Small amplifier--buffered input or not?

[Dr. K]

I appreciate this forum going easy on people new but trying to learn...

I ordered all the stuff for a sequencer, dc power supply, and low-power amplifer build.

I hated my "smokey" amp (386 based). It gives a little cheezy crunch to a guitar, but blech. That's all it does.

So I'm going to build a pair of TDA7052a amps instead.

My question is, I've found schematics with and without a buffered input. Years back I built a buffer because I was using (very high impedance) piezo pickups. I understand the need to use a high impedance input, and a low impedance output.

But with some reading, the transistor buffer here is similar to the one used on the "Smokey" amp, but the schematic from the data sheet for the TDA7052A does not show the buffered input.

I have the parts to build it with a buffer--I'm just wondering, is it ok to use it, regardless of the input impedance? (can I run it all the time, with any device--electronics, piezo or magnetic pickups....). If not, woud it be a good idea to build the buffer stage, and just make it switchable so you can input directy into the chip?

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