just when I thought that life wasn't complicated as it is. I read "polarity matters when more than one instrument is being played. As a solo instrument, nothing to worry about." "Easy to check polarity.The tip is +. Use a 9v battery and just touch it from the + to - and see which way the cones move.Forward or backwards. Then try the polarity both ways and see which sound you like better." "Another point: phase shift in an amplifier is not absolute - just because you have an odd number of inverting stages does not mean that you have a signal 180 degrees out of phase with the input signal. Every partially-bypassed cathode stage, coupling network, tone stack, and output transformer imparts a frequency-dependent phase shift to the signal. If you take the time to run a phase/frequency plot, you will see that it goes all over the place. In fact, you can make a passive network that will have enough phase shift to give you a complete 180 degrees, so you can have an amplifier with an odd number of inverting stages that actually will produce a signal that is in phase with the input! It won't, however, change the polarity of a transient signal, which will still be inverted."