Big bro, the TDA8950

[abraxalito]

No I'll not try out 4 resistors - I get the result I want with only 2. The 'fuzziness' distortion goes away. But I do use an input transformer too on some incarnations - its not absolutely necessary but presents a lighter load when done correctly.

If you're using SMPSUs (recommended due to them having regulation) then get yourself some CLCLC filtering to clean them up.

 

[danielwritesbac]

...board I'm using the two inputs are already wired in parallel. So I went with just two resistors.

In parallel (not anti-parallel). OH, I didn't read carefully enough.

 

[abraxalito]

No, sorry I meant 'in parallel, in anti-phase'. Just as the DS shows for using it in BTL mode.

 

[steffenm]

Hi

I have two of these cheap china modules (TDA8920 and TDA8950) and both have that annoying fuzz. The fuzz and distortion even got louder the more voltagy my toroid had. (less fuzz on 2x13V than on 2x18V) I already tried replacing the pot, different snubbers etc etc. nothing really helped. In my last attemt I tried as suggested earlier in this topic to connect out and input via feedback resistor AND IT WORKED.
Fuzz completely gone, Piano tones are 100% crystal clear. All audible ringing on the outputs is completely gone.

The only thing is: now the channel 1 is about -4db compared to the right channel. Fuzz and distorion is gone on both.
If I try to put another feedback resistor on the second channel, it does not work, the amplifier immediately puts out a DC voltage or the signal gets all crackly.

Attached you can see what I did.
can you tell me what I forgot or what I can do?

 

[dannyjmf]

This: TDA8950 120W 120W Class D Amplifier Board L | eBay Ebay#301442111174

I bought that thing after being impressed with the Sanwu TDA8932 altered to operate in SE mode (it does hi-fi in SE mode, not in bridge mode). And, big bro, the TDA8950, as presented by eBay has a visible flaw at the onboard power supply but no other obvious flaw. It seemed to need the one thing I'm good at, a fair linear supply system.

On first start-up, I was floored. Yes, I could hear the little obvious taint from the cheapest on-board power supply ever designed. However, that wasn't as bad as I thought it would be, and it doesn't sound like a Class D amplifier. It just sounds like a really good amplifier that might could use a better supply. I had not expected the factory condition to be either pleasant or relevant. However, it is both. This a fantastic surprise! This a cheapskate midfi, but as such it has done its job far better than expected.

It sounds a lot like little bro, except cheaper and more headroom.

Unlike its slightly better? little brother, the bigger job this thing does is expensive; so much that comparison is not really valid except for fun. This amp does $300 worth of fun at less than $40. It isn't that you couldn't get better, but rather that this amp defeats the scammers so thoroughly that you don't need to spend too much for nearly high end audio.

Therefore, the remainder of this thread should be be about increasing the resolution of this amplifier. Let's see what happens.

hi ... daniel ... i would like to seek for advice ... i am currently using the tda8950 class d amplifier module too at the time being. But a basic comparison through listening test seems like my LM1875 gainclone gives better sound compared to TDA8950. What is your comment over here? .... For your information i am currently planning to change my system to active biamp thinking to use the TDA8950 for the mids and LM1875 for the highs? or both using TDA8950 for mids and highs?

thanks

 

[dannyjmf]

Hi

I have two of these cheap china modules (TDA8920 and TDA8950) and both have that annoying fuzz. The fuzz and distortion even got louder the more voltagy my toroid had. (less fuzz on 2x13V than on 2x18V) I already tried replacing the pot, different snubbers etc etc. nothing really helped. In my last attemt I tried as suggested earlier in this topic to connect out and input via feedback resistor AND IT WORKED.
Fuzz completely gone, Piano tones are 100% crystal clear. All audible ringing on the outputs is completely gone.

The only thing is: now the channel 1 is about -4db compared to the right channel. Fuzz and distorion is gone on both.
If I try to put another feedback resistor on the second channel, it does not work, the amplifier immediately puts out a DC voltage or the signal gets all crackly.

Attached you can see what I did.
can you tell me what I forgot or what I can do?

aha a good post here ... i too having the annoying buzz with my TDA8950 amplifier module. Dont mind can you show me how you physically modified the amplifier? i mean the add on resistor how you connected it? thanks

 

[steffenm]

sure ca do