18w amplifier using tda2030

[iitsanup]

hi ,

i have build an amplifier circuit using tda2030 as in the attachment , but i have done only stereo part and not the sub woofer.

now the thing is the amplifier is working fine only if i increase/ decrease the volume of one side(LHS/RHs) if i do the both a craking noise comes. pls help me. i want to listen in both speakers.


 

[grumpydoc]

I'm not sure what your problem is.

Do you have a dual-gang potentiometer for the volume control or two single-gang ones?

Do you mean that you get a crackling sound as you turn the volume control (which then stops when you stop turning the volume control?

If so then a dry joint on the pot might be the cause. Or a DC potential across the track although if you have built the circuit correctly this should not happen as there is a capacitor to block any DC.

Do you mean that you hear crackling distortion when both channels are in operation but not if only one has the volume turned up?

If so then I'd look at the power supply - a single 7812/7912 is a bit marginal for a TDA2030 and I think inadequate for two or three as it is a 1A regulator. You might find the supply voltage is dropping low and you are getting clipping when that happens.

Or do you mean something else?

[dr_p]

If both channels work at low volume, but not at full power, check the power supply. I suspect that as the current consumption increases, the ripple is getting higher, reaching too low of a voltage for the TDA2030 to output the required power. Measure AC voltage on the filter caps or put a scope on it. If it's the case, increase the size of the filter caps.

BTW, do you need regulated +/- 12V for the op-amps? Where did this schematic come from? I'm just curious.
@grumpydoc: only the op-amps are regulated(V+ and V-), the TDA2030s get the VDD ans VSS

[grumpydoc]

@grumpydoc: only the op-amps are regulated(V+ and V-), the TDA2030s get the VDD ans VSS

Missed that, thanks.

We both agree it sounds like the PSU is the probem. I think it's worth the OP making sure that he's not feeding the TDA2030 from the regulated supply and that his transformer is adequately rated.