TEA2025B can I use it as phone amp?

[Hosam]

I have this chip from my old radio in good shape so I wonder how to build a headphone amp from it after I read the data sheet related from ST I just don't know how to start with it any ideas?

 

[pacificblue]

Yes, you can use it. Depending on the impedance your headphones have, you should consider a resistor in series to the phones as protection.

The TEA2025 is rather noisy and in a headphone that will be more obvious than in a radio.

 

[Hosam]

Yes, you can use it. Depending on the impedance your headphones have, you should consider a resistor in series to the phones as protection.

The TEA2025 is rather noisy and in a headphone that will be more obvious than in a radio.

does 10k resistor enough?
for the noisy issue what do you think I should use to filter output
if you think this fair enough I'll try to build it then share the results here

 

[Mooly]

does 10k resistor enough?
for the noisy issue what do you think I should use to filter output
if you think this fair enough I'll try to build it then share the results here

I imagine pacificblue was thinking more in terms of around 47 to 100 ohms.

The IC will work OK, just be sure to follow the recommended minimum gain in the data sheet... in fact just follow the circuit in the ST data sheet but include the output resistors. Make sure you decouple the IC across the supply pins.

 

[Hosam]

at the data sheet they mention the IC has protection for the output with 800ohm resistor then do I need to add more that that for protection?

 

[Mooly]

The 800 ohm is built into the IC to improve performance. You need to add your resistor in series with the headphones (which means adding it in series with the 470uF caps in the diagram). Also it would be wise to add a resistor (say 2K2) from across each output to ground (to ensure the 470uF caps charge before plugging phones in)

 

[Hosam]

sound good tip so I'll apply them then test the result thank you for your help

 

[pacificblue]

for the noisy issue what do you think I should use to filter output

You cannot filter that noise out by any reasonable means. All you can do is try the amp and decide, if you can live with what you hear.

 

[Hosam]

as you said I just try then listen maybe after all its ok and doesn't count as big problem.