> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sigbergaudio.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Basic operations

> Amplifier overview, powering on and off, gain and presets on the Sigberg Audio subwoofers.

## Amplifier overview

All connections and controls are on the amplifier panel on the back of the subwoofer. Inkognito uses the Hypex FA251 amplifier and 10D uses the Hypex FA501. The layout of the controls is the same on both.

![Subwoofer amplifier panel with numbered connections, gain knob, status LEDs, select button, mains inlet and power switch](https://mintcdn.com/sigberg-audio/Cql6CMkN3bfpz7D4/images/diagrams/subwoofer-amplifier-panel.svg?fit=max\&auto=format\&n=Cql6CMkN3bfpz7D4\&q=85\&s=eb3b0838e4010b3a90cfc566ded4637e)

> [accordion] Photo: Inkognito amplifier panel (FA251)
>
> ![Photo of the Inkognito amplifier panel](https://mintcdn.com/sigberg-audio/Cql6CMkN3bfpz7D4/images/amplifiers/hypex-fa251.jpg?fit=max\&auto=format\&n=Cql6CMkN3bfpz7D4\&q=85\&s=792a7c4252707b64f7914bd0ce0e3d12)

> [accordion] Photo: 10D amplifier panel (FA501)
>
> ![Photo of the 10D amplifier panel](https://mintcdn.com/sigberg-audio/Cql6CMkN3bfpz7D4/images/amplifiers/hypex-fa501.jpg?fit=max\&auto=format\&n=Cql6CMkN3bfpz7D4\&q=85\&s=86f33e6e4037aaaad3e90da892bfdf0d)

## Powering on and off

We recommend leaving the subwoofer on, unless it will not be used for an extended period of time.

> [!WARNING]
>
> Always make sure the subwoofer is powered OFF before connecting or disconnecting cables.

## Gain

Default position is directly up ("12 o'clock"). The gain can be offset up to 12 dB in each direction from the default position to match the gain of your speakers or power amplifier.

## Presets

3 EQ presets are available to adjust the frequency range of the subwoofer. See [Presets](https://docs.sigbergaudio.com/subwoofers/presets.md) for more information.

Click the **select** button on the back of the subwoofer to switch between presets. The green LED lights marked P1 / P2 / P3 will indicate the active setting.


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