Hello,
I have a problem with my TDA 7492P Amp (https://www.amazon.de/gp/product/B01JRTZGVM/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1). I have previously got it to work, so I don't know why it isn't working now. I have a Powerbank(Tried 1A and 2.1A port), which is connected to a Boost Converter(https://www.amazon.de/gp/product/B01L1UUMQY/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1), but it is not powering on. I boosted the voltage up to ~15V which worked fine with another converter, but that one kinda broke, because of bad soldering. But if I connect the amp with a 12V wall power supply it works just fine. I'm extremely confused and thought you could help me 🙂
Thank you in advance,
-Lueckii
I have a problem with my TDA 7492P Amp (https://www.amazon.de/gp/product/B01JRTZGVM/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1). I have previously got it to work, so I don't know why it isn't working now. I have a Powerbank(Tried 1A and 2.1A port), which is connected to a Boost Converter(https://www.amazon.de/gp/product/B01L1UUMQY/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1), but it is not powering on. I boosted the voltage up to ~15V which worked fine with another converter, but that one kinda broke, because of bad soldering. But if I connect the amp with a 12V wall power supply it works just fine. I'm extremely confused and thought you could help me 🙂
Thank you in advance,
-Lueckii
Congratulations. I mean, the thread title "TDA 7492P not working when powered" implies it works when not powered on. 😀
SCNR 😉
Power banks usually only deliver 5V, the TDA7492P starts to operate at ~8V. It might work with a bit lower voltage and a power bank delivers usually a tad more than 5V but that drops with current. Maybe it might meet somewhere between but that would be a rare occasion, the under-volt protection triggers at 7V. So I would not expect it to work reliably. I'd suggest you use an amp with a lower voltage requirement or you put in a buck converter (DC-DC/step up converter) between the two.
Edit: At 8V you get only ~6W anyway.
SCNR 😉
Power banks usually only deliver 5V, the TDA7492P starts to operate at ~8V. It might work with a bit lower voltage and a power bank delivers usually a tad more than 5V but that drops with current. Maybe it might meet somewhere between but that would be a rare occasion, the under-volt protection triggers at 7V. So I would not expect it to work reliably. I'd suggest you use an amp with a lower voltage requirement or you put in a buck converter (DC-DC/step up converter) between the two.
Edit: At 8V you get only ~6W anyway.
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He states he's using a boost converter.
Question: Doesn't a power bank already have some form of switched mode voltage altering going on. It's either raising from 3.7V or dropping from 7.4V or similar surely?
@OP: Get a multimeter across the output of the DCDC converter whilst switched. Prove that it is supplying the right voltage. Then measure the current drain on the outputs.
Another option is a failing cell on the powerbank.
Question: Doesn't a power bank already have some form of switched mode voltage altering going on. It's either raising from 3.7V or dropping from 7.4V or similar surely?
@OP: Get a multimeter across the output of the DCDC converter whilst switched. Prove that it is supplying the right voltage. Then measure the current drain on the outputs.
Another option is a failing cell on the powerbank.
That's right. But that voltage is fixed - and the electronics also controls the max battery charge current, maximum charge voltage, low voltage protection against the deep discharge (which would dmg the battery) and the over current protection. To mess with it risks damage to the powered devices, the battery and even can cause fire - LiIon/LiPo batteries don't like being messed with at all.
Sorry for answering so late and thank you for your answers!
The voltage being supplied is 15.03V and it is not drawing any current. It has worked for a short amount of time, then Í unplugged it and plugged it back in, but nothing. It is wired correctly, I checked both ways and tested it with a wall power-supply.
Currently it is wired like this: USB Header -> DCDC Step Up boosting the voltage up to 15.03V -> AMP
The voltage being supplied is 15.03V and it is not drawing any current. It has worked for a short amount of time, then Í unplugged it and plugged it back in, but nothing. It is wired correctly, I checked both ways and tested it with a wall power-supply.
Currently it is wired like this: USB Header -> DCDC Step Up boosting the voltage up to 15.03V -> AMP
I am not that fond with capacitors, what capacity and voltage should it have? And how do I need to wire it exactly?
Your voltage is ~15V so 20V will be fine. The electrolyte capacitor should have 2000-5000µF, that's not very expensive. You wire it parallel to the output of the DC converter, + of the capacitor on + of the power, - on -. If you've got something laying around (defect old amp, radio etc.) it's fine to use that. Just don't use lower voltage (higher is ok ofcourse) and don't mistake the polarity.
Are you sure about the 5000µF? I searched for them and they seem to be quite expensive, about 5€ more than the amp itself
That worked like a charm, thank you so much! 🙂 You just saved the christmas present for my girlfriend c:
Hey guys,
so, I encountered a new problem ._. It is working now using a USB wall adapter, but as soon as I put it in any of my many power banks the power bank just powers off. Yes, every single power bank is working properly and it works with none, but, as I said in my first post, using another boost converter(which is fried because of soldering) it has worked with every power bank I have... I'm just confused right now
I hope you can help my 🙂
so, I encountered a new problem ._. It is working now using a USB wall adapter, but as soon as I put it in any of my many power banks the power bank just powers off. Yes, every single power bank is working properly and it works with none, but, as I said in my first post, using another boost converter(which is fried because of soldering) it has worked with every power bank I have... I'm just confused right now
I hope you can help my 🙂
What power banks are you trying? How many cells and mah does each one have? Do any of them have 12v out or are they all 5v out?
You can boost 5v all you want but the current has to change too. Power = volts X amps and a step up converter doesn't "make" extra power. IMO you probably need to get a 12v power bank and forget about the step up converter. Just because someone on YouTube got it to work doesn't mean it's a good idea.
You can boost 5v all you want but the current has to change too. Power = volts X amps and a step up converter doesn't "make" extra power. IMO you probably need to get a 12v power bank and forget about the step up converter. Just because someone on YouTube got it to work doesn't mean it's a good idea.
I would do that, but it has worked before, on all power banks I own. I know it doesn't make extra power, I'm not new to electronics, but I can't seem to find the problem, because, as I said, on a 5V wall adaptor it runs fine.
I have 4 pbs: 10k mah, 2.1A output; 25k mah, 2.1A output; 3.5k mah, 1A output and 2.2k mah with 1A output. It has worked before on every one of these power banks, but now it won't. My wall adaptor also is 2.1A
I don't really want to buy a 12V power bank as they are too expensive, big, heavy and to much capacity for my purpose
I have 4 pbs: 10k mah, 2.1A output; 25k mah, 2.1A output; 3.5k mah, 1A output and 2.2k mah with 1A output. It has worked before on every one of these power banks, but now it won't. My wall adaptor also is 2.1A
I don't really want to buy a 12V power bank as they are too expensive, big, heavy and to much capacity for my purpose
Watch this video and you'll begin to see the problem with trying to get 15v out of a 5v supply using a typical Chinese step up converter:
https://youtu.be/jYMGCLsytT4
Your arrangement is even worse because inside your power bank is likely another dc-dc converter, either stepping voltage down or stepping voltage up. It's entirely possible that it has a current limiting device that is protecting itself when you try to pull more than 2.1a from the USB port.
You could try adjusting your converter to output from 15 down to 9 volts, close to the minimum voltage the amp needs to power up. At least then you have a fighting chance of getting enough current.
https://youtu.be/jYMGCLsytT4
Your arrangement is even worse because inside your power bank is likely another dc-dc converter, either stepping voltage down or stepping voltage up. It's entirely possible that it has a current limiting device that is protecting itself when you try to pull more than 2.1a from the USB port.
You could try adjusting your converter to output from 15 down to 9 volts, close to the minimum voltage the amp needs to power up. At least then you have a fighting chance of getting enough current.
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I think I start to understand what you mean.. I just measured the current it is taking. On full volume it takes about 1.7A - 2A. I tested this at my PC, which is able to supply ~2A on a modified USB. So you think it's just too much for the powerbanks? Because with the Converter it works just fine on every supply other than a power bank
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The power banks may have a pptc (resettable fuse) to protect against too much current draw. Once you trip a pptc it tends to trip more easily the next time. That may explain why it worked for you once before.
IMO, what you need for that amp is at least a 3x18650 power bank with 12v 3a output. It's the same size and weight as your 10000mah power bank but the 3 cells are in series to give 12.6v. But at 2000-3500mah you may only get a couple of hours of play time depending on quality of cells used and how loud you play it.
Otherwise, switch to a 3w per ch or 6w per ch Bluetooth amp that is designed to run on 5v. Cheap and readily available on eBay.
If you have more speakers you can use the 7492p amp with a laptop brick and make a "home" version for her too.
IMO, what you need for that amp is at least a 3x18650 power bank with 12v 3a output. It's the same size and weight as your 10000mah power bank but the 3 cells are in series to give 12.6v. But at 2000-3500mah you may only get a couple of hours of play time depending on quality of cells used and how loud you play it.
Otherwise, switch to a 3w per ch or 6w per ch Bluetooth amp that is designed to run on 5v. Cheap and readily available on eBay.
If you have more speakers you can use the 7492p amp with a laptop brick and make a "home" version for her too.
The amp doesn't draw a steady current, It changes with the music. If it draws 2A on the modified USB, the peak current is surely higher. Did you measure the current with a digital multimeter? If yes, it isn't fast enough to catch the peaks. Powerbanks are built to deliver a (relatively) steady current, with the dc converter it obviously fluctuates too much. The capacitor evens it out to a degee but not if the current is too high permanently. You can try to move it to before the converter but it wont work either way if you constantly drawing too much power. I thought you would stay within it's (reasonable) limits, it seems you didn't limit the input signal at all though. "Mit Gewalt bekommt man alles kaputt" 😉
I second the recommendation for a (much) smaller amp built for 5V. If you don't limit anything, go for two of the 3W ones, they are well within the limits (1,2A) while two 6W can peak at 2,4A - which is probably too much already if you don't have any control.
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