- Published in issue 7/1997 on page 103
AF input selection
Input selection in the battery operated preamplifier published in the January 1997 issue of this magazine is by rotary switch. This does not give the best possible performance as far as cross talk and channel separation are concerned. This article proposes a better means, which also enables the number of input to be extended to 12. In this design, each input source is linked to the circuit via a bistable relay (described elsewhere in this issue).