TDA7492 Amp

[ivicanikolic034]

Which cap should i use for woofer+tweeter? Woofer is 4ohm, tweeter is 8ohm.
The amp that you linked is also stereo.

 

[nastorrent]

I am thinking about sealed lead battery, 12v 2.3Ah. It can fit inside speaker box.

I have tested this same amp with 4 18650 cells and it works at good volume more than 18 hours before recharge. The battery gives 16.8V fully charged.

 

[ivicanikolic034]

I have tested this same amp with 4 18650 cells and it works at good volume more than 18 hours before recharge. The battery gives 16.8V fully charged.

I was an idiot and i bought 12v 7.2Ah SLA batery... After 3 hours of playing, it is still on max voltage, so i guess it didnt discharge a single bit... So im now stuck with huge,heavy battery that will last for days :-D

Sent from my Nexus 5X using Tapatalk

 

[nastorrent]

If you have some old dead notebook batteries, you can take out the cells and with a cheap BMS board sure you can make a small battery for a few bucks.

 

[ivicanikolic034]

If you have some old dead notebook batteries, you can take out the cells and with a cheap BMS board sure you can make a small battery for a few bucks.

I have,but they are very old and bad.
Doesnt matter, i payed only $13 for new sla battery with 1 year warranty. Only downside is - it weigths 2kg :-D

Sent from my Nexus 5X using Tapatalk

 

[nastorrent]

There are good how-tos on recovering dead battery cells!
Most of the times, it's some bad component on the battery's BMS, or one definitely dead cell, but I have taken up to 6 "full-shape" cells from one dead notebook battery!

 

[jsdspif]

I have been using a tda7492 amp from indeed for a year or so. The other day when I turned it on it had no output. The led is lit and the power supply is fine, just didn't have any output. I've read thru most of this thread and didn't see any mention of some common problem that occurs with the amp. So, I was wondering if anyone has any idea what might have happened to cause it not to work? I'm probably able to do various checks of voltages and what not, but working on the surface mount stuff is out of the question for me, too shaky. I just thought someone may have had a similar experience and could point out things to take a look at. Thanks

 

[ariP]

Hi everybody
Just joined
See this TDA7492 thread last post is back 2017. Hope to get an answer on this.
I have a kkmoon tda7492 BT
want to power it with a 6x18650 pack jointed with a 6s BMS. one doubt. If I have the bms can I recharge batteries' pack just powering the bms with any adapter or is it still necessary to use a li-ion charger?
In both cases which power/Ah/watt should the power source supply given I have 6x3.7v batteries each 3A
Thanks a lot
Ciao

 

[grahamgraham]

Hi all,

Is the conclusion that the TDA7492 amp board in the OP not a good bet and that the TDA7498 was better?

After reading this whole thread (including parts I don't understand) is there a conclusive suggested mod for the OP board?

The TDA7498 is a little large and volt hungry for me, I would like to use 20v(ish) PSUs.

The price for the TDA7492 is now around £4.50 a board so is very attractive. I am looking to buy two amps to bi-amp an SB12PFC25-4 and a TC9FD (4 & 8 ohms respectively).

 

[Dunk02]

Hi, just enclosed this board in a case and would like to try the suggested mods.

First Q, are to two mods still recommend?

Secondly, it appears from the images that the original power filter cap was REPLACED with the three recommended caps, however, the text says ADDED TO - (So I proceeded to add a pair of Panasonic OSCON 330uF 25V SEPF caps and a Panasonic 560uF 35V FM cap to the single stock 2200uF 25V cap that was there). Which is it?

Also, the original cap is 1000uF in the schematic and on my board. What is the 2200uF mentioned?

Thanks

Having been a big TPA3316D2 user and fan for over 2 years now, I am just starting to use the very low-cost TDA7492 amp boards available from China. I recently bought a pair from Aliexpress for about $8 ea shipping included. They arrived in a few weeks and I have since set them up, and even started modifying them in a way similar to the TPA3116D2 with regards to power rail caps and snubbers. I think this amp deserves its own thread to keep the 3116 thread on topic...


Datasheet here: TDA7492 - 50 W + 50 W dual BTL class-D audio amplifier - STMicroelectronics



For the purposes of comparison of sound quality between the TPA3116D2 and the TDA7492's (both amps have same mods), I am using rather nice speakers that I just finished building - the ScanSpeak 10F/8424 & Dayton RS225-8 Ref Monitor shown here:



This is the current monitor's measured response and acoustic XO:



Group delay for this monitor (sealed Limkwitz transform bass) is +/- 2.5ms above 33Hz:



Here are the amps now connected to my miniDSP powering my ScanSpeak 10F/8424 & Dayton RS225-8 FAST reference speakers (10F/8424 & RS225-8 FAST / WAW Ref Monitor - diyAudio):



Having shown you the performance of the reference monitors, I can say that using these speakers, compared to the 3116, these amps sounded OK stock, but seemed a bit harsh and edgy on the top end, and lacked some forcefulness in the bass department. So I proceeded to add a pair of Panasonic OSCON 330uF 25V SEPF caps and a Panasonic 560uF 35V FM cap to the single stock 2200uF 25V cap that was there. I also added 330pF and 10R snubbers at the inputs of the inductors. With the mods in place, this amp sounds very very good! I think it has better high frequency resolution that the 3116, and the extra snubber smoothed out the harshness. The OSCON upgrade always helps - a lot better bass authority and the sound stage and imaging improved.



Here is how I added 330pF and 10R snubbers to the input side of the inductors, basically same location where the "bootstrap" snubbers would go on the 3116. Note that the TDA7492 does not have external bootstap caps.



I pulled the massive heatsink off of the board to reveal a Feixiang pcb - here is a high res layout photo. It looks like the Feixiang board pretty much follows the suggested circuit but as you can see from the photo, they added some stuff like a protection diode on Vcc, and a pair of small SMT by-pass caps after the electrolytics very close to the pins for the best noise suppression - a nice touch. Input and output filter caps are EPCOS films. The input caps have been upgraded from factory suggested 470nF to 1uF EPCOS film caps. The output filters seem to be using a compromise arrangement of 22uH and 220nF and 100nF film caps. Usually this would be with 33uH inductors. :



The amps run warmer than the 3116, but one of my amps runs hotter than the other and one of the inductors (far right) runs hot to the touch which is why I am looking at it closely to see what the problem is. It looks like the ferrite shield casing is chipped or cracked.

Here is the datasheet suggested schematic:



Here are the datasheet pinouts:



You can get these for circa $7 shipping included:
Page Not Found - Aliexpress.com

 

[xrk971]

I forgot all about this thread for like 5 years now. Just stumblrd on it again.

s the conclusion that the TDA7492 amp board in the OP not a good bet and that the TDA7498 was better?

I do think the 7498 sounds better and it runs fine on 19v SMPS laptop supply.

 

[rbryantaz]

This thread seems a bit dead but it seems like the right place.

I have been playing with tpa3116 boards and also bought a pair of 7492s and 7498s. I am about to give them a shot.

I opened a freshly arrived package with a cheap 7492 board and found that it did not match the sellers description and came with a 25V 1000uF cap when it was supposed to be a 35v. I can change it but I thought it would be good to point out so that others don't set theirs to the 26v without looking and blow it up.

The 7492 has very small output inductors compared to the others. Those probably have a current rating of less than 1.5 amps. I see specs on some CDR74 (7mmx4mm) inductors at 1.25 to 1.84amps I will have to see if I can heat them up on the bench.

Here is a comparison of the 7492, 7498, and xh-m543(single chip stereo tpa3116).

Note the CHR127 (12x7) inductors on the 7498 and 3116 boards. Those should handle over 3 amps (3 amps for the 33uH, 3.6amps for the 22uH and over 5 for a 10uH due to larger wire on the lower inductor parts) I am looking at upgrading these to CHR129's in the future which can handle about 40% more current than the 12x7s.

I also ordered a silver heatsink version of the 7492 board that has different caps (polypropylene instead of polyester). I haven't ordered the single cap 7498 board shown above yet. I may still do that, the quality of this board with the many capacitors isn't that great. It is a pretty messy solder job, etc.

-Rich

 

[rbryantaz]

I suggest against buying the above 7492 board. I replaced the capacitor and put it on the bench. I really only got about 19-20w of clean power before clipping into 8 ohms on each of the two boards that I have with the black heatsink and orange (polyester?) caps .. They also had very loud screaming inductors as the power increased. IIRC it was evident at over 10-15W.

I also purchased another version of essentially the same board with a silver heatsink and square (polypropylene?) caps. I got it on aliexpress and it looks like it is the same one that partsexpress has.

I was able to get 25W at 24V from the second board with less inductor screaming. So the components do seem to make a big difference. Note that this board did have its capacitor tops dented during shipping and I have not replaced them yet. I will have to see if I can get the full 30w that JohnAudioTech got un his youtube review once I do that.

I also noted that these generated quite a bit more heat than the tpa3116 boards. The distortion is also nastier on the tda7492 and tda7498 where it breaks before clipping and doesn't clip cleanly like the tpa3116 chip does.

 

[pcgab]

I suggest against buying the above 7492 board. I replaced the capacitor and put it on the bench. I really only got about 19-20w of clean power before clipping into 8 ohms on each of the two boards that I have with the black heatsink and orange (polyester?) caps .. They also had very loud screaming inductors as the power increased. IIRC it was evident at over 10-15W.

I also purchased another version of essentially the same board with a silver heatsink and square (polypropylene?) caps. I got it on aliexpress and it looks like it is the same one that partsexpress has.

I was able to get 25W at 24V from the second board with less inductor screaming. So the components do seem to make a big difference. Note that this board did have its capacitor tops dented during shipping and I have not replaced them yet. I will have to see if I can get the full 30w that JohnAudioTech got un his youtube review once I do that.

I also noted that these generated quite a bit more heat than the tpa3116 boards. The distortion is also nastier on the tda7492 and tda7498 where it breaks before clipping and doesn't clip cleanly like the tpa3116 chip does.

I wonder if replacement inductors, with somewhat higher rating, could be easily obtained?

 

[rbryantaz]

I wonder if replacement inductors, with somewhat higher rating, could be easily obtained?

They should be easy to get.

I replaced the 12mm x 7mm inductors on my tpa3116 boards to 12mmx9mm. I will have to check but I think these are 10/4s and could go with a larger 10mm inductor. The 12mm inductors might fit but it would be tight and probably require desodering some other components. It is very easy to melt the edge of a capacitor when trying to get these off. I had some brushes on my board but it didn't do any real harm.

I may take a look, the board with the black heatsink is pretty terrible compared to the other one. I Think it is the caps rather than the inductors though.

-Rich