Tube life can be extended if you delay the application of high voltage until after the heaters have warmed up and current can flow. This little module does just that: depending on the setting of a jumper, it delays the high-voltage for 40 or 60 seconds after the amplifier is switched on.
It can easily be retrofitted to any amplifier because it is wired in between ground and the power transformer center tap (or between ground and the bridge in a full-wave rectifier). It needs a floating heater winding or equivalent to power it. The small PCB and the controller chip are now available online on Linearaudio.nl - Jan Didden’s website - where you can download Gerber files that should be useable by any reputed board house, as well as download the Hex file for the controller firmware.
This article was originally published in audioXpress, February 2014.
Read the full article here.