Sinclair ZX80 / ZX81 / Z88 Forums

Well, here's a photographic step-by-step tutorial for dummies, for the 50mV MIC modification as I successfully did it yesterday! I hope it helps EVERYONE who owns a Zeddy to easily improve the quality of its MIC output, this is really useful! Just follow the steps respectively to the 5 numbered pics...

With all due respect to Siggi who is a true zeddy guru but in his description he says that a louder output is achieved whilst retaining the same filter characteristics by using a passive resistor capacitor circuit. In all my years of audio amp and tone circuit construction unless active elements ar...

Some 20 years ago there has been published a small modification to the ZX81 to give a louder MIC output signal. The modification was to solder a new R/C circuit in parallel to the original one (R29/C12) to give a higher output signal, while maintaining the filter caracteristics (the values for the ...