I've been looking at these things since the little 250.2 came out. And they really piqued my interest when Murilo put them up on sale. For a couple reasons... obviously the size, the name and of course, the price. How do they make them so small? And how can they sell them so cheaply? I don't know, but let's take a look.
Murphy got one for sub duty in the wife's car so he had one on hand. We'll just assume the rest of the line's performance is similar to the 400.1.
They come in this little box. Which I think is just... awesome. Lol. Looks like it could be hanging on the rack at the convenience store. Maybe they should be?
It's really difficult to get an idea of how small this thing really is until you get one in your hands. It's tiny. I love it. No frills. It's just a circuit board in a plexi box. Very cool. I've heard others say the fan is kinda loud. I didn't even hear it so take that for what it's worth.
The input side will seem rather anemic if you're used to 4awg inputs and 8awg outputs from other highs amps, but I actually like these little terminals. All you need is a little micro screwdriver that you probably already have to set your gains. Or, if you're like I am and set your gains with your pocketknife, a teeny tiny flathead is cheap. That's AudioTechnix 10awg speaker wire for power and ground. I don't think much bigger would go. And I think those speaker outs might hold 12awg. Maybe.
Confession... SD's crossovers confuse the crap out of me. There's no selector for LPF or HPF. I ran them both wide open and it made noise so I guess the tones I was playing were in the passband. Was there a manual? Maybe I should have looked at that if there was. Anyone that knows how the hell these work, feel free to chime in; because I'm stuck in a "Wait... wut?" loop.
The "HI" says 5-1khz. I assume that's a 5khz to 1khz high pass filter. The "LO" says 50-20khz. I'll assume that's full range. If that's the case, I was running the "LO" full range, yet high passing at 1khz? I'm lost. Or is that the "HI" range? Perhaps I was low passing everything from 1khz down. Wait... wut?
Anyway... I hooked up the scope unloaded. I was curious about what kind of voltage it was going to make, but all I was getting was millivolts. Either the thing needs a load or I'm a retard and one of the DMM leads came out of the itsy bitsy speaker wire. I suppose we should go with retard there. Either way... this was as "clean" as I could get it. I quote "clean" because it's kinda... fuzzy. But it resembled a round wave. Scope says 28.4v, so let's go with that.
Hooked her up to a pair of D2 subs in series for a 2ohm nominal. Power was supplied by a single G31 batt. Battery power only. HU was an Alpine 9855, volume 28/35 further attenuated by a PAC knob at half. I reckon that's about what normal listening positions would be. It still took very, very little gain to get where we were. I kept the scope on it while clamping, but the battery died half way through testing. I'll vouch for the wave staying "clean" under load even though I didn't get any pics of it in action.
So, using different notes to get different reactive...
5.8 amps & 26 volts = 151w rising to 4.5ohms.
8 amps & 24.5 volts = 251w rising to 3.5ohms.
I drove it into a soft clip and got 6.2 amps & 33 volts = 204w rising to 5.3ohms.
All of these barely got into the battery and were all around 12.7vdc. SD says 400w @ 2ohm @ 12.6v. No doubt that at alternator charging levels or at actual rated impedance, you would get close to 2ohm rated power AFTER rise. That's a good thing.
So, in conclusion... I can't speak for the "SQ" of them since this was only on subs, but I was surprised how loud 250w was on a pair of 12's. I'm a little leery of the fuzziness of the wave but the price is a little too good and the size a little too small not to try some on my highs and get a listening impression. Maybe they lose some of the "clean up" bits to make the 400 watter and the two and four channels are cleaner. I can't see using these on my sub stage. But SD makes bigger amps for that.