Help needed with input jack and Audio amplifier

Thread Starter


Joined May 2, 2010
Hi, I am trying to use an old Sony hi-fi speaker as a guitar amplifier using an audio amplifier circuit with the TDA2030 Hi-fi amplifier.

I have been trying to find out how an input jack is connected to the input of the circuit but I can't find anything. I have attached a pic of the input jack, the lead used from guitar jack to the circuit jack and the amp circuit.

Does anyone know what the 2 solder lugs do and how they are connected? and also is this feasible?

I simulated the circuit on Proteus with a 10mV sine wave and it amplified the signal on an oscilloscope and produced a sound on the loudspeaker model.

I'm not sure of the amplitude of the signal from the guitar and if I will need a pre-amp before the audio amp.



Joined Nov 30, 2010
The long, bent thingy is the signal connector. It shows up as a solder tab on the outside edge. The solder tab in the center is, "ground". 22k is not high enough for a guitar. Try something like 100k ohms or 1 megohm, audio taper, for the volume control, or leave it out and use the volume control on the guitar.

Inside the plug, the long part is the ground and the other solder tab is the signal connection.