Square Waves are NOT what you want to drive a Speaker.
Square waves can cause the Voice Coil to pull away from the Speaker Cone.

 

[That one guy]

Well i met with this electronics expert that i knew and he looked at the thing,
we tested it, providing audio input from a radio and it worked great. He said that the audio input jack is not meant for a microphone to be directly plugged in. Btw for the mic, im using a simple circuit mic which does not have its own independent power. could that be the problem?

Also im getting a pair of 10w speakers, ill see if that works.

 

[Audioguru]

We talk in detail here. What is "a simple circuit mic"? All mics have a name and all have almost the same low level. The most common mic today is called "electret condenser" and it does not work without power. An older mic is called "dynamic" and it is like a little speaker with a magnet and a coil of wire and when sounds move its coil over the magnet then it generates a signal.

The Chinese amplifier ad does not say what is its important "sensitivity". You did not say that the output level is low, instead you said it produced static when you touched the mic.

A 30W 8 ohm speaker, a 10W 8 ohm speaker and a 2W 8 ohm speaker will all produce about the same amount of sound from the 2W Chinese amplifier. The datasheet for the PAM8610 amplifier shows that its output power is doubled to 4W when its speaker is 4 ohms (or two 8 ohm speakers in parallel) and its supply is 7V.

Today I noticed that the PAM8610 IC is a stereo amplifier so it has two channels, its output sound will be doubled to be a little louder and a 9V battery will last half as long.

 

[That one guy]

well this is what it looks like:






[mod note -- images resized]

 

[davenn]

. Btw for the mic, im using a simple circuit mic which does not have its own independent power. could that be the problem?

you have shown an electret condenser mic .... these require a specific voltage driver to work

here's one of dozens of examples that are on the net



Dave

 

[Audioguru]

An electret mic draws a current of 0.5mA so with a 9V supply and a 27k resistor, the voltage feeding the mic is 9V - (27k x 0.5mA)= nothing. For a 9V supply I use 10k then the mic gets 4V and it works well. If the supply is 12V then the resistor should be (12V - 4V)/0.5mA= 16k.

If the Chinese manufacturer copied the circuit in the datasheet of Diodes Inc. then the amplifier needs an input of about 265mV but an electret mic produces about only 10mV unless you scream at it. So you probably need a preamp to boost the 10mV mic signal to 265mV.