So this has taken an awkward turn.
My computer speakers, multiple server power supplies, and my subwoofer amp all died within days of eachother. Everything except the sub was on UPS. Everything is about the same age. Not sure if coincidence or not.
So I advised the above and modified the X-530 for external transformer. Very easy.
The server was already getting replaced by NAS, so that's already done and dealt with.
My subwoofer...different story.
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I pulled the amp out of the cabinet tonight. I only see one cap that is bulged out, and it's a small 470uF one at that.
I unplugged the feedline, and my multimeter is showing 6.0 to 6.2 ohms Re. Which provides some bafflement...because it's definitely without question wired in parallel.
I unplugged one voice coil, and the output did not change. Further prodding is showing 6 ohms on one coil and infinite ohms on the other. Which sucks.
An old white paper I found on the DIY forum titled "Adire Shivas: Anyone remember version differences?" Shows the following for the Shiva mk3:
Re: 2.9
Z: 4
Le: 2.12
This makes sense for mine being dual 8's, which would be 5.8 ohms Re per coil.
Long story short, my Cerwin Vega CVT-300S from 15 years ago has a bad power side, ad it has a constant hum that I can't seem to kill.
Along the way of diagnosis, I found that one of the 2 voice coils in my likewise 15 year old Adire Audio Shiva has an open in it.
My enclosure is very large and tuned subsonic, almost behaves like an IB.
I have been talking to the new owners of Adire, and I'm all but ready to turn the key on a 15" tumult. They can't recone the old shivas for whatever reason and I can't fault them for that.