When I saw this listing, I couldn’t help but think “What a cool idea!”. An inverting audio amplifier with potentiometer adjustment in a DIP-8 ready-to-breadboard package! This would be so handy when prototyping any audio-related projects. No matter what, you seem to always need some gain along the way, and being able to just plug in a ready-made solution will save breadboard space and prototyping time.
By placing all the components in the same footprint as a DIP-8 op-amp, you get all the functionality without having to calculate and add all the external components necessary. Delivering anywhere from +/-20dB of gain (yes, it can attenuate as well as amplify!), this inverting op-amp is perfect when used as a final amplifying stage, as a pre-amp driving some other circuitry, or even just as inter-stage gain steps between successive effects.
It does require a bipolar supply. A simple way to get a very clean, stable bipolar supply is to use two 9V batteries, with the negative terminal of one connected to the positive terminal of the other. This works as your “ground” or reference voltage, and then you are left with exceptionally noise-free +/-9V supplies for op-amps and other circuitry (thanks to Ben Krasnow for this tip!).
The documentation is very clear and well-designed, with easy-to-read schematics and pinouts. The included op-amp isn’t specified but it’s likely something along the lines of a TL081 or a similar high-quality audio op-amp. Having building-block parts like this in your drawer can make prototyping and testing so much simpler, and knowing that it just works can reduce headaches when something does go wrong!