Adam Hall, the brand's distributor in Spain, sent us this power amp, which we review below. I'll admit that, even though I try to stay informed about everything that goes on in this business, I knew very little about either the distributor or its products. It's nice every once in a while to have a product you know absolutely nothing about. In any case, it's easy to see that Adam Hall is making a direct, head-on bet on budget gear that brings versatile and, above all, functional equipment to users with smaller budgets.
Four power amp models are available under the LD Systems brand: the PA400 (200 W per channel into 8 ohms), the PA800 (400 W per channel into 8 ohms), our guest, and the PA1600X (700 W per channel into 8 ohms).
LD Systems PA1000
Our guest has no novelties or special features, which doesn't surprise me given its attractive selling price. It's a very conventional design in almost every respect. Class H amplification, with a typical power supply and conventional controls and options, which shouldn't be read as a negative, quite the opposite.
This two-channel power amp weighs almost 20 kilos (about 44 lb) and takes up 4U. According to the specs provided, it delivers 800 W per channel into 4-ohm loads and 500 W into 8 ohms, reaching 1,200 W in bridge mode into 8 ohms. Its THD is rated at no more than 1% (a fine figure, at the limit of the DIN standard at the very least) and the signal-to-noise ratio reaches a decent 110 dB. It lets you select the input sensitivity at 0.775, 1 and 1.5 V (with 1 V the default), and its damping factor is 500 at 1 kHz.
On the rear panel we find a conventional design, with two fans on either side of the connection panel. The panel is one of the most complete as standard: line inputs via XLR or TRS (though without thru outputs to make daisy-chaining the signal between amps easy), power outputs with Neutrik connectors or binding posts, a reset button, and two necessary switches: the bridge selector and the ground lift. On the front we find only (as it should be) the power switch, two limited-travel pots for volume level (one per channel) and three indicator LEDs: power, signal presence and clip warning. Two carrying handles make it easy to install in any prepared rack, thanks to its universal 19" width.
Inside we find a conventional toroidal transformer. The circuitry appears to be fully balanced, which should allow a good signal level throughout the amp as well as a noticeable reduction in noise. Being class H means the operating voltage depends on the signal level. This improves efficiency compared to a class AB amp while also reducing heat. It uses bipolar transistors, which point to a fast, high-performance response. As you'd expect in this type of amp, it also includes a protection system that guards against short circuits, or against impedance dropping below 2 ohms and phase shift exceeding 45º due to reactive loads. There's also a clip-protection circuit, as indicated by the corresponding LED on the front.
But given its price and features, this is an entry-level (or basic) power amp, intended more for low-end systems or applications that don't call for great performance.
And I can confirm that after running the tests.
Put to the Test
Since this is an 800 W per channel amp into 4 ohms, this time I chose JBL's versatile MPRO monitors as the speaker cabinets. They offer a good power-to-performance ratio and should show what our guest can do. That said, the first thing you appreciate, without a doubt, is that the current delivery is quite good. It reproduces the difficult midrange frequencies around 400-1,000 Hz with considerable accuracy without skimping on the highs, although I noticed a certain harshness in them that isn't characteristic of the cabinets used for the listening. Bass reproduction is fairly correct, although it could use a better response, especially in speed, but nothing that can't be worked around. It's one of those amps I wouldn't use, for example, in an active system to drive mid-bass or bass sections, and not just because of its low power rating (you'd need several of them to get good performance across the whole active system). But I would use it, for example, to drive monitors, bearing in mind, of course, the power on offer and the power the chosen cabinet accepts at its nominal rating.
Compared with a Crown CE1000, similar in specs to the amp reviewed here but at a very different price, the differences were (obviously) notable. For starters, the power isn't as good as it seemed to us, although we can fix that with a higher volume level (so the “problem” disappears). On the other hand, that “sluggishness” in recovery becomes more noticeable, since it doesn't achieve the punchy, hard-hitting low end that the Crown delivers in this impromptu comparison. It holds the mids well, and the highs become somewhat brighter, though always at an acceptable level of detail.
The Crown let me work much more with the volume level, allowing a longer and more controlled travel. Our guest in these pages, by contrast, always seemed to demand more, with a response that wasn't very linear. So at low volume levels there was a slight loss of lows and highs, requiring more input level to get the linear response you'd expect from a professional product. I should mention that with a little EQ, most of these minor shortcomings disappeared completely.
But that doesn't mean it should be dismissed, especially considering the price it's sold at. That may be the best thing about this amp and, in a way, it makes up for some of the shortcomings in its design, owing in part to the aim (here we go again) of holding down the final selling price.
Affordable Prices for Professional Applications
Without getting into the tedious (though true) argument that you get what you pay for, it's clear that sometimes it can make sense to have affordable gear for “smaller” jobs, or even as an “alternative” to a high-performance system. Using this PA1000 as a PA amp, even for a low-power rig, may seem crazy. There are amps with the same specs whose results are somewhat better, though the price is higher, and not everyone can afford a big outlay. But there are times when an amp like this can work perfectly, even when we demand quality. For example, for background music in fixed installations where there is solid low-end reinforcement, or as monitors for live rigs where we can manage the small EQ issues described earlier (although its relatively slow response can give us the occasional headache when it comes to controlling the possible “bass buildup” on stage, something inherent in the amp, or rather in what the musicians demand). What can I say when we want to drive, for example, four 10" speakers (ideal for bass players) or, why not, to comfortably drive a pair of monitors, sidefills or even portable DJ cabinets without worrying about the money invested.
Conclusion
For under 600 euros, LD Systems offers a conventional-design power amp with results in line with its price, without exaggerating either one or the other. A more than decent value for the money that should appeal to anyone looking for good gear at affordable prices.
It works within what we expect, though it can't aspire to anything higher. It offers its best potential precisely when the input level asks the most of the amplification circuitry, since that's when you get its best frequency response. At low volume levels the loss of low and high frequencies is somewhat noticeable (sometimes only by comparison), but not a problem that makes our guest unusable.
It also has to be said that it isn't entirely fast, as you'd hope (though understandable given its excellent price), and that it may call for splitting the amplification (and, in passing, building an active system) to keep the low frequencies, the “slow” ones, from losing prominence in our work. A power amp that asks the engineer on duty to be demanding in their work, but that brings professional-world performance within reach at what is, shall we say, a ridiculous price.