I dont know how to wire this simple amp - Page 1
Forum section: electronics / beginners

author: Hextejas
author_rank: Frequent Contributor
timestamp: August 31, 2018, 07:17:22 pm
content: I am trying to hook my signal generator to a cheap. class D mono, amplifier.The amp has 4 inputs.1. VCC2. In3 Gnd4 Gndand I hooked them like this:1) VCC = +9v2) In = 1khz test tone + lead3) Gnd = -9v4) Gnd = 1khz - leadIs this correct and how come I cant hear anything ?

author: BergRD
author_rank: Contributor
timestamp: August 31, 2018, 07:21:21 pm
content: Silly question here, so please ignore, but have you hooked up the output to speaker(s)?Just covering the bases here and KISS theory.

author: Hextejas
author_rank: Frequent Contributor
timestamp: August 31, 2018, 07:34:34 pm
content: Yes I did and not a silly question. The thing is that I had another el cheapo stereo amp and it was working until it stopped. Dont know why, I prolly fried something on it.I swapped it out for this mono beauty. but no sound.

author: P_Doped
author_rank: Contributor
timestamp: August 31, 2018, 07:47:36 pm
content: 1) Is the - terminal of your signal source floating or is it connected to earth ground?Just wondering since you have both a -9V supply and the - terminal connected to the same potential on the board.2) Do you know if the board can take a total of 18V between the VCC/Gnd pins?3) If you measure the voltage between the VCC & Gnd pins, do you see 18V?4) Do your 9V supplies have the ability to display their output current (could be 9V batteries, for all I know)? If so, what type of current are they showing?5) What are the electrical characteristics of the speaker hooked up to the board?

author: Hextejas
author_rank: Frequent Contributor
timestamp: August 31, 2018, 08:04:04 pm
content: Quote from: P_Doped on August 31, 2018, 07:47:36 pm1) Is the - terminal of your signal source floating or is it connected to earth ground?Its connected to one of the "Gnd" marked connections on the board.Just wondering since you have both a -9V supply and the - terminal connected to the same potential on the board.2) Do you know if the board can take a total of 18V between the VCC/Gnd pins?Dont know3) If you measure the voltage between the VCC & Gnd pins, do you see 18V?I will check4) Do your 9V supplies have the ability to display their output current (could be 9V batteries, for all I know)? If so, what type of current are they showing?It is a 9v battery5) What are the electrical characteristics of the speaker hooked up to the board?I think that they are an 8ohm desktop style speaker, but I will look more closely tomorrow.

author: glarsson
author_rank: Frequent Contributor
timestamp: August 31, 2018, 08:05:41 pm
content: I read the description as one 9V battery with plus to Vcc and minus to GND.

author: Zero999
author_rank: Super Contributor
timestamp: August 31, 2018, 08:15:41 pm
content: Quote from: glarsson on August 31, 2018, 08:05:41 pmYes, going from the original poster's description, It's not a dual power supply, but a single 9V battery. By convention, saying +/-9V power implies a bipolar PSU, with a total voltage of 18V and a centre tap in the middle, which is the 0V. This can confuse beginners who''ll take a 9V battery and call one side +9V and the other -9V, which is incorrect.Quote from: Hextejas on August 31, 2018, 07:17:22 pmSo you have a single 9V battery, giving a total supply voltage of 9V. In this case the correct terminology is 9V and 0V or ground, as +/-9V implies a bipolar 9V supply, i.e. two 9V batteries in series, with the ground or 0V terminal being where the two batteries join.Are you sure the battery is good? Have you measured the battery voltage, with the amplifier connected to it?I doubt a small 9V battery will be able to power this amplifier for long, if at all. A power supply with a higher current capability i.e. lower internal resistance is required to power this amplifier properly.

author: P_Doped
author_rank: Contributor
timestamp: August 31, 2018, 08:50:49 pm
content: Okay, not 2 9V supplies but 1. I understand now.I agree with Hero999, a single 9V battery has a large internal resistance of 1 - 2 ohms. It could be that as soon as the device on the board starts to consume reasonable currents, maybe at startup or soon after the audio is driving the speaker, that 9V battery doesn't look so 9V anymore and the chip stops and restarts (many chips have under voltage detection which gates their operation if the supply is below a defined minimum).If you have an oscilloscope, watching the across VCC/Gnd would tell you if the battery is holding up. I'm guessing you don't have such a device at hand.You could also try putting together your own "9V" with 6 AA batteries in series and seeing if that works.

author: Audioguru
author_rank: Super Contributor
timestamp: September 01, 2018, 12:49:08 am
content: Please post a link to the amplifier and the part number of its IC.

author: gedong
author_rank: Contributor
timestamp: September 01, 2018, 01:04:45 am
content: from the OP image it's unlikely to be Class D amp. more like chip ampquick googling its seems like single supply version of TDA2030/50

author: Brumby
author_rank: Unknown
timestamp: September 01, 2018, 01:36:06 am
content: Have you checked the speaker?Simple field test: Use a 1.5V battery and a couple of wires connected to the speaker terminals. Hold one wire to one end of the battery and briefly tap the other wire to the other end of the battery (polarity not important). You should hear a pop and/or crackle.The actual sound doesn't matter - just whenever the circuit is completed/broken you get some sort of noise at a clearly audible level, the speaker is good. This is a simple test that proves continuity and cone movement.Don't have the battery connected for anything more than a fraction of a second. A constant DC voltage will prove nothing as the cone will be held in one position and sound is only created with cone movement. Also, if you have a low impedance speaker with a low power rating, connecting a battery for too long may heat up the voice coil. In those cases, just brush the second wire over the second battery terminal.A multimeter continuity test will show if there is a circuit, but it may not offer enough current for an audible response. If the speaker cone is jammed, then it may not produce any sound, even though the voice coil is intact.

author: rdl
author_rank: Super Contributor
timestamp: September 01, 2018, 04:34:36 am
content: Pretty much every seller of electronic doodads from China offers those amplifier modules.https://www.ebay.com/itm/TDA2030A-Audio-Amplifier-Module-Power-Amplifier-Board-AMP-6-12V-1-18W/192163691131

author: Hextejas
author_rank: Frequent Contributor
timestamp: September 01, 2018, 11:27:33 am
content: Quote from: rdl on September 01, 2018, 04:34:36 amThat's the one I have. Thank you rdl. Now back to my questions. The 9v is a battery and I have a 1kHz tone at 5v coming from a signal generator. The battery has a pos and a neg terminal. And so does the generator. So what wire goes to which of the 4 connections ?Maybe there is not enough juice in the 9v to be able to push this speaker. It worked ok with the prior amp,, although it was a different device. A cheap Chinese stereo amp.

author: StillTrying
author_rank: Super Contributor
timestamp: September 01, 2018, 12:04:33 pm
content: The minimum voltage for the TDA2030A is 12V or +/-6V, and 50mA quiescent current, so you'll have to try it with a bit more voltage and current.The ebay link looks like someone has thought +/- 6V is the same as 6V - 12V.Are the 2 GNDs pins on the board actually connected together.

author: Zero999
author_rank: Super Contributor
timestamp: September 01, 2018, 12:50:41 pm
content: As mentioned above, the TDA2030 is not a class D amplifier, but a class AB amplifier. It is also completely unsuitable for operation at 9V. If you need it to run off a 9V battery, your best option is to return it, get a refund and buy an amplifier which really will work off 9V.https://www.ebay.com/itm/DC-3V-9V-TDA2822M-Mini-Mono-Audio-Single-Power-Volume-2W-Amplifier-Board-Module/252840104297?epid=722098777&hash=item3ade71d169:g:75UAAOSw4CFY33PKIf you want to keep your this amplifier, then you need a much higher power supply voltage. Although the TDA2030 will work off 12V, it still isn't optimal and at 12V will probably only give an output power of 2W, into a 4Ω speaker or 1W into an 8Ω speaker. A 24V power supply is ideal. Two 12V 7Ah sealed lead acid batteries and a 5A fuse would be perfect for powering the TRDA2030.

author: Audioguru
author_rank: Super Contributor
timestamp: September 01, 2018, 01:22:44 pm
content: Why do people buy cheap Chinese junk from ebay who knows no Engrish and knows no elekronics.

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 01, 2018, 01:50:06 pm
content: Quote from: P_Doped on August 31, 2018, 07:47:36 pmFrom the OP's description and the picture, it is a single ended 9 volt supply There is no mention of a + and - supply, unless I missed something or he left it out. Maybe that is the problemSent from my SM-G900V using Tapatalk

author: Zero999
author_rank: Super Contributor
timestamp: September 01, 2018, 01:54:19 pm
content: Quote from: Audioguru on September 01, 2018, 01:22:44 pmYou appear to have forgotten that this is the beginners section.If someone doesn't have much electronics knowledge then how are they supposed to judge the knowledge of the seller and know what to buy?Yes, there are plenty of crappy products on ebay, but there are some very good ones too.

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 02, 2018, 02:29:06 pm
content: I just looked at the TDA 2030A data sheet and there is nothing to suggest that it was ever intended to run with a single ended supply voltage. The specs are +or- 6 to + or - 22 volts. What was misread as two grounds were the actual ground and the minus power supply connection. A pair of 9 volt batteries would work for as long as they lasted, which might not be much.Sent from my SM-G900V using Tapatalk

author: mariush
author_rank: Super Contributor
timestamp: September 02, 2018, 02:59:46 pm
content: TDA2030 (and the others in the series, like the much better TDA2050 for example) can be run with split power supply or with a single power supply - the circuit is slightly different but not by much.See the attached datasheet, at page 8, you will see example circuits for either split power supply (where you would use at least +6v and -6v supplies to power the board), and an example circuit which can run with a simpler supply of just +12v or more.The chip requires a minimum of 12v to work (or -6v supply AND 6v supply for a total of 12v difference) and can work with up to 36v ( or -18v AND +18v in split power supply mode) - see page 3 in the datasheet where these numbers are shown.The efficiency of this kind of amplifier (class AB and average performance wise) is at around 60% , so it needs a lot of voltage to output a reasonable amount of sound, and it also heats (hence the heatsinks on it).You can look on page 5 of the datasheet and you'll see there figure 4 and figure 5 .. output power vs supply voltage ... you should only care about figure 4, where the drawing is for distortion of 0.5% ... the other figure is for distortion up to 10% which is not great for music (but if you want to make an amplifier for announcements in a train station for example you wouldn't care about music and this would be acceptable)So back to figure 4, you can see there that 4 ohm speakers are easier for the amplifier and it will output more sound power with 4 ohm speakers. So you can see there they don't even calculate how the chip would work with 12v ( or -6v and 6v) , they start right from +/- 8v (or 16v dc) ... at that point you can see that the chip can output just a bit over 2w on a 8 ohm speaker, and just around 4 watts with a 4 ohm speaker.So basically, you need a much higher power supply to use this amplifier, my suggestion would be using one of those laptop adapters that output anything between 16.5v and 19v, they should be super easy to find.Alternatively, you should look for a 15v..24v AC transformer and use a bridge rectifier and a capacitor to convert this 15v..24v AC to around 20..32v DC. As long as the voltage will be below the maximum this chip supports (and below the input capacitor's voltage rating on the board you have .So also look at the voltage rating on the capacitors on your board and if for example it says 25v on the capacitor, then you shouldn't use more than around 24v at the input, unless you replace the capacitor with one rated for higher voltage (35v or 50v rating)For testing that the board actually works, the easiest for you would probably be to connect two 9v batteries in series. Though note that 9v batteries aren't really designed to give a lot of energy to devices, so the amplifier chip may try to take too much out of the batteries and then the voltage on the batteries will drop quickly.I'm attaching the tda2030 datasheet below:

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 02, 2018, 04:16:24 pm
content: OOPS !! I stand corrected. I never went through all the data sheets. It will run from a single or split power supply. Is one preferable? It is not a whole lot more work to build a split supply.Quote from: 6PTsocket on September 02, 2018, 02:29:06 pmSent from my SM-G900V using Tapatalk

author: mariush
author_rank: Super Contributor
timestamp: September 02, 2018, 04:40:08 pm
content: Quote from: 6PTsocket on September 02, 2018, 04:16:24 pmSplit power supplies save you one big capacitor (in series with by the speaker with single power supply).Also makes easier to do bridge amps (see datasheet for example), to use 2 x tda2030 with one speaker to get more power.anyway, for experiments, it may make more sense to buy some tda2050 chips and use example circuit from datasheet or google and you'll find complete schematics on dyi sites.from memory tda2050 works from 10v and up (or -5v and 5v) so it would be very easy to use with a 12v atx power supply or a laptop adapter

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 02, 2018, 07:13:56 pm
content: Quote from: mariush on September 02, 2018, 04:40:08 pmThere is a little speaker protection with a cap against power supply imbalance failure damage but I never had any problems with my old Sony 110W per channel direct coupled amp. I would go with a split supply.Sent from my SM-G900V using Tapatalk

author: Audioguru
author_rank: Super Contributor
timestamp: September 02, 2018, 07:17:03 pm
content: Quote from: mariush on September 02, 2018, 04:40:08 pmThe TDA2050 is obsolete and is not made anymore. Digikey has none.With a 12V supply its output power was only 2W if the speaker was 4 ohms or 8 ohms.

author: Zero999
author_rank: Super Contributor
timestamp: September 02, 2018, 07:32:59 pm
content: Quote from: Audioguru on September 02, 2018, 07:17:03 pmTDA2050 amplifier modules are still widely available on ebad, probably using new old stock parts, more than fakes. The LM1875 is a suitable replacement, according to Google.Yes, an IC designed for 12V operation should be used, perhaps the LM4940 can be bridged to give around 4W into an 8Ω load, with reasonably low distortion?http://www.ti.com/lit/ds/symlink/lm4940.pdf

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 02, 2018, 07:48:55 pm
content: 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.

author: Hextejas
author_rank: Frequent Contributor
timestamp: September 02, 2018, 09:22:37 pm
content: 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.

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 02, 2018, 10:38:52 pm
content: Quote from: Hextejas on September 02, 2018, 09:22:37 pmYou 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.

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 02, 2018, 11:50:28 pm
content: Quote from: Hextejas on September 02, 2018, 09:22:37 pmTwo 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

author: Hextejas
author_rank: Frequent Contributor
timestamp: September 03, 2018, 02:36:04 am
content: Quote from: 6PTsocket on September 02, 2018, 11:50:28 pm6pt, 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.

author: Zero999
author_rank: Super Contributor
timestamp: September 03, 2018, 07:43:01 am
content: Quote from: Hextejas on September 03, 2018, 02:36:04 amIt 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.

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 03, 2018, 08:27:32 am
content: 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.Quote from: Hextejas on September 03, 2018, 02:36:04 amSent from my SM-G900V using Tapatalk

author: Zero999
author_rank: Super Contributor
timestamp: September 03, 2018, 09:41:29 am
content: 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.pdfA much larger battery is required, such as three 6V lantern batteries or 12 AA cells in series, to power the TDA2030 properly.

author: tooki
author_rank: Super Contributor
timestamp: September 03, 2018, 11:00:58 am
content: Quote from: Hextejas on September 02, 2018, 09:22:37 pmIf 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.

author: mariush
author_rank: Super Contributor
timestamp: September 03, 2018, 11:16:30 am
content: 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/8283873Datasheet:https://www.diodes.com/assets/Datasheets/PAM8301.pdfSuper 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/8545994Still 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.

author: Hextejas
author_rank: Frequent Contributor
timestamp: September 03, 2018, 12:30:05 pm
content: Those PAM devices look kewl and they're cheap enough. So I am going to get some.

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 03, 2018, 03:39:56 pm
content: 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.Sent from my SM-G900V using Tapatalk

author: tooki
author_rank: Super Contributor
timestamp: September 04, 2018, 12:57:31 am
content: 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.

author: oPossum
author_rank: Super Contributor
timestamp: September 04, 2018, 05:12:45 am
content: 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.

author: oPossum
author_rank: Super Contributor
timestamp: September 04, 2018, 05:45:55 am
content: 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.

author: 6PTsocket
author_rank: Regular Contributor
timestamp: September 04, 2018, 02:19:30 pm
content: 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.Quote from: oPossum on September 04, 2018, 05:12:45 amSent from my SM-G900V using Tapatalk

author: Zero999
author_rank: Super Contributor
timestamp: September 04, 2018, 07:26:12 pm
content: 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.

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 04, 2018, 08:27:58 pm
content: 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

author: tooki
author_rank: Super Contributor
timestamp: September 05, 2018, 10:47:10 am
content: Quote from: 6PTsocket on September 04, 2018, 02:19:30 pmWhy 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!