I’ve got the scorpion up and running now with it bolted to a 1/4” bar of aluminum.
The heater voltage seems solid, but I’ve got HV2 cranked as high as it will go, and under load it stops at 256V. I’ve got 266V unregulated at the power resistor and 116VAC at the outlet (USA).
Does this seem correct under load?
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With no load attached do you get about 310vdc unreg ?
Is there one or two of the tube preamps in the schematic attached to the scorpion when you get those voltages?
With nothing connected to the PSU I have 306VDC unregulated and the regulated supply jumps up to 296VDC. Both HV1 and HV2 have the same issue, when the Filament is connected they won't go higher than ~256VDC
With nothing connected to the PSU I have 306VDC unregulated and the regulated supply jumps up to 296VDC. Both HV1 and HV2 have the same issue, when the Filament is connected they won't go higher than ~256VDC
Ok that is a bit low. Does it go to 320v with no filament attached?
The filament is set to 12v? and 48v to 48v ok?
The correct tubes are fitted?
The 3ma of the HV shouldn't sag the voltage that much.
Let me know the answers above and I will do some calcs to see what is going on.
There is no filament connected with those previous voltage measurements.
The filament is set to 6V right now. These are the original tubes to the preamp. The 48V seems fine. Haven’t put a load on it though
The schematic for the mic pre you put up showed 12v filament as the 2 tubes are wired in series. Is that correct? 12v 330mA ? or are they wired in parallel 6v @ 660mA? 12v is the much better option heat-wise.
I would get the power supply running the correct filament and then let me know the unreg hv voltage with the filament connected.
Also a couple of photos of the top and bottom of the pcb build and heatsink would help to double-check things.
