That's great news regarding the AC adapter. Thanks for coming back to report.
I picked up one H198 too, daylight only. I think I'm just going to mount it using a standard pin and Superclamp. My hope is that a pair of them will make for decent enough video light that I can set them up as focus assist lights and then toggle to video production when not using my strobes
It is bedtime here but tomorrow I'll set up an H198 next to one of the cheap Cree daylight household bulbs that
I described elsewhere (and also a standard 100 watt tungsten bulb) in reflector fixtures and test the light outputs with my ColorMeter system. At, say, one meter.
We can all relate to how much light a 100 watt bulb in a reflector fixture puts out. If I get a light output comparison metric, anybody can set up however many cheap bulbs in cheap reflector fixtures to see how much light they need. And then see how many H198s would be needed to provide the same output. (Of course with the Cree bulbs I described, that may be all you need.)
Lighting tests are exacting! I did some tests and found out that my ad hoc testing wasn't as repeatable as I thought it was. So here is what I ended up doing. I tested three bulbs. One was a 72w soft white halogen bulb that is rated as being a 100w replacement (these are now legal in the US. Traditional tungsten bulbs were taken off the market because of not being energy efficient). Number two was one of the Cree 100w (equivalent) LED bulbs I had posted about earlier. Number three was an H198 driven by the AC adapter you found on Amazon.
I set up a single Home Depot 5" clamp reflector fixture and swapped the two household bulbs out in the single fixture. I set my ColorMunki up on its side so it didn't move. I measured with a tape measure so the sensor on the ColorMunki was as close to one meter away from the bulbs as I could get it. I did the testing in my computer room so there are whatever random reflections from wood floor and all the stuff in my computer room. (i.e., far from lab conditions. But I did use a tape measure.)
With this said, this is what ColorMeter came up with.

Cree 100w (equivalent) daylight LED

72w (100w equivalent) soft white halogen

Aputure Amaran AL-H198
In the XYZ color space
"Y" corresponds to Lux. So we have
Cree: 405 Lux
Halogen: 384 Lux
H198: 608 Lux.
I did three measurements of each lamp and they roughly agreed. One interesting thing is that the H198 got worse after I left it on. ColorMeter now is giving a "Caution", whereas when I did other tests (right after turning the H198 on) I didn't see the Caution. As of right now, I don't know what the caution means. I used to understand it as meaning that the
Duv (tint away from white) was greater than (abs) 0.0054. But Duv is only -0.0022. I dunno.
We can see that the Cree has more output (Lux) than the Halogen. And the H198 has considerably more.
Here are what the fixtures are:

L AL198, R Halogen bulb in Home Depot clamp fixture
Because of random room reflections we can't consider the measurements as being absolutely accurate but they should be reasonably accurate relatively. I did several rounds of testing, with the ColorMunki being in slightly different positions and they all agreed, relatively. Mostly.
I am a bit concerned about the H198 showing "Caution" after it had been on for several minutes (while I repeated measurements.) The H198's spectrum is less lumpy (after the blue spike) than the Cree bulb. But the Cree bulbs at $9.60 ea. at Home Depot are cheaper than the H198s, especially after adding in AC adapters, Superclamps and what not. But you might not want to show up on a job with a lot of Home Depot clamp fixtures clamped to a mike stand. There is that.
I report, you decide.
Wayne