I dont know how to wire this simple amp

[Richard Crowley]

Note that a true Class-D amplifier typically has a FLOATING output where NEITHER side is allowed to be grounded.
They must be connected to a floating load. Typically a speaker voice-coil.

If you were really using a Class-D amplifier, then one possibility could be that you have grounded one side of the output. Perhaps to test gear.
But since you have identified your board as using a TDA2030A chip, then it is not a "Class-D" amplifier as originally stated.

[Hextejas]

Sheesh, such a simple problem to generate this much discussion. I bought these amps as throw away items, no tears if I burn them up.
What I need it for is for testing a tuner to see if a 1khz signal is getting through. I wanted a very small footprint, easy connections to a very small footprint speaker. I have limited space on my work bench so this beast looks ideal.
It sounds like I will need to give it more juice. I had not bothered reading the spec sheet, I just assumed that the 9v battery would be ample.
Thanks.

[Richard Crowley]

Sheesh, such a simple problem to generate this much discussion. I bought these amps as throw away items, no tears if I burn them up.

You asked a good question. But remember that your question, the clarifications, and the responses are not JUST about YOU  They are archived here for the benefit of hundreds or thousands of future readers with a similar question or issue.

[6PTsocket]

Sheesh, such a simple problem to generate this much discussion. I bought these amps as throw away items, no tears if I burn them up.
What I need it for is for testing a tuner to see if a 1khz signal is getting through. I wanted a very small footprint, easy connections to a very small footprint speaker. I have limited space on my work bench so this beast looks ideal.
It sounds like I will need to give it more juice. I had not bothered reading the spec sheet, I just assumed that the 9v battery would be ample.
Thanks.

Two 9 volt batteries should do the trick. If you run with a single power supply you will need a capacitor to couple a speaker to the amp or you will have half the DC voltage on the speaker. Not a good thing. It is amazing how all the ebay sellers have the same bad info. on their sites. I guess they all get them from the same  wholesale source in China.

Sent from my SM-G900V using Tapatalk

[Hextejas]

Sheesh, such a simple problem to generate this much discussion. I bought these amps as throw away items, no tears if I burn them up.
What I need it for is for testing a tuner to see if a 1khz signal is getting through. I wanted a very small footprint, easy connections to a very small footprint speaker. I have limited space on my work bench so this beast looks ideal.
It sounds like I will need to give it more juice. I had not bothered reading the spec sheet, I just assumed that the 9v battery would be ample.
Thanks.

Two 9 volt batteries should do the trick. If you run with a single power supply you will need a capacitor to couple a speaker to the amp or you will have half the DC voltage on the speaker. Not a good thing. It is amazing how all the ebay sellers have the same bad info. on their sites. I guess they all get them from the same  wholesale source in China.

Sent from my SM-G900V using Tapatalk

6pt, thank you, and could you point me to some reading material that could explain why it would be " a bad  thing " for me to wire my desktop 18v supply to this amp. Cause that is exactly what I was planning on doing.

[Zero999]

Sheesh, such a simple problem to generate this much discussion. I bought these amps as throw away items, no tears if I burn them up.
What I need it for is for testing a tuner to see if a 1khz signal is getting through. I wanted a very small footprint, easy connections to a very small footprint speaker. I have limited space on my work bench so this beast looks ideal.
It sounds like I will need to give it more juice. I had not bothered reading the spec sheet, I just assumed that the 9v battery would be ample.
Thanks.

Two 9 volt batteries should do the trick. If you run with a single power supply you will need a capacitor to couple a speaker to the amp or you will have half the DC voltage on the speaker. Not a good thing. It is amazing how all the ebay sellers have the same bad info. on their sites. I guess they all get them from the same  wholesale source in China.

Sent from my SM-G900V using Tapatalk

6pt, thank you, and could you point me to some reading material that could explain why it would be " a bad  thing " for me to wire my desktop 18v supply to this amp. Cause that is exactly what I was planning on doing.

It would work perfectly from a bench supply. There should be no need for any additional capacitor, as going by the photograph of the board, it's clearly designed for single supply operation, with that large capacitor next to the speaker terminals.

[6PTsocket]

I posted some bad info. Sorry. Pull up the data sheet for the TDA2030A from any of the companies that made it. There will be drawings of it running  from a single supply like your 18 volts and with a split supply like   two 9 volt batteries in series. With the 18 volt supply the minus terminal of the supply is ground. With two batteries in series, the tie point between them is ground. The ebay photo showed two grounds. One of them is actually the negative DC connection to the amplifier and the other is signal ground. In a single supply like your 18 volts they are tied together and you must use the 2200 mfd capacitor in one speaker lead or there will be 9 volts DC on the speaker along with the signal. In the split supply with 2 batteries, the signal ground is connected to the tie point between the batteries and no capacitor is needed. In that case we are using the tie point as ground and it is half way between +9 and -9  so it is zero and there is zero volts DC on the speaker. The input and the speaker use the tie point as the  - or ground connection. I know it can be confusing. It is because you have two wiring options that there are two grounds on the ebay picture One goes to pin 3 on the chip. That is the one that is always tied to the most negative supply voltage. The other one is only tied to it when running a single supply with no center tap.

Sheesh, such a simple problem to generate this much discussion. I bought these amps as throw away items, no tears if I burn them up.
What I need it for is for testing a tuner to see if a 1khz signal is getting through. I wanted a very small footprint, easy connections to a very small footprint speaker. I have limited space on my work bench so this beast looks ideal.
It sounds like I will need to give it more juice. I had not bothered reading the spec sheet, I just assumed that the 9v battery would be ample.
Thanks.

Two 9 volt batteries should do the trick. If you run with a single power supply you will need a capacitor to couple a speaker to the amp or you will have half the DC voltage on the speaker. Not a good thing. It is amazing how all the ebay sellers have the same bad info. on their sites. I guess they all get them from the same  wholesale source in China.

Sent from my SM-G900V using Tapatalk

6pt, thank you, and could you point me to some reading material that could explain why it would be " a bad  thing " for me to wire my desktop 18v supply to this amp. Cause that is exactly what I was planning on doing.

Sent from my SM-G900V using Tapatalk

[Zero999]

I doubt two 9V batteries would do a good job at powering a TDA2030 amplifier. It certainly wouldn't work for long, at any decent power level. The internal resistance of a typical 9V battery is about 2.1 Ohms, when fresh, which would be 4.2 Ohms for two in series, so a load current of just 1A would cause the voltage to drop by 4.2V. What's worse is the internal resistance increases, as the battery discharges and at lower temperatures. The quiescent current taken by the TDA2030 is also quite high and is the sort of load a 9V battery is designed to power on its own. Using a large decoupling capacitor across the batteries will help to some degree, but this still isn't ideal.
http://www.zeusbatteryproducts.com/wp-content/uploads/Zeus_9V.pdf

A much larger battery is required, such as three 6V lantern batteries or 12 AA cells in series, to power the TDA2030 properly.

[tooki]

Sheesh, such a simple problem to generate this much discussion. I bought these amps as throw away items, no tears if I burn them up.
What I need it for is for testing a tuner to see if a 1khz signal is getting through. I wanted a very small footprint, easy connections to a very small footprint speaker. I have limited space on my work bench so this beast looks ideal.
It sounds like I will need to give it more juice. I had not bothered reading the spec sheet, I just assumed that the 9v battery would be ample.
Thanks.

If time isn’t of the essence, consider buying a cheap PAM8403 audio amp board from eBay. They’re class-D, run happily off 2.5-5V (so 3 AA batteries, or 3.3V or 5V from an existing circuit, are ideal; >5.5V will fry it), tiny, and cheap as dirt, even in the “fancy” versions with a built in volume pot.

FWIW, you can’t be blamed for assuming it’d run off 9V, since the eBay listing clearly (yet demonstrably incorrectly) says 6-12V.

[mariush]

If you want something super simple and cheap, you could always go for a PAM8301 ... mono amp, up to ~ 1.5w @ 8 ohm it's basically the chip and 3 ceramic capacitors... gives you around 1w at 8 ohm with ~ 90%efficiency:

$0.54 at Digikey: https://www.digikey.com/product-detail/en/diodes-incorporated/PAM8301AAF/PAM8301AAFDICT-ND/8283873

Datasheet: https://www.diodes.com/assets/Datasheets/PAM8301.pdf

Super easy to put on a prototyping board, just bend up the middle contacts and you solder the edge contacts on 0.1" proto board and solder a wire to the middle contacts or something like that... you can use it with power from usb or from 2-3 AA batteries.

For a stereo amp, even easier to solder to a prototyping board as the contacts are 0.1" apart, you have PAM8403: https://www.digikey.com/product-detail/en/diodes-incorporated/PAM8403DR-H/PAM8403DR-HDICT-ND/8545994
Still cheap, at around $0.75 on Digikey ... though if you buy only a couple dollars worth from Digikey, they'll probably charge you something like 5-10$ for shipping.

[Hextejas]

Those PAM devices look kewl and they're cheap enough. So I am going to get some. 

[6PTsocket]

My suggestion of two 9 volt batteries was mostly to illustrate a split power supply. It really  is too small to be usefull. I was trying to point out why he would have to use a cap with the speaker  if he could not get to the "center tap" on the supply. If he goes with a split supply he has to figure out which of those two "grounds" in his picture is ground and which is V- to the chip, as they would no longer be tied together.

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[tooki]

The thing is prewired as a PCB. It’s very unlikely that it can be used with a split power supply. I reckon the chances that the two ground terminals aren’t permanently connected are somewhere between zero, zilch, and nil.

[oPossum]

I have that exact board. The two ground pins are both connected to the ground plane. It would have to be modded to run with split supplies.

[oPossum]

I did a brief test of this amp board.

At 12V the idle current is 35 mA. Enough volume to hear it over the fan of the HP 6632A that is powering it.

At 9V the idle current is 30 mA. It has usable clean output.

At 6V there is noticeable distortion at moderate volume.

At 4V it is essentially useless.

[6PTsocket]

That doesn't sound like a big job. Pin 3 is V- on the IC. Just cut the land and bring out a wire from pin 3. It is probably best that he just use a speaker cap and  single ended supply. The data sheet says 2200 mfd but if he does not need low end response it can be smaller.

I have that exact board. The two ground pins are both connected to the ground plane. It would have to be modded to run with split supplies.

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[Zero999]

But why would you want to modify it to work on a split rail?

Also note that, yes it's true that most ICs will work outside their specifications, but not all will work or be reliable: it's uncharted territory. Another thing is it might work from a 9V bench supply, which has a very low impedance, but a 9V battery is another matter. It might work from a 9V battery for a short length of time, have a distorted output or not at all.

[Richard Crowley]

Note that the standard PP3 size battery has the LEAST capacity of any commonly available battery/cell.
While they have the nominal 9V rating, they have a very low current/power rating because they are made from six AAAA cells (or equivalent).



The TDA2030 was never designed to operate from such a low-capacity power source.
Certainly there ARE power amp chips that ARE designed to operate from 9V batteries.



Ref: https://en.wikipedia.org/wiki/Nine-volt_battery

[tooki]

That doesn't sound like a big job. Pin 3 is V- on the IC. Just cut the land and bring out a wire from pin 3. It is probably best that he just use a speaker cap and  single ended supply. The data sheet says 2200 mfd but if he does not need low end response it can be smaller.

I have that exact board. The two ground pins are both connected to the ground plane. It would have to be modded to run with split supplies.

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Why are you so hell-bent on him using the split supply? There’s no compelling reason to do so, especially not since it requires modifying the PCB. And why do you assume the PCB doesn’t already have the speaker cap? It’s a finished amp board, not a bare IC breakout board!