Beftus
100+ Head-Fier
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- Feb 14, 2010
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Weird. Mine doesn't cycle at all. I have a 48VDC 380mA Cisco ADP-18PB.
Weird. Mine doesn't cycle at all. I have a 48VDC 380mA Cisco ADP-18PB.
It's noticeable if you have some kind of power indicator (a LED or pilot lamp). Then you see the indicator pulse a few times before the tubes come up.
cheers!
Quote:
It's noticeable if you have some kind of power indicator (a LED or pilot lamp). Then you see the indicator pulse a few times before the tubes come up.
cheers!
Both my tube LEDs do not blink at power up. The voltage doesn't drop at power up either, it remains steady at 48.3 volts. Perhaps the size of C1 and C6 makes a difference? I used 470uF for those caps instead of the specified 680uF in the BOM.
I will work on it some tonight when I get home. I'll post what I find out later on. I was thinking the same thing about the size of C1 and C6 since I did use the 680uf caps there. How big of a difference does it make to use a smaller cap there?
Considering some of the problems involving the PSU (the power cycling, the capacitance between the PSU ground and true ground = possibility of killing non-protected DAC), are there any possible replacements? Would any 48VDC PSU with a higher current work? Perhaps a modified TREAD? another easy-to-find wall wart PSU?
can anyone explain to me which side of the potentiometer the ground wires are connected to?
wait a second - you mean that the voltage was not equal to 48V when BOTH tubes were unplugged?
And at the same time the unloaded PSU shows 48V? I'm a bit confused. Can you measure the resistance
of the unpowered circuit without tubes? It might be that the PSU has gone crazy so it can't power any reasonable load.
What is the power rating of this PSU? 0.15A? Can you take a separate 350Ohm load (40W light bulb?) and test the
PSU without the circuit?