Voltlog #78 - Building a 2x25W Bluetooth 4.1 Stereo Amplifier TDA7492P

[@kalleklp7291]

I have the version without jack input. I soldered a wire to the Bluetooth antenna on the board. It greatly extended the range of the B.t.. A small (10 cm ) piece of wire will do. Alternatively one can get self-adhesive copper tape cheap on eBay. It will also work.

[@Hugatry]

Great job, that's a good looking and functional amplifier! Many people tell to not leave the antenna of wifi/bluetooth device inside the case. But like you told in this video, that just reduces the signal strength while some people make it seem like the signal would be totally unusable. The lower signal strength may be sufficient. For my setup, 2-3m range would be plenty. It's all about what each of us needs, everyone doesn't need maximum performance.

[@voltlog]

Exactly, I am happy with this setup but it can be adjusted if one would need the extra range.

[@medvidekkrupicka1404]

I think that the metallic enclosure is a weak point of this design. A plastic box would perform much better.

[@voltlog]

a plastic box will allow for increased bluetooth range, but if that's not something you need, the aluminium enclosure looks better :-)

[@Benri05]

I use this amplfier to power 2x 4ohms speakers and 2x 8ohm speakers in a diy boombox and it works well. I installed an intel heatsink underneath the pcb for better heat dissipation.

[@patrykskrzyniarz1356]

Can I power a 19W, 9A power supply for 4OHM 15W speakers? Good project 😉

[@clembas74]

Very nice project ! By the way, do you think it is possible to wire a volume potentiometer to your board, working for both aux line input and Bluetooth input ? Thanks

[@GlennPierce]

I recently completed my house audio sync project for a cheap alternative to Sonos and evaluated one on these. The one I bought didn't have switches on the aux socket. Also beware if people want to use the aux socket. Mine had more noise than signal.

[@voltlog]

the module in the video doesn't have any additional noise for the line signal because it's routed to the same point as the bluetooth signal, the input of the pre-amp.

[@AlexBarrow]

Glenn Pierce which amp did you use for your home audio?

[@GlennPierce]

I used a array of these www.banggood.com/PAM8610-Digital-Amplifier-Board-2x15W-Two-Channel-Stereo-Class-D-p-1029691.html?rmmds=myorder Ok for me and background music. Probably wouldn't keep and audiophile happy. My code is at github.com/glennpierce/PartyZone

[@Uncle-Mal]

Hi. Great video. I have a noob question for you. You stated in the video you could remove the buttons and wire new buttons. Would show how to do that? I would send you a new amp if need be to see how that is done. I have zero soldering skills but I am learning and would love to be able to hook up new momentary switches to that amp to place it into a speaker enclosure. Thanks!

[@voltlog]

You don't even need to remove the existing buttons, you can just solder wires and add a second set of buttons in parallel, it will work just fine. You need two wires for each button, just find the pads where the signal connects, and solder thin wires to them, I think the two pads on the left of each switch are the ones you need, but double check that.

[@Uncle-Mal]

Thanks for the information. I'll let you know how if I am able to get it to work. Thank you for responding also.

[@MrBrymstond]

You just solder the wire to the end of the internal Bluetooth antenna and run a connection for the external antenna right?

[@voltlog]

Don't do that, you will just affect the existing antenna with no extra gain. Antenna theory is a more advanced topic.

[@MrBrymstond]

Okay thanks. I seen a lot of videos with people doing this and it didn't look right but I figured to ask being so many did this.

[@MechaTronic161]

MrBrymstond < It really helps if you use a magnet wire and wind the wire properly. Not only strengthen the BT signal but also eliminate the backround noise.

[@radiantfairy4079]

Thank you for the great video. I have a newbie question. I have 2 speakers. Each is 3ohm @ 30W. What would be a good power brick spec that I should use? Hoping for your response sir. Thank you.

[@radiantfairy4079]

If you have a link that I can use to purchase, that would be great. 😁

[@randomthings2843]

can u play a music with 3.5 Aux in without modified the bluetooth firmware?

[@blackbrayn]

I was looking into those cheap d class amplifiers , you can get pretty powerful ones for a decent price.

[@voltlog]

they're nice, I like the power vs quality vs price ratio that you get from these.

[@stephanc7192]

Please show the addition of an external antenna. Kind regards

[@a.travelgrapher]

I am using the same amplifier board, but confused how do you switch between the bluetooth and 3.5mm line input? Please guide

[@stilios4745]

Great project, I am in possession of the same amplifier and considering of building the similar enclosure but of plastic. How did you applied this heat sink on it - glue it?

[@voltlog]

The heatsink already had some thin double sided tape when I purchased it. A plastic enclosure would improve the signal strength.

[@SatoshiBall]

I am considering buying the TDA4792P Bluetooth board. I have a 4 ohm speaker that has an RMS of 30Watts and Peak Power Handling of 60Watts so should I buy the 2x50W version or the 2x25W version as it says 'best at 8 ohms'. Does that mean it will be 2x100W at 4 ohms? Please help. It would be appreciated. : )

[@perfdavid]

I'm a noob at this. I am using these boards to make old antique radios into Bluetooth speakers. I want to solder an led so when it is powered up it will have a light on the dial. Where did you solder the led onto the board? It was hard to see in the video. Thanks

[@voltlog]

led was soldered on the existing led pads.

[@seppedev]

How did you connect the led to the board? Did you use a resistor or wasn't that necessary?

[@voltlog]

I used the connections for the existing power LED present on the PCB, Which is already connected through a resistor.

[@SuperBoobaloo]

Nice build! I ordered one of those amps from eBay, but it was DOA. Seller magically disappeared before I ever got the problem resolved...

[@voltlog]

paypal/ebay should refund you in that case..

[@REALdruide99]

I am about to build my own portable bluetooth speaker and might need some help. I have got 1 speaker cabinet (with speakers) [Poineer S-p370): - Music Power [DIN] 50W - Puissance Musicale [DIN] 50W - Impedance 6 ohm. I was going to buy the TDA7492P 50W+50W (red one) and hook my speaker up to one of the 2 channels. I am trying to power this system with 4X Vander 18650 Akku 6000mAh Rechargeable Li-ion Battery (14,8 Volts in total). As I am not familiar with speakers and technical stuff like you, I was interested in your and others opinion if this is a good idea... :D?

[@TheKetsa]

What range are you getting ? I have a bluetooth receiver that cannot manage more than 2-3 meters and that's out of a case. Also, I need to be able to use an audio-in jack, were you unable to use it in the end ? not sure from the video. Thanks.

[@TheDirty360]

+1, I have this exact module and the bluetooth range is terrible. I have two of them and tried sacrificing one for testing with a remote antenna, cutting the PCB antenna with minimal benefit.

[@voltlog]

The range I'm getting is 3m with direct line of sight between phone and amp module, with the module inside the aluminium case. I established the connection within 1m and then moved away towards the far end of the room with no interruptions. I am not able to use the audio-in jack, they don't seem to be using the switch on the jack, it looks like they are mixing the bluetooth signal and the line in before the pre-amp chip however I am unable to play anything through the line input. While playing something through bluetooth the line in signal does get through so what I suspect is that they use a mosfet (Q1 maybe) to switch the power to the pre-amp on only while there is something played through bluetooth. I doesn't make allot of sense to design it this way though..

[@TheKetsa]

VoltLog Thanks a lot for the answer. I need another solution then.

[@voltlog]

With a hack I think you could use this one as well. But there are other modules out there.. you could try a different one.

[@TheKetsa]

I was wondering if there could be a trick to cut the antenna trace and solder a standard antenna in place ? but I dont know how, had a look online and didnt find a solution.

[@correia707]

Hello. I recently bought one of this amps, but when i plug a laptop charger to it (its a 19v 4A) already connected to AC, the amp gives a lot of sparks o.O Do you know whats the problem? Also i tried to measure the amperage of the amp in use but it simply got sparks in the multimeter terminals... is something wrong there?

[@jonathanbryandechavez7460]

Hey i want to know where to connect the positive and negative in the 2.1 interface?? I am using a battery and i dont know to connect it in the board

[@felixcat4346]

When will we see the DYI dummy load project?

[@voltlog]

considering the holidays I'm estimating it will be published maybe mid January.

[@iceberg789]

nicely assembled.

[@voltlog]

It wasn't really planned, I had that enclosure for over a year without any purpose in mind, same for the speaker output connector. That's the advantage of having a nice selection of parts in the lab.

[@sanb3586]

Hey there is more then 1 models i ordered 100*2 one can you tell me how can i check its either 25+25 or 50+50?

[@DheerajKumar-dk747]

1. Is it powered by dual ICs, ie. NE5532 & tda7492? 2. Can we add WiFi module with this amp. board?

[@jotasgasco]

Hello, due to my poor understanding of english i can´t really get to know where do you say you can get the bluetooth line out to send it to another amplifier, as i´m building a portable speaker and i need a separate amplifier with low pass filter, i need to know where i can get that line out if you or someone would be kind enough to tell me the exact points please. Thanks.

[@MechaTronic161]

jotasgasco < It should be the output of the Op Amp chip.

[@claytonneill1825]

Where did you solder the wires for the 3.5mm jack? I have one of these and would like to do this mod

[@voltlog]

Here is a link to the wiring diagram but please note that is a line out signal from the bluetooth module. It's not a line in as I initially thought. www.voltlog.com/wp-content/uploads/2016/12/wiring.jpg

[@oOIvN]

VoltLog. Good video! I have a question for you, in your diagram you connected two terminals to each cable but in the video only connected a terminal for cable...why!?

[@Maverickoulos]

Salut, Fain continutul canalului, te urmaresc cu placere. Am 2 astfel de placi (cea rosie cu 2x25 si cea galbena cu 2x50). Ambele au fost legate la difuzoare de calitate de 12ohm si alimentate de la un pachet custom de celule LiIon 6S2P (~25V max). Dupa o anumita perioada de utilizare ambele au inceput sa faca figuri, respectiv absolut aleator se restarteaza (gen power-down, power-up). Vreo idee de ce?

[@DogRox]

sweet system!! excellent job!! :-)

[@voltlog]

thanks!

[@isprithul]

Hi, which soldering iron/station are you using? Thanks

[@voltlog]

kzbin.info/www/bejne/pGnTpmmaqpWZqrs

[@LEO-xo9cz]

Why no heatsinks?

[@user-tj1el9uo1m]

Hey sire Is it possible to show us in a video how to replace an pcb atena to a external atena. Im sure other people will also such a video. Btw great video i will make wan my self :)

[@Ivo--]

Tip: you can use a vacuum cleaner to get dents out of speaker cones.

[@voltlog]

+spankmeister thank you for the hint

[@dtwistrewind7361]

VoltLog don't do it that's the worst idea I've ever heard it stands more chance of damaging it, the way to do it is put some tape on the center of the dent and press into area then do not pull out towards you,instead pull the ends of tape with both hands to the left and right at the same time just stretching the tape brings out the dent without yanking at the cap with unnecessary pressure.

[@LieroXor]

Hi! Your project look very nice. I want to make my own one but, everywhere it's called 2x50W. This 2x50W is a MAX power? So the TRUE power is 2x25 yeah? And i dont know how to power it... Is any difference if I power it with 12 V and 24 V? with 12 V it will be not full 25W? In specs is 8 to 24 V, but when i want to power it from 12,6 V Li-Po battery (with BMS and balance) this amplifier willl be work on 25W? One more, this 25W is RMS? Soory for be poor but i need help ! :D

[@voltlog]

you can read the datasheet of the TDA7492P for full info. It's 2 x 25W.

[@LieroXor]

@VoltLog OKay, i read both. The difference is in "P" letter at the end of name. TDA7492P is 2x25 but TDA7492 is 2x50. A lot of people on AliExpress call TDA7492P as 2x50, what is lie... I only have problem with power supply because i want to use LiPo 18650 but i need 6S to get ~20V and full power. PCM/BMS boards for 6S is expensive and i dont know how i would to charge it :/

[@voltlog]

with a BMS board you could charge the batteries with a current limited buck regulator.. not ideal but it will work. The problem is you are trying to use a chip that was not designed for battery powered applications in a battery powered scenario :-)

[@czarzenana5125]

+LieroXor Why bother so much for the output power? Doubling the output-power will only increase the sound level with +3dB which is noticeable, but no more than that. You'd be better off searching for speakers with high sensitivity.

[@pitbylllson]

2-3 meters? Thats nothing.. Can someone buy a antenna or something to help with the range? Great video by the way!

[@TheDefpom]

I noticed the centre caps of the speakers are pushed in, a little trick to fix that is to use a vacuum cleaner to suck them back out :-)

[@voltlog]

I purchased them for $10 used so I can't complain but thanks for the trick I will try to do that :-)

[@isprithul]

What is the dimension of the heatsink? Thanks

[@voltlog]

there is a link in the description of the video

[@isprithul]

Sorry didn't notice it. Thanks

[@nickd.5171]

If you put it at max volume does it make continuous pauses? Because my mine does!!

[@voltlog]

I never actually used it at max volume, so I don't know..

[@wi_zeus6798]

A small correction: In the beginning you talk about the amplifier. On the bottom of the screen is a text that says: ... "2x50W"... The title of your video is 25W. So there must be a small mistake. :) But apart from that, Very Nice Video!

[@voltlog]

yes, there is a mistake. I had my head filled with all the bullshit advertising from ebay and got that title wrong. The amplifier is 2 x 25W.

[@wi_zeus6798]

VoltLog Ok, nobody's perfect

[@spoderman15]

+Manuauto Actually, I never make msitakes

[@wi_zeus6798]

Spoder Man 1/10 too much bad jokes. Seriously, you are not perfect either.

[@Wuppie62]

25W rms or peak?

[@AlexBarrow]

When I plug in the aux it doesn't switch from Bluetooth, I'm I missing something?

[@voltlog]

I discovered that is not an AUX port but rather a line out from the bluetooth, so you can use the module as a simple bluetooth receiver and pass the signal through another amplifier.

[@CristianHreniuc]

de ce neapatat 3 amperi?

[@bhaibhai-qp6fh]

Where led is to be solder

[@fredlllll]

i recently bought this thing here www.banggood.com/TPA3116-100W-Bluetooth-4_0-Audio-Receiver-HiFi-Stereo-Amp-Amplifier-Board-p-1059332.html?rmmds=myorder it works, but you can hear a loud buzzing from the bluetooth data. so i had to saw the module off, cause i suck at desoldering. very annoying, but with the lag of bluetooth it would not have been a usable solution anyway. are the any ICs which just take mosfets that can be chosen by the engineer?

[@voltlog]

the one I have seems to be using a good pre-amp, the noise level is okay for my ears. If you would like to search for different amps I would start by looking at TexasInstruments Audio section, they have quite a nice selection. Also STmicro.

[@KJW648]

why cover the button up, they included volume buttons, which increase the default volume of the BT, gain switches just add distortion.

[@AdrianCosic]

The sound should be good , I connected a 2 x 15W amp to my 2.1 system and sound was very good , lot of bass.

[@voltlog]

yep, the sound is good.

[@AdrianCosic]

I got mine amp for 1,2$ from alice :D

[@muzguz7276]

You put it in a Faraday cage.

[@TheSeanm101]

Why would you want to rebuild that if one of the parts cost $10 from China when the whole entire board cost $12 on Amazon you could get the same day you order it am I missing something here?

[@voltlog]

There are several reasons one would want to build such a module himself and I could list some for example: 1. the pleasure of making something yourself 2. higher quality, better build quality, better parts 3. customization: maybe you need something done a bit different

[@akarshagarwal4516]

nice

[@voltlog]

thanks!

[@livinglife5978]

not worth the trouble,after long periods of time using it it getting hot,even after 20 min usage with large speaker's,you need to mount a fan to cool down the chip.and can use a plastic enclosure to increase the signal on Bluetooth

[@HowDareYouu]

buy the YELLOW version - is newer and muchhh better

[@дедНиколай-в5к]

Genius херня китайская !

[@TheSeanm101]

Why would you want to rebuild that if one of the parts cost $10 from China when the whole entire board cost $12 on Amazon you could get the same day you order it am I missing something here?