On Sep 20, 11:24 am, jb-electronics <[email protected]> wrote: > Hi there, > > > On Thu, 20 Sep 2012, threeneurons wrote: > >> Other than brightness, some have observed mechanical 'singing' coming > >> off the larger tubes, like IN-18s. > > > This is the most annoying thing about multiplexing. You can hear the > > in-18 tubehobby kit singing from across a room. > > might also be the switch mode power supply. I have a couple of small > power supplies from TaylorEdge who are remarkably loud. > I have some old B-7971 clocks that are use 1x6 multiplexing at about a 2kHz rate. Even though they are completely enclosed in cabinets madeof 1/4" plexiglass, you can hear them singing up to 10' away in a quiet room. The high speed switching of the high voltages also produces a lot of RFI on the AM and SW bands. It could not be switching noise from the power supplies because these clocks have linear power suppplies, the noise (singing and RFI) is at the mux rate, and you can hear that it is it coming from the tubes.
The clocks have all been running 24/7 for more than 35 years, so if mux'ing reduces the lifetime I have not seen it yet. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
