Yes James I did the stupid mistake thing yesterday. I wanted to try a different ohm setting on the phono in the new Krell pre-amp(new to me). So I unplugged it all took off the lid, changed the dip switches and put it all back. Powered up, but total silence
I struggled round the back to check the connections, still nothing so panic setting in I removed it again and checked inside, all good so put it all back, powered on. No, no, no nothing still.
I was entering melt down phase and then suddenly noticed the Tape knob was pointing to tape not select.
I must have moved it without realising, turned it to select and presto I had sound
Later I noticed a slight hum when not playing music but with had phono selected, not occurring on other inputs. Initially I thought I might have caused it but then I thought well it was not there when using the Sunilda phono stage. I sat down and had a cuppa tea and considered what might cause it. So I thought first this time rather than just unplug it all. Then a light bulb moment, the 90’s Hitachi tuner was sat on top of the Krell pre and but was not on, could it be it was causing the hum. I unplugged the mains to it and instantly silence, joy of joys, the Hitachi had power to its transformer and this was inducing the hum in the phono of the Krell phono.
So I have taken the tuner out of the system for know. The vinyl replay using the Krell phono is now very, very good, so I got there in the end