Breakthrough Technology, Upgraded for FP+
A Tradition of Craftsmanship
Every FP+ Series amplifier is designed, engineered, assembled, and rigorously tested at Lab.gruppen’s manufacturing facility in Kungsbacka, Sweden. The uncompromising dedication to quality and craftsmanship is evident in every detail.
Regulated Switch Mode Power Supply (R.SMPS™)
Lab.gruppen pioneered the use of switch mode power supplies in power amplifiers, and the latest generation of this technology plays a key role in enabling the extreme power density of the FP+ Series. Precise regulation maintains constant voltage on the internal rails, ensuring full output power and undistorted sound even when the mains voltage drops as much as 20% below nominal. The FP+ power supply transformer incorporates an enhanced ferrite core which, compared to iron core transformers, dramatically reduces weight and contributes to overall efficiency.
Class TD® output stage
Lab.gruppen’s FP+ Series amplifiers share an output stage that is literally in a Class by itself: the patented Class TD. A breakthrough design that occupied Lab.gruppen’s co-founder Kenneth Andersson for nearly two years, Class TD combines the high efficiency of a digital Class D with the sonic purity of classic Class B designs.
The power supply rails precisely track the audio signal at all times, providing the required voltage plus additional headroom. This process is highly efficient, with only a tiny portion of the supplied voltage emitted as heat in the output stage. The audio path itself remains entirely in the analog domain: it never enters the switching portion of the circuit, and therefore is not subject to the ripple effects of the extreme filtering required by the PWM Class D approach. Class TD is bridgeable, highly reliable, and maintains a flat response with complex loads as low as 2 ohms nominal. Also, it does not interfere with RF equipment such as wireless (radio) microphones.
Intercooler® for efficient, uniform cooling
The compact and ultra-efficient Intercooler uses thousands of tiny cooper cooling fins to increase exposure of the heat sink to the cooling air flow. Twin variable-speed fans respond to temperature sensors, forcing air over the Intercooler fins in a front-to-rear flow. All output devices are mounted transverse to the airflow, so the cooling effect is uniform. There are no “end of tunnel” output transistors subject to greater warming and, consequently, possible premature failure.
Configurable for any signal, any load
Each FP+ amplifier offers an eight position input gain switch to optimize performance with any input signal. In addition, each channel incorporates Lab.gruppen’s exclusive Voltage Peak Limiter (VPL™) circuit.
VPL precisely tailors output for any type of load, from a single massive 2-ohm subwoofer to a series of 16-ohm mid- or high-frequency drivers. Working in concert, adjustable input gain and VPL optimizes each channel for maximum headroom regardless of input signal dynamics or load impedances.
A full suite of protection features
Lab.gruppen’s FP+ Series incorporates comprehensive warning and protection features to protect the amplifier and any connected loudspeaker drivers. Front panel indicators and the DeviceControl GUI give clear warnings when any potential problems are detected.
Protection measures are enabled only when critical thresholds are passed: measurements are re-checked every few seconds, and normal operation resumes automatically when nominal conditions are restored. The complete protection/warning suite includes: DC at output, short circuit, excessive output current, sustained very high frequency (VHF), and open load.
The FP+ Series also includes features to guard against inadvertent tripping of the mains fuse or external circuit breakers, either during a performance or at start-up. While in operation, a Power Average Limiter (PAL) constantly monitors the current-drawing relationship between the power supply and the mains inlet. If conditions are detected where the power amplifier could draw more than the mains inlet can supply, PAL limits current draw to prevent power interruption. Additionally, a soft-start circuit limits initial current draw when amplifier is turned on.