My audio interest started with purchase in1976 of a Kenwood KR4600 Amp Technics SL23 turntable and Pioneer HPM60 Loudspeakers. I still have them along with some direct drive Denon with digital readout turntables some of which are slated for refurbishing. One reason for joining was to share some of the components I have amassed over the years - for instance I have over a hundred each of 2N5416 and 2N3439 new old stock which may help some builders. Other interests are building and flying R/C planes both on land and on floats. Building high power inverters (transformer output) up to 12kW just love anything to do with power. In the early 80s I helped create an audio mixer (mostly my own design) for Neumann microphones phantom powered for court room recording. Also to fault find that mixer which when (others) assembled it had lots of hum note: do not ever use the Toroid bolt upper side to anchor an earth terminal for the mains !
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The bolt that runs through a toroid is effectively like a turn of wire in the core and creates a 'shorted turn' if you complete a circuit from top and bottom of the bolt.
The bolt that runs through a toroid is effectively like a turn of wire in the core and creates a 'shorted turn' if you complete a circuit from top and bottom of the bolt.
Hi Mooly - yes I fault found and fixed the issue but it was initially not obvious to find until some thinking was applied, high current low voltage on the Audio return shield cables! The other equipment was earthed separately on the mains so the mains wiring earth was kind enough to return the unexpected current, that was why I mentioned it, a trap for young players ! Oh and thanks for the welcome !