Leema Hydra II Anniversary Power Amplifier

Leema Hydra II Anniversary Edition power amplifier is a special version of the already well regarded standard Hydra II model. The Anniversary edition of Hydra II features several key upgrades. These include a PCB with twice the amount of copper for improved signal transfer. Capacitors have been upgraded to Nichicon high-quality audio-grade MUSE series devices.

Additionally, the speaker cable from the board to the output, now uses Leema’s reference 2 cable. This has silver plated conductors. Moreover, the transformers are made by Noratel, and are their extra quiet units. Finally, each amplifier has a passport style check document, that is signed at every stage of production, along with a performance results report – to ensure each unit has been measured as optimal as possible.

Build quality

The design of the Hydra II is modern without being overpowering. The Aluminium front panel is balanced by the heatsink grills that sit at either end. Additionally, a ring of blue LEDS indicates the volume level. Air vents on top of the case are drilled in the shape of the Leema logo. Inside two circuit boards are used for the monobloc amplifier modules. This separates them both, physically and electrically, for maximum channel separation. They also have individual power supplies.

Remarkable connectivity

The amplifier inputs are selectable between balanced XLR and conventional RCA sockets. Notably there are a number of setup switches on the back. These are used to indicate whether the unit is in stereo mode or left or right monobloc mode. A set of switches is also used to indicate whether the unit is in Surround mode, fixed gain or to be controlled with the LIPS system. Standard speaker connectors are used at either end of the case.

Bridgeable stereo amplifier

For even more power the Hydra II Anniversary edition can be doubled up and individually bridged. This will provide close to 400 watts per mono unit. They can be used in multiples for a surround system. The configuration can be set using Lemma’s LIPS system control bus.

The LIPS control system

All Leema devices can communicate with each other by using the LIPS Bus. LIPS stands for Leema Intelligent Protocol System. For example, once the configuration of Hydra II is set, the Preamp will know whether the Hydra II is to be used in stereo mode or as one channel of a surround system. The bus can also control the volume and source select. The Lips system uses a 3.5mm plug fitted lead, for communication.

Balanced inputs

Like most high-end amplifiers the Hydra II has balanced inputs. These use more robust plugs than RCA connectors and are electrically balanced. RCA connectors use only two conductors this makes them prone to noise pickup. Additionally, the plugs can corrode and start to give intermittent contact. That is why some are gold plated. On the other hand, balanced leads use studio grade XLR connectors. These have three leads, a hot or positive wire as well as a negative or cold wire. There is also a zero volts reference or ground wire.

Balanced leads work by providing an anti-phase signal on each of the main wires. An audio signal swings both positive and negative, with respect to the zero volts reference or ground. That is why amplifiers such as the Hydra II Anniversary Edition have output protection, as a transistor short can put a high voltage across the speaker, destroying the voice coil. With a balanced lead the anti-phase signals cause noise to be cancelled out. This gives a much cleaner signal path. The main reason why they are used in studios, especially for microphone leads.