Greetings: Built it last year for a friend. When finished it produced an intermittent whistle type noise in both channels simultaneously which I thought I had solved by taking and applying all your advices set forth in my consultation on this forum at that time. I thought it had been solved by making sure the PCB outer trace where the 4 bolts are, was connected electrically to the chassis.A few days ago my friend brought it to me because the same noise was being produced again in the right channel. It comes on after a few hours of playing time and if I press or touch the chassis it goes away, as well if I press the “tube” case. Later on the whistle starts again....so I’m including photos of the built to see if anyone of you catches something amiss. Thanks in advanced.
Attachments
twisted pairs - newer twist together two channel hots
you can and it is advisable to twist only natural pair of conductors - that being channel hot wire and channel GND wire
so - rewire that thing properly, hoping that susceptibility to oscillation will go down
to ensure that, remove those common gnd wires between RCAs and operate with twisted pairs
you can and it is advisable to twist only natural pair of conductors - that being channel hot wire and channel GND wire
so - rewire that thing properly, hoping that susceptibility to oscillation will go down
to ensure that, remove those common gnd wires between RCAs and operate with twisted pairs
Plus, not certain that the aluminium foil on top of the NuTube is a good idea, as it might be adding capacitive coupling where it's not needed.
