What the heck? It's less than lunch!

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#581
faramirex said:
Hello, I would like to ask for some help.

I bought a TDA7297 amplifier (this) and I tried 3 different power source (DC) and I got no bass.

I tried with
5V 1A (USB), no noise, but no bass
12V 12A (XBOX360 PSU), big noise, no bass
8.5V 1.5A (Camera charger), big noise, no bass.
Click to expand...

Do you know what the impedance curve of your speakers looks like? Perhaps the impedance is too low at bass frequencies for this little amp to push sufficient current. Just a guess.
 
#583
Given "The Big Noise" I suggest that the input potentiometer has failed or is of unusable quality.
Try replacement with ordinary resistors.
3.3k from input to centerpoint.
22k (or 25k) from centerpoint to ground.

The source will see 25k3 load, but the amp will see 22k load.

About 13%~16% of the input voltage will get lost that way; however, a greater amount of noise will get lost.

The amp offers 6W~8W good audio along with 10W~22W headroom capacity of sketchy quality. So, all you need be concerned with is that first 8W of decent. If we can get enough voltage to push that, then the rest is just there for extra fun.

Other steps: The input capacitance can be raised up to 470n so as to allow more bass to pass.
 
#584
faramirex said:
Hello, I would like to ask for some help.

I bought a TDA7297 amplifier (this) and I tried 3 different power source (DC) and I got no bass.

I tried with
5V 1A (USB), no noise, but no bass
12V 12A (XBOX360 PSU), big noise, no bass
8.5V 1.5A (Camera charger), big noise, no bass.

Could you help me Guys why I have a crap sound quality? Everywhere I read this amplifier have good sound quality , but not for me.

Thanks!
Click to expand...

Those are all junk. And like I said on the other forum the input capacitors are too small for a lot of bass. You should use 1uf film input capacitors, at at least 12v. You need somewhat efficient speakers too.
 
#585
I successfully solved the crap sound quality problem... I got 2 defect audio jack cable, adn this caused the problems with the quality, it was hard to believe the chance for having 2 defect cable , and I re soldered all thing on the PCB and now got less noise, finally I put a Step-Up converter to the input, so I made 13V from 5V or 8.5V, I know I loss some power, but less noise with the 8.5V adapter, and higher volume from USB power banks. But now it is okay.

I tried to solder the ground to the body of the potentiometer, but then the potentiometer worked weird.

I will try to get some capacitors, just the local radio shack got nothing... Could you guys help me pick the right ones from this site please?

Thanks for the help! 🙂
 
#586
Thanks to a generous forum member who has helped me get things right,

I have managed to put something together which i am very happy with. The board is fed with a 13.8v input and the upgraded capacitors maintain the original board values.

Power supply capacitor swap:
Nichicon UHW1E222MHD (Digikey part :493-6873-ND)

Input capacitor swap :
Nichicon UKW1H2R2MDD1TD (Digikey part :493-10794-1-ND)

This version of the amplifier bypasses all the diodes with the use of the DC connector. Both diodes have since been removed (no jumper required).
The one on the left has the capacitor and terminal block swap.

 
#590
Just got mine Hot Rodded a bit .... Left the diode and the small ceramic cap in ... As usual, photos to follow....

Changing the big input cap made a HUGE difference, less so with the output ( I think ) film caps, but we can natter about function once I post photos.

Dave
 
#594
radiosmuck said:
Anyone tried a TDA7379 board with bluetooth, it's lunch money with a couple of beers?
2015 New Arrival Tube Amplifier 4.0 Bluetooth Amplifier Board Tda7379 40w+40w Stereo for Audio Power with Krc 86b Module Car-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Click to expand...

I think you're better off with one of these things:
12V Car Bluetooth MP3 Wireless Audio Module USB TF Radio WMA Decoder Board | eBay
Plus it has the remote and different inputs 🙂 Just hook it up to your tda7297 board for 5$ and you're set.
 
#595
I have had mine for a couple of weeks, I got rid of the diode, it seems to have better clarity. This weekend I will changing out a couple of caps. I am using it with my Bottlehead Quickie-battery powered preamp, ADS L470/2 speakers and a Marantz CD5004. For power supply I am using a 12 volt SLA battery. Lots of fun for the price of a lunch!
 
#600
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