WatKat is a digital "clone" of a Wem Watkins "Custom" Copicat. It sounds very lo-fi, noisy, irregular. When you turn it off and leave the tape loaded, the tape bends in proximity of the capstan, and this turns into a periodic pitch fall during echo playback; plus, it gets hot and the background hum gets worse over time... you should turn it off every now and then; the tape is never completely erased, and the capstan motor flutters... and it gets worse if you touch it while it's spinning; heads tend to get dirty very soon, in fact you should clean them often. This is true for the actual hardware unit, and for the digital simulation as well!