RCA Connector input to Headphones/External Speaker

Caution: Please refrain from attempting the following experiment at home without the guidance of a qualified professional like Mr. Oscilloscope. Otherwise, there is a risk of causing damage to your devices.

I was faced with the challenge of connecting headphones to the RCA audio output of my TV, but I had no clue about how to go about it. I pondered over what to do, feeling lost and unsure. To make matters more complicated, the TV I was dealing with was an older model without a dedicated headphone jack. However, I noticed the presence of RCA audio outputs labeled as "Audio Out - L/R." Despite this discovery, I remained clueless about the proper way to connect my headphones to these ports.

All I desired was to witness the captivating display of the signal emanating from the RCA outputs. Fortunately, I had a small homemade oscilloscope at my disposal (though I yearned for a real one). As I directed my attention to the signal on the oscilloscope's screen, I was taken aback by the absence of any signal—only a ground connection. Was that all there was to it?

Determined not to be discouraged, I adjusted the oscilloscope's settings to millivolts (mV). And what I observed was something like this:

Until now, my understanding has been that the RCA output signal is limited to frequencies below 4KHz. Additionally, the signal's oscillation range is between -2.5 mV and 2.5 mV. Unfortunately, this level of magnitude is insufficient for driving my headphones, and even weak for my computer's speaker.

However, I may have found a solution to this predicament. While rummaging through my collection of spare items, often referred to as the "Garbage Box" by my family members, I stumbled upon a few audio op-amps. To rectify the issue, all we need is a clamp circuit and a gain of approximately 1000. This would ensure that our desired signal oscillates between 0 and 5V.

To implement this solution, we require an op-amp that can comfortably accommodate a rail-to-rail supply ranging from 0 to 5V. Ideally, an op-amp from the OPA series audio amplifier would be suitable.

That's it! The following circuit successfully resolved the problem:

Go ahead and try this out for yourself and have a great time!