The MA-5002VZ is a power amplifier from Crown’s famous Macrotech line, which has been used for many years to power some of the most powerful rigs ever built. Macrotechs have always been known for delivering very stable high power and for being able to work into fairly low impedances. This amp also belongs to Crown’s new VZ (variable impedance) series, which lets it adapt dynamically to the signal and to the power required, in real time and to both at once. Obviously, the biggest difference between this amp and the others we’ll be looking at is that it is not digital, so its size and weight are considerable given the power it delivers. We are therefore looking at a unit that weighs 35.2 kg and takes up three rack spaces.

Technical Specifications
This amp delivers 1,300 W per channel at 8 ohms, 2,000 W at 4 ohms and 2,500 W at 2 ohms, per channel and measured at 1 kHz. In bridge mode (bridging the two halves of the amp to get a single, more powerful output) we get 4,000 W at 8 ohms and 5,000 W at 4 ohms, also measured at 1 kHz.

Input impedance is greater than 10 kohms for a balanced signal and greater than 5 kohms for an unbalanced signal.

Input sensitivity can be set to 0.775 V or 1.4 V for standard power at 1 kHz, or to a voltage gain of 26 dB.

As a quick theory refresher: voltage gain is the result of dividing the output voltage the amplifier produces by the input voltage it receives; in other words, how many times it amplifies the incoming signal.

Voltage Gain = Output Voltage
/ Input Voltage

To convert it to dB, we multiply the log of this gain by 20:

Voltage Gain (dB) = 20 x log (Output Voltage / Input Voltage)

For example, this amp working at 8 ohms with a 1 kHz signal gives us:
With a sensitivity of 0.775 V, a voltage gain of 132X, or 42 dB.
With a sensitivity of 1.4 V, a voltage gain of 71X, or 37 dB.
With a sensitivity of 5 V, a voltage gain of 20X, or 26 dB.
This means the amplifier boosts the input signal by 42 dB, 37 dB and 26 dB respectively, up to the maximum power it can deliver, of course.

The signal-to-noise ratio is > 105 dB, measured at 1 kHz.

The amp’s inputs can be XLR or balanced jack, and the outputs are larger-than-usual binding posts that accept high loads and let you use spade terminals, banana plugs or bare wire directly.

The damping factor is greater than 1,000 from 10 Hz to 400 Hz.

Here is a bit more theory on this as well. The damping factor is the amplifier’s ability to control the reactive energy of the loudspeaker. Let’s look at it in more detail. When an amplifier sends a signal to the speaker, the speaker moves forward or backward. Because the speaker is a mechanical system with mass (weight), it has inertia. This inertia makes the speaker cone keep moving after the amplifier’s signal is gone. When this happens, the speaker’s voice coil, moving over the magnet, generates an electrical current (this is the same way a dynamic microphone works). In fact, if you put a voltmeter across the terminals of a low-frequency driver and move the cone by hand, you’ll see a voltage generated across the terminals. This voltage reacts against whatever is connected to it: the amplifier. When the amplifier is sending signal, that signal is constantly affected by the speaker’s reactive energy. The more control the amplifier has (the higher the damping factor), the less this reaction affects the signal. The damping factor can be calculated, and it takes into account not only the amplifier’s actual output impedance (that of the circuit), but also the impedance of the cable being used.
So the heavier the cable gauge, the higher the damping factor, and vice versa. The formula for calculating a system’s damping factor is the speaker impedance divided by the impedance of the system driving it (cable plus amplifier). For example, if I have an 8-ohm speaker and an amplifier with a damping factor of 600, dividing 8/600 gives me 0.0133. That is the amplifier’s actual output impedance. Now suppose this speaker is connected with a 2 mm cable that is 15 meters long. Looking at the tables, we find this cable has a nominal impedance of 0.005 ohms per meter. Since our cable is 15 meters long, the total impedance will be 0.005*30 (the cable goes out and comes back, so it’s 30 and not 15). That gives me 0.15. I add this to the amplifier’s actual impedance (0.0133) and get 0.1633. This is the actual impedance of the system feeding the speaker. The system’s damping factor will then be 8/0.1633, or 48.98. As you can see, the amplifier’s damping factor is affected by the cable’s (from 600 we drop to 48). With a thinner cable the situation is far more drastic, and this is why heavy-gauge speaker cables are recommended. As a general rule, you want the system’s damping factor to be above 10.

That is why, with amplifiers this powerful, the goal is for the damping factor to be as high as possible, since the movement we’re going to impose on the speakers will be very large and we don’t want their reactive energy to affect the original signal too much.

This amp has one compressor per channel, adjustable to three positions: Fast, with a 4-millisecond attack and a 300-millisecond release; Slow, with a 12-millisecond attack and a 600-millisecond release; and Off.
It also features the patented ODEP system, which proportionally adjusts the level according to the loudspeaker in order to protect the output transistors, and which, in the event of high temperature, temporarily cuts the output until the cooling system brings the channel back to an acceptable temperature.

It also has a power supply that automatically adjusts to the input voltage, so it can work anywhere in the world.

Pros and Cons
This is the most powerful non-digital amp Crown makes, which at first glance means we have to consider its high weight and size. Even so, we shouldn’t overlook the fact that, throughout its long career building analog amplifiers, Crown has always given us very robust and very reliable units. For a brand like this, a pioneer in power amplifier manufacturing, it’s only natural that every top-of-the-line product it offers lives up to the demands we might place on it.

Connectivity is simple and versatile, keeping the signal balanced even on the jacks, although on the outputs we miss Speakon connectors, which are currently the most widely used connector on most loudspeaker enclosures.

The advantage of using an “analog” amp over most digital ones is that the price is lower. That said, this particular model costs more than other digital amps that deliver the same power, but of course those don’t come from a company with such a good name and such wide recognition among all sound engineers.