I-ve done some adjustments to the "power sequencer" ( as you might remember i have an arduino
microprocessor to delay the power-on for the poweramp).
After reading dave gillespies article about "power tube flashing and the reasons"
( http://www.tronola.com/html/maximize_tube_life.html ) i have fine-tuned my power control:
- at startsignal(1) it will delay 3s before powering up preamp. This prevents preamp powersurge if
- after startsignal it will power on poweramp after 25s.
The above delays are unconditional, under no conditions will amps be "power cycled " faster
then this. If power is dropped the startcycle will be repeated from beginning.
When startsignal is removed the poweramp is shut down. After 3s will the
preamp be turned off. This will give poweramp time to unload it's caps and thus be
safe even if the preamp will surge it's output at power off.
If powerdown cycle is aborted and a new startsignal is detected, a normal startcycle is done.
(1) "startsignal" or better named power control signal is a DC > 3V Draws very
little current, could be battery operated.
The arduino itself has it's own PSU, and will at not turn on amps until a complete startcycle is done.
Why ? Just for the fun of it. And, maybe, save some tubes.