The Technology of Power

Digital configuration for any signal, any load

PLM™ Series Powered Loudspeaker Management™ systems use the on-board DSP power to offer precise setting of input gain in the digital domain. Gain setting may be actuated from within the control software or via the front panel to optimize performance with any input signal.

In addition, each output channel incorporates a new, digitally implemented version of Lab.gruppen’s proprietary Voltage Peak Limiter (VPL). Renamed the Inter-Sample Voltage Peak Limiter (ISVPL™), this new version in the DSP domain has zero overshoot. New for PLM 20000Q is the software-controlled Breaker Emulation Limiter (BEL™) to avoid tripping mains breakers even with prolonged peak demands and Under-Voltage Limiting (UVL™) that enables continued operation with mains voltage sags as low as 65 V.

Working in tandem with LoadSmart™ and the LoadLibrary™, ISVPL precisely tailors each output for any type of load. No matter what the loudspeaker cabinet type or the arrangement of transducers – from a single massive 2-ohm subwoofer to a series of 16-ohm mid- or high-frequency drivers – ISVPL will ensure the correct calibrated output. Working in concert, the digitally enabled input gain and ISVPL optimize each channel for maximum headroom regardless of input signal dynamics or load impedances.

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 PLM 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 PLM Series power supply also incorporates an enhanced ferrite power transformer core which, compared to its iron core counterparts, dramatically reduces weight and contributes to overall efficiency.

In the PLM 20000Q a new universal (100 – 240 V) Regulated Switch Mode Power Supply (R.SMPS) provides uninterrupted power anywhere in the world.

Class TD® output stage

Lab.gruppen’s PLM Series amplifiers incorporate a power output stage that is literally in a class by itself: the patented Class TD.

Class TD is a breakthrough design that occupied Lab.gruppen co-founder Kenneth Andersson for nearly two years. A patented circuit exclusive to Lab.gruppen, Class TD combines the high efficiency of a digital Class D topology with the sonic purity of classic Class B designs.

With class TD, 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 small portion of this 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 is therefore not subject to the ripple effects of extreme filtering as is necessary with the PWM Class D approach. Class TD is 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.

Though treated separately here, R.SMPS and Class TD were conceived and engineered as an integral design within the amplifier platform. Working together, this new generation of proprietary circuits produces more power from a smaller package while at the same time maintaining Lab.gruppen’s peerless reputation for sonic excellence. The highs stay crisp and transparent. The mids are defined, warm and natural. And the tight low end delivers breathtaking visceral impact.