The Z-30 amplifier, part of the Project 60 range, was launched in November 1969. Both the name and the advertising were somewhat misleading. The adverts (see the gallery on the right) promised "up to 25 watts RMS sine wave (50 watts peak)." In fact, it actually delivered between 15 and 20 watts. And although it promised "true laboratory standards" at "all output levels", in reality it had significant problems with heat dissipation which if it was run at anything approaching sustained maximum power.

These difficulties aside, it was capable of achieving reasonable results if it was not pushed too hard. It was a relatively popular device and sold well, remaining part of Sinclair's audio range until well into the 1970s. It was complemented by the very similar but more powerful Z50 amplifier, introduced the following year.