Velodyne F1500R with (apparently) broken amp (1 Viewer)

So my F1500R, which I love, no longer makes any sound. The power light is on, and the transformer gets hot, but that's it. I took the amp out, and there is nothing obviously fried, but something is clearly no longer functional. Velodyne no longer supports the amp, but cheerfully gave me the schematics. It's a bit out of my league to fix though, without an obviously blown cap or something.


Coincidentally, I also happen to have a Rotel RMB-985 with one bad channel sitting there unused. That's 4 additional channels of 100W RMS power, Is there any reason I can't use one of those channels (amp does not appear to be bridgeable, unfortunately) to power the sub? It's less than half the power of the Velodyne amp, but I don't need to shake my foundation, the original amp through that sub was LOUD. I rigged something for testing, and it technically worked, but was far quieter than it should be with 100W RMS. Anyone try something like this?

It's less than half the power of the Velodyne amp, but I don't need to shake my foundation

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Cutting the power in half lowers the maximum potential output by only 3db theoretically. In reality, it's not that much.

I rigged something for testing, and it technically worked, but was far quieter than it should be with 100W RMS.

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Could be that you don't have the amp gain turned up enough.

Anyone try something like this?

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Passive sub with an external amp? I do. I use a Behringer EP-2500 (current model is the identical EP-4000) to power a pair of 15" TC Sounds TC-3000 15" subs. It's nothing new. A lot of the people who build their own subs use pro amps to power them. Price per watt is low and these amps provide a LOT of power. Via independent testing, mine will push about 825w per channel into 2 ohms. That's how I have each TC-3000 sub configured. You can get larger amps as well. I've read where some guys are using 5,000w amps but that requires 220v/40amp amp circuits.

I guess my question about anyone trying this was intended to be more specific, as in, has anyone tried something like this with a Velodyne servo sub or similar? I really don't know how all their accelerometer and feedback circuitry impacts the equation. I suppose it's possible that the point at which I was attaching the amp output was not optimum, or maybe the driver is a higher impedance than "normal" (although I read something somewhere that indicated it was 6-7 ohms, which should be fine for the Rotel). And of course, you're absolutely right about the gain...it is highly likely I didn't have that set high enough.

Without the accelerometer connected the driver is a plain sub driver. Nothing special about it.