I have a version with larger, taller smd inductors which sounds good even at max volume. I think the saturation is the biggest concern if you often use all of the amps power regularly. If the inductors core material doesn't match the switching frequency the amps usally go into protection. I know cause I tried making my own with wrong inductor core materialIt measured fine with my inductor meter (which used a too low test frequency) but didn't work at all. Tested on a tpa3116 board btw..
If you try to buy larger aftermarket inductors they always cost more than the boards mention here, atleast on eBay.. So paying a 3-5 usd more for better inductors is a bargain! In my experience boards with larger inductors always sound way cleaner at moderate to high volume. Shielded inductors is ofc best but I haven't noticed any sound problems with unshielded toroids either
The Bourns inductors are about 50p or 75 cents in the UK so 4 are about '$3. Should be cheaper in the USA. You also need to check the Electrolytic capacitor as mine had a 25V cap fitted.
Some of these boards have reversed speaker output. Are you shure phase are ok?
20V 3A is about the lowest limit for this amp - that power supply actually puts out 60W maximum power (under ideal conditions). It would be OK for e.g. TPA3116 amp (2x50W), but not for this one, which requires twice the power (logically, since it's 2x100W as compared to 2x50W for the TPA3116). Besides, the speakers you have are not the most sensitive - and also require additional power to drive them properly....
My suggestion is to try a better power supply (20V 5A at least) - that might improve the bass a lot.... provided you connected the speakers correctly (they are incorrectly marked on your board - the same one I have...)
I use the same amp (same board), and am powering it with a 20V 6A "brick" SMPS, and there is definitely no lack of bass. But, I also have very sensitive speakers (98 dB!).
I guess the ideal power supply for this board would be about 24V 6-7A, where the amp wouldn't get too warm (which I guess it does on higher voltage, e.g. 32V), and there would be enough power for the amp - which is not the case with the one you currently have....
In case you go above 24V for the power supply, it would also be wise to change the input power cap (blue one) for a higher rated one - since the original blue is rated at 35V. I've changed this on mine to 2200uF, 63V, just to be on the safe side....
In chosing the power supply for these Class D amps, you need to check the total power rating of the power supply (e.g. 60W and 90W as the usual power ratings for laptop "bricks"). "Rule of thumb" is to multiply the voltage wth current rating (Amps) to get the total output power. In your case, like I said, it's 20 (V) x 3 (A) = 60W. Definitely not enough for this amp... As the lack of bass (usually) shows.
You *might* try adding a larger capacitor (e.g. 2000 uF, at least 35V, but 50V or 63V would be better!) to the power input, to act as a power "reservoir" when the amp tries to draw more power for the bass: that might help a little bit. Just connect it to the power input connector, observing the correct polarity.
But, like I said, the only proper solution is to get a higher rated power supply (at least 90W, as the barest minimum).
Regards,
Denis
You need to do that on only one channel.
Most likely it is the same as on my board, where the right channel has + and - interchanged.
I do not really believe that a new power supply will change anything, if there is 'no bass' even at lower spl with the old psu.
(Of course i nice psu is good to have.)
Have you tried both channels seperately?
24v 15A psu has arrived, connect speaker with polarity + - + - still weak bass, connect with polarity + - - + bass is ok.
this amp Compare with tpa3116 greenboard , vocals more forward and loud, soundstage narrow, lack low bass & detail.
this amp Compare with tpa3116 greenboard , vocals more forward and loud, soundstage narrow, lack low bass & detail.
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I bought one (cheap, black version) of these TDA7498 boards.
However, connected to a laptop "brick" (20V), I hear a very loud turn-on pop when turning on the power...
Anyone have any ideas how one could implement a delay circuit on these?
I used a simple diode + capacitor + resistor delay circuit for my TPA3116, as found in the TPA3116 thread here, but I'm at a loss with this one.... I should probably scrape some varnish off to see the traces - but all components are SMD
I can provide a larger, more detailed photo, if needed...
TIA,
Denis
Any news on this matter?
I'm also getting the loud "turn-on pop" and trying to figure out how to solve it.
There are some options on aliexpress but I'm not sure if will work:
Dual channel UPC1237 Speaker Protection Board Kit Boot Delay DC Protection free shipping-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group
UPC1237 Speaker Protection Board (Compatible with the BTL Protection)-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group
Does anyone have experience with any of those or any other solution?
Thanks!
New stuff:
Recommend !!! HIFI TDA7498E 160W + 160W class D Digital Power Amplifier , Free shipping-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
TDA7498E digital amplifier (160Wx2) red ring inductance-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Which one could be better?
Recommend !!! HIFI TDA7498E 160W + 160W class D Digital Power Amplifier , Free shipping-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
TDA7498E digital amplifier (160Wx2) red ring inductance-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Which one could be better?
Both these units have 35V working power supply caps. The ideal voltage for these amps is 36-39V so the first thing to say is that neither will achieve the stated output without destroying the caps sooner rather than later.
I had one cheap black 7498 to spare and wanted to give it to a friend.
I put it into a small box with connectors, nicer volume pot and everything.
My plan was to tell my friend to use a laptop brick as psu.
I tried a laptop brick i had at home, its values say 19V, 3.42A.
The amp went crazy and was playing music only every 1/4 sec and repeated like that ... on ... off ... all the time.
I measured 13V at the boards power connector with the psu connected.
Then i connected the next psu i had at hand - 12V 5.83A - the board didn't even start up.
To be sure that the amp isn't wrecked i connected 19V from sla batteries and the board worked as usual.
Is my 19V laptop brick wrecked?
Will my friend be able to run the amp with a 19V laptop brick or will all laptop bricks drop voltage that much?
I put it into a small box with connectors, nicer volume pot and everything.
My plan was to tell my friend to use a laptop brick as psu.
I tried a laptop brick i had at home, its values say 19V, 3.42A.
The amp went crazy and was playing music only every 1/4 sec and repeated like that ... on ... off ... all the time.
I measured 13V at the boards power connector with the psu connected.
Then i connected the next psu i had at hand - 12V 5.83A - the board didn't even start up.
To be sure that the amp isn't wrecked i connected 19V from sla batteries and the board worked as usual.
Is my 19V laptop brick wrecked?
Will my friend be able to run the amp with a 19V laptop brick or will all laptop bricks drop voltage that much?
If it's the cheap black board, it requires 18V to run normally.
I've also tried it with 12V - it won't start at all.
So, use proper 19V, and it should work OK.
The first "brick" you tried it with is obviously defective, if it produces only 13V...
Without a load i measure 19V.
It is possible to charge a notebook with it.
It was the first time i recognized the voltage drop to 13V.
Can you confirm that it works with a laptop brick?
BTW, there are some better TDA7498 boards available, like this one:
TDA7498 100W 100W High Power Digital Amplifier Board Amp Board with Radiator | eBay
It's better made, has pin connectors for mute (e.g. ext. mute switch) and provides aux voltage out, and is generally more "solid"... (but, as in most Chinese ebay "blurbs", don't trust anything written in the description)
I've tried that one, and it looks like it's even set up for lower power supply - I've successfully run it on 12V.
Not that it makes much sense, though... (powering it by 12V)
I guess it would work "best" with around 24V - by "best" I mean satisafactory volume levels and dynamics, but still without too much heat generation - and 24V power supplies are still relatively cheap.
Also, given that many of these boards come with 35V rated capacitors, I wouldn't go any higher than 24V (without triple-checking everything first and possibly changing capacitors with higher rated ones).
TDA7498 100W 100W High Power Digital Amplifier Board Amp Board with Radiator | eBay
It's better made, has pin connectors for mute (e.g. ext. mute switch) and provides aux voltage out, and is generally more "solid"... (but, as in most Chinese ebay "blurbs", don't trust anything written in the description
)I've tried that one, and it looks like it's even set up for lower power supply - I've successfully run it on 12V.
Not that it makes much sense, though... (powering it by 12V)
I guess it would work "best" with around 24V - by "best" I mean satisafactory volume levels and dynamics, but still without too much heat generation - and 24V power supplies are still relatively cheap.
Also, given that many of these boards come with 35V rated capacitors, I wouldn't go any higher than 24V (without triple-checking everything first and possibly changing capacitors with higher rated ones).
BTW, there are some better TDA7498 boards available, like this one:
TDA7498 100W 100W High Power Digital Amplifier Board Amp Board with Radiator | eBay
It's better made, has pin connectors for mute (e.g. ext. mute switch) and provides aux voltage out, and is generally more "solid"... (but, as in most Chinese ebay "blurbs", don't trust anything written in the description
I've tried that one, and it looks like it's even set up for lower power supply - I've successfully run it on 12V.
Not that it makes much sense, though... (powering it by 12V)
I guess it would work "best" with around 24V - by "best" I mean satisafactory volume levels and dynamics, but still without too much heat generation - and 24V power supplies are still relatively cheap.
Also, given that many of these boards come with 35V rated capacitors, I wouldn't go any higher than 24V (without triple-checking everything first and possibly changing capacitors with higher rated ones).
I have this board. Bought it based on someone's suggestion from one of these threads (cannot remember which one). This board seems to follow the standard design closedly, including the aux power supply on board (I do not use it). I bought it thru EBay. The packaging was really flimsy and the shield of one of the inductor on the outside was broken.
Even with the broken shield, this amp sounded fine to my ears when I compared it to my 3116 (SMKN board). The base definitely punchier, sound stage slightly bigger, the high is fine too, very similar to my 3116 but slightly noisier. I then complained to the seller about the packaging and sent along pictures. The seller refunded what I paid without even arguing
. So I got it for free! I then decided to change the inductors (since one of them was broken). I replaced them with some Coilcraft SMD inductors that have much better specs. When I took out the original inductors, I measure the inductance and found that the values were all over the place. The reference design specify 22uH (for 8 ohms) and the values I got ranged from from 13 to 22!! I have been listening to this amp for a while now using a 24 V 10 A SMPS and have no complains. The amp can take up to 34 V according to data sheet (I think) so I am not getting the max power output. I am hooking the amp to my 83/84dB planar magnetic speakers thru a TVC and I still have enough volume. Pretty good. I am thinking of swap out the two big power caps (claimed to be Philips, but I doubt it) with some more trusty ones (Panasonic FR or FM). Then I will try running it at 30/32 V to see how it behaves.
Overall, I would recommend this board. These cheap D camps are fun to play with!
Regards,
Denis remember that even with the great efficiency of a Class D amp, say 90%, that still means you need more power to get the rated output so for 50 watts out you need at least around 56 watts. Even that is not true as highest efficiency is at maximum power. I will check the data sheet later to confirm.
My explanation was just a broad generalisation, a "rule of thumb", explaining why the underrated (low wattage) power supply would probably result in poor bass performance.
In general, using a better (higher power /more watts) power supply usually improves things a bit...
Still, I used some of these TDA498 modules even with 12V, and even there (12V/4A) there was no total lack of bass - on very moderate listening levels.
However, like I said, I use very sensitive sepakers (8 Ohm, 98dB)....
On the other hand, you can never be sure with these ebay purchases / boards... Some have different components, even with the same board model, purchased from the same seller: I've bought the same amp boards on separate occasions (from the same seller), and have had wildly different results (sound).
After careful checking, I realised that the "same board" had totally different components: not only e.g. different brand of capacitor, but also different values (different inductor values, mismatched with diferent capacitors and resistors, etc...).
It's the usual risk of buying from ebay - you actually never know what you'll get
If you're good with electronics, you can usually spot the problems yourself - otherwise ask here in the forums, and there will usually be someone to help pointing out potential problems and improvements... That's why I like this forum
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