TDA7492 Amp

[SEWS]

Which chip? Which board?

the blue one with the heat sink from Ebay. i did it, there is no pins or jumpers, the 2 Gain Pins are ending to smd resistors, 333 each one. What should i do? soldering out and shorting it?

 

[jwicaksana]

If you like warmer sound, Sanwu TDA8932 monoblock is excellent. Very musical and deep deep bass - amazing for its size.

look for tda7498 and tda8932.
you should take into account that yj red tpa3116 is one of the worst sounding modules with that chip.

1. TPA3118 PBTL mono block Sanwu blue board circa $8ea (needs gain lowering mod) good up to 40w for low distortion.
2. TDA8932 Sanwu mono, circa $4ea (use as is works fine but lower power)
3. TDA7498 big black heatsink, vol pot, circa $12 (if you need more than 40w, this is good)

Due to space constraints, having monoblocks with separate power supplies are not an option for this particular application. Temporarily, this amp will have to work with a 6 Ohm speakers and 12V 3.3A supply. Which one of these would work best in this scenario?

TPA3123 25WX2 Digital Audio Power Amplifier Board Better YDA138 TA2024 TDA7297 | eBay

YDA138 E Yamaha 10W 10W Dual Channel Digital Audio Amplifier Board DC 12V | eBay

DC 12V 24V TDA7492P 25W X2 Dual 2 0 Channel Digital Audio Power Amplifier Board | eBay

TDA7498 Class D 2X100W Dual Channel Audio Stereo Digital Amplifier Board 14 32V | eBay

TDA7498 100W 100W Class D Amplifier Board Computer Amplifier New | eBay

Thanks for taking the time to help.

 

[Buehgemeiste]

for a 12v supply imo the sanwu TPA3118 would be best.

 

[jwicaksana]

Of course, the 3118, why didn't I think of that. Any thoughts on regular vs D2 version?

TPA3118D2 Digital Audio Power Amplifier Assembled Board Dual Track 25W 25W Mono | eBay

TPA3118 Digital Mini Audio Power Amplifier Board Dual Track 25W 25W PBTL 50W | eBay

 

[jwicaksana]

Sorry I take the discussion away from the 7492 amp, I'll do some reading on the 3118 thread, looks like a lively one there. Have a good weekend chaps.

 

[tiefbassuebertr]

Have you looked at the data sheet to see what pin needs "adjusting" and how?

No. Good advice - thank you.

I explained how to do this in post 216 right above. Cut the traces that provide Vdd (3.5v) to pins 30 and 31 and you will get the lowest gain of 21.6dB. You need a magnifier, a sharp exacto razor with a pointy tip and steady hands.

This I will do next time, maybe this provides the wanted effect of additional noise reduction.

Sure, the polystyrene caps can work as snubber caps as long as voltage rating is sufficient.

Look at Figure 28: break the traces for pins 30 & 31 (open) to get lowest gain setting of 21.6dB, leave 31 connected to Vdd (3.3v) and break pin 30 to get 27.6dB, leave pin 30 connected to Vdd and break pin 31 t0 get 31.1dB gain. Both connected is 33.6dB.

http://www2.st.com/content/ccc/reso...df/jcr:content/translations/en.CD00205863.pdf

Thank you; yes, on page 24/32 of this datasheet I find this so as the fact, that the input resistance through use of an inverted mode is in all cases at least 60K. This means, that the lowest possible input noise is dependend from this resistor.

Nevertheless I want to have the genuine schematic of this amp, because I want to compare all details with the application examples from the TDA7492 datasheet.

 

[tiefbassuebertr]

I explained how to do this in post 216 right above. Cut the traces that provide Vdd (3.5v) to pins 30 and 31 and you will get the lowest gain of 21.6dB. You need a magnifier, a sharp exacto razor with a pointy tip and steady hands.

last week I try to do this - but after dismantling the heatsink from PCB unfortunately I note, that both PCB wires - going to the pins 30+31 - are not connected in standart configuration (genuine condition from S.M.S.L.). Means this, that the residual idle noise by shorted input occurs only by the integrated 60K input resistor (go to page 24/32 from the TDA7492 datasheet) ?
If yes, are there successor ICs from ST in the meantime available, where this integrated resistor have lower values with otherwise unchanged properties ?

 

[jerwer1]

Hello
Can someone explain me what the function is of the 1n F caps)to earth ) behind the 470 nF input caps .(see schematic TDA 7492) I removed the 4x 470 nF input caps and replaced them with input transformers but left the 1nf smd caps in place .
regards
Jeremy

 

[DUG]

Hello
Can someone explain me what the function is of the 1n F caps)to earth ) behind the 470 nF input caps .

...
Jeremy

Usually to keep (or significantly reduce) RF from getting into the input circuitry.

 

[aveei]

An externally hosted image should be here but it was not working when we last tested it.

Hi,
Can someone tell me if the snubber circuit is just soldered to the board because at these spots on my board there is nothing?

 

[ivicanikolic034]

Hello, i have this amp:
TDA7492 bluetoot 4.0 2*50W

i want to connect this speaker to it:

80w 8ohm


i want to do it in mono, so i can avoid not hearing the other channel in music. How can i do it? Can i mod the amp so it plays only mono? Or join channels to get 1x100w. I think i saw similar TDA7492 amps with mono, but can i mod mine to be similar?


Other solution is to split speaker in channels. Look at the picture. A (4ohm) for right, B(8ohm)+ C(4ohm) for left (with some kind of cap on B). But i dont know how will it work, i am total beginner.

Forcing mono on phone (audio sorce) is not the option.

 

[ravels]

Unfortunately, forcing the source to be mono is the best option.

Otherwise, you really need a summing circuit with an opamp.

Or you can use a quick hack of a passive "summing circuit", which is technically not great, but may be acceptable depending on your application. This circuit goes between your source (phone) and the input of the amp.

 

[ivicanikolic034]

I dont want to use 80w speaker on one 50w channel. I want to use as much power as possible, to be efficient. Thats why i want to distribute power between both channels.
Is there any other mono 100w bluetooth amp that you can recommend, but not more expensive than mine, on aliexpress (or ebay from china)?

I will use speaker for outdoor hangouts, drinking with friends, so nothing special. I dont need perfection.
I dont really understand what to do on my amp, can you explain me exactly for my situation. I can buy parts and solder, i know how to do that. But nothing more, i am even worse than a beginner in audio equipment.

 

[Buehgemeiste]

Making the the play mono is the biggest task here.
My guess is that the speaker in the pic has a built in crossover.
Maybe only a cap in series to the tweeter.
But some kind of crossover will be there if it is in its original state.
I would buy another amp.
Even a seperated bluetooth module and a mono amp board will be easier to handle.

What is the nominal impedance of the speaker?

 

[Buehgemeiste]

There will be not too much difference in sound pressure between 50w and 80w.
But this amp will never give you 50w on one channel.

What kind of battery do you have?

 

[ivicanikolic034]

There is a cap, you can see blue thing painted in the picture :-D i cant see specification, i need to melt glue and see if needed.
On the speaker back (speaker box) it says 80w 8ohm.

 

[ivicanikolic034]

There will be not too much difference in sound pressure between 50w and 80w.
But this amp will never give you 50w on one channel.

What kind of battery do you have?

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

 

[ravels]

With a 12V supply and a 8-ohm speaker, the most power you can get from that amp is about 10W.

 

[Buehgemeiste]

Be aware that you will never get high power out of 12V, unless you use an step up converter, which sucks you battery empty much faster.
At 25w your battery will be empty after 1 hour.
\footnote{There is much more to explain, but that is not what you should take care of right now.}
The key for a loud outdoor system is a high efficiency speaker.
The speaker in the pic is maybe somewhere between 80db and 85db, which is very low.
For now you should try what you have and make your own experiences.
Keep in mind that this is amp is made for 8 Ohm on each channel.
You can try all of the speakers in parallel (the tweeter with a series cap) on a TPA3118 mono board.

 

[Buehgemeiste]

You can try that amp with the speakers configured as you described (woofer+tweeter on one channel, one woofer on the other channel):
https://www.aliexpress.com/item/TPA...lgo_pvid=c25b9159-8d48-4c1a-a637-7ed13eea0a2b