CA-3316A 100W Subwoofer Amplifier TPA3116D2 IC Inbuilt With Volume Control And Frequency Control Pot

Key Features

• TPA3116D2 Class-D amplifier IC

• Dedicated mono subwoofer amplifier

• Up to 100W maximum output

• DC 12V–24V operating range

• 24V / 5A recommended for higher-output operation

• 2Ω–8Ω passive subwoofer compatibility

• Adjustable 20Hz–180Hz low-pass frequency range

• Independent subwoofer volume control

• Independent frequency/cut-off control

• 
  

  90% stated efficiency

• 100dB stated signal-to-noise ratio

• Integrated heat sink

• Compact PCB design

• Screw terminals for power and speaker connections

• Suitable for modular 2.1-channel systems

Electrical Specifications

Audio Specifications

Mechanical Specifications

Protection Features

The current RoboGears listing specifies protection against:

• Over-voltage

• Under-voltage

• Over-temperature

• Short circuit

Protection circuitry provides an additional safeguard but does not replace correct power-supply selection, polarity, speaker matching and ventilation.

Understanding the 100W Rating

The 100W specification represents the amplifier's maximum published output capability under suitable conditions.

For higher-output operation, RoboGears recommends:

24V DC / 5A

Using a 12V supply is supported, but the available maximum output is substantially reduced.

Actual output depends on:

• Supply voltage

• Available supply current

• Speaker impedance

• Audio input level

• Thermal conditions

• Wiring quality

Do not interpret the 100W figure as guaranteed continuous output under every operating condition.

Compatibility

The CA-3316A is designed specifically for:

1 × Passive Subwoofer

It provides a:

Mono Low-Frequency Amplified Output

Subwoofer Compatibility

Published speaker impedance:

2Ω–8Ω

It can be used with compatible passive:

• 2Ω subwoofers

• 4Ω subwoofers

• 6Ω subwoofers

• 8Ω subwoofers

The subwoofer's power-handling capability should also be suitable for the intended amplifier output.

Power Supply Compatibility

Supported operating range:

DC 12V–24V

For higher-output applications:

24V / 5A

is recommended.

Lower-voltage supplies can be used within the supported range but will reduce the maximum available output.

Audio Source Compatibility

The amplifier accepts a suitable analogue audio input and can be integrated with:

• Bluetooth audio receivers

• MP3 decoder modules

• Pre-amplifiers

• Tone-control boards

• Computers

• TVs with suitable analogue output

• Smartphones with suitable analogue output/adaptor

• Existing audio systems with compatible line-level output

Building a 2.1 System

The CA-3316A handles the subwoofer channel only.

A modular 2.1 system can therefore use:

Stereo Amplifier → Left + Right Speakers

and

CA-3316A → Subwoofer

from a suitable shared or distributed audio source.

Important — This Is Not a Stereo Amplifier

The CA-3316A provides:

1 × Mono Subwoofer Output

It does not provide:

Left + Right amplified stereo outputs

If you need one board to directly power left, right and subwoofer speakers, choose a dedicated 2.1-channel amplifier board instead.

Required for a Working System

You will generally need:

• CA-3316A amplifier

• Passive subwoofer

• Suitable DC power supply

• Audio source

• Audio input wiring

• Speaker wiring

Optional Additions

Depending on your project:

• Bluetooth receiver

• Stereo amplifier

• Audio pre-amplifier

• Power switch

• Enclosure

• Input connectors

Before Purchase

Amplifier: TPA3116D2

Configuration: Mono

Purpose: Subwoofer

Output: Up to 100W

Supply: DC 12V–24V

Recommended High-Output Supply: 24V / 5A

Speaker Impedance: 2Ω–8Ω

Frequency Control: 20Hz–180Hz

Stereo L/R Outputs: No

Bluetooth: Not built in

Applications

• DIY powered subwoofers

• Home-theatre bass systems

• 2.1-channel audio projects

• Desktop speaker subwoofers

• Bookshelf speaker + subwoofer systems

• Wooden subwoofer cabinets

• Multimedia speakers

• Workshop audio

• Custom speaker builds

• Portable DC audio systems

• Audio prototyping

• Educational audio projects

Suitable For

• DIY audio builders

• Speaker builders

• Electronics hobbyists

• Engineering students

• Makers

• Audio technicians

• Home-audio projects

📦 What's Included

❌ What's Not Included

The standard package does not include:

• Passive Subwoofer / Woofer

• DC Power Supply

• Speaker Cable

• Audio Input Cable

• Bluetooth Receiver

• Stereo Amplifier

• Left / Right Speakers

• Subwoofer Enclosure

• Power Switch

• AC Power Cable

Important Purchase Note

This product is a subwoofer amplifier board, not a complete powered subwoofer.

For a basic working system you will need:

Audio Source → CA-3316A → Passive Subwoofer

and:

12V–24V DC Power Supply → CA-3316A

For higher-output applications:

24V / 5A

is recommended.

Building a Complete 2.1 System

For left, right and subwoofer reproduction:

Audio Source

↓

Stereo Amplifier → Left + Right Speakers

and

CA-3316A → Passive Subwoofer

A separate stereo amplifier is therefore required unless your system already has amplified left/right channels.

Product Variation

PCB colour, heat-sink appearance, capacitor brands, potentiometer style and minor component placement may vary between manufacturing batches while maintaining the intended CA-3316A functionality.

Getting Started

Step 1 — Select the Subwoofer

Use a compatible passive subwoofer within:

2Ω–8Ω

Make sure its power-handling capability is appropriate for your intended listening level and amplifier setup.

Step 2 — Select the Power Supply

Supported supply range:

DC 12V–24V

For higher-output operation:

24V / 5A

is recommended.

Do not exceed 24V DC.

Step 3 — Set Both Controls Low

Before first startup:

• Reduce volume

• Set the frequency control to a moderate/low position

This provides a safer starting point for initial testing.

Step 4 — Connect the Audio Input

Connect a suitable analogue audio source to the amplifier input.

For longer installations, shielded audio wiring can help reduce unwanted noise and hum.

Step 5 — Connect the Subwoofer

Connect the passive subwoofer to the amplifier's speaker-output terminals.

Follow the markings on the actual PCB.

Step 6 — Connect the DC Supply

Before applying power, verify:

• Correct voltage

• Correct polarity

• Secure power connection

• Correct speaker wiring

• Correct input wiring

• No loose strands or short circuits

Step 7 — Apply Power

Power on the amplifier.

Check for:

• Abnormal heating

• Smoke

• Unusual smell

• Unexpected speaker noise

Step 8 — Start Audio Playback

Begin at a low audio level.

Gradually increase the volume after confirming correct operation.

Step 9 — Adjust Subwoofer Volume

Use the Volume control to balance the subwoofer level with the rest of the audio system.

Avoid simply setting the control to maximum.

Step 10 — Adjust the Frequency Control

Use the Frequency control to adjust the low-pass cut-off.

Published adjustment range:

20Hz–180Hz

A lower setting concentrates the subwoofer on deeper bass.

A higher setting allows more upper-bass frequencies through.

The best setting depends on:

• Subwoofer driver

• Enclosure

• Main speakers

• Listening environment

• Personal preference

Understanding the Two Controls

🔊 Volume

Controls the overall subwoofer output level.

Use it to balance the bass with the main speakers.

🎚 Frequency

Adjusts the low-pass frequency/cut-off.

This determines how much of the upper bass range is passed to the subwoofer amplifier.

Basic Subwoofer Setup

Audio Source

↓

CA-3316A

↓

Passive Subwoofer

and:

12V–24V DC Supply → CA-3316A

Modular 2.1 Setup

Audio Source

↓

Stereo Amplifier → Left + Right Speakers

and

CA-3316A → Subwoofer

Installation

When installing inside an enclosure:

• Secure the PCB mechanically

• Keep the heat sink ventilated

• Avoid contact with conductive surfaces

• Use appropriately sized power wiring

• Keep signal wiring away from high-current wiring

• Keep the two controls accessible if future adjustment is required

🔧 Prototyping and Engineering Tips from RoboGears

1. Use 24V / 5A for Higher-Output Builds

The amplifier can operate from 12V, but available maximum power will be substantially lower.

For builds intended to approach the board's higher output capability:

24V / 5A

is the recommended starting supply.

2. Use an Actual Subwoofer Driver

This amplifier is designed specifically for low-frequency reproduction.

Use a dedicated woofer/subwoofer rather than expecting a small full-range speaker to reproduce high bass power effectively.

3. Tune the Frequency Control

Do not automatically set the frequency control to maximum.

Adjust it until the subwoofer blends naturally with the main speakers.

4. Start Around the Main Speaker Roll-Off Region

If your main speakers already reproduce substantial bass, a lower cut-off can help prevent excessive overlap.

If your main speakers are small and lack bass, a somewhat higher setting may provide a smoother transition.

Final adjustment should be done by listening to the complete system.

5. Balance the Subwoofer Volume

More bass is not always better.

Set the volume so that the subwoofer supports the main speakers rather than overpowering them.

6. Use a Clean Regulated Supply

A poor-quality power supply can introduce:

• Hum

• Buzz

• Switching noise

• Distortion

A properly regulated DC supply is recommended for audio applications.

7. Use Shielded Audio Wiring

Low-frequency systems can make mains hum particularly noticeable.

Keep signal wiring:

• Short

• Shielded where practical

• Away from AC mains wiring

• Away from high-current DC wiring

8. Keep the Heat Sink Ventilated

Class-D amplification is efficient, but heat is still generated at higher output levels.

Do not completely block airflow around the heat sink.

9. Use Suitable Power Wiring

Higher amplifier output requires significant current from the power supply.

Use appropriately sized DC wiring and secure connections.

10. Build a Modular 2.1 System

A useful architecture is:

Stereo Amplifier → Left + Right

plus

CA-3316A → Subwoofer

This allows independent selection and adjustment of the stereo and bass amplifiers.

11. Test Before Installing Permanently

Before closing the amplifier inside a cabinet, verify:

• Audio input

• Subwoofer output

• Volume control

• Frequency control

• Power-supply stability

• Heat-sink temperature

12. Don't Treat 100W as Guaranteed at 12V

Available amplifier output depends strongly on supply voltage and speaker impedance.

A 12V supply cannot provide the same maximum output capability as a suitable 24V supply.

Troubleshooting

No Bass Output

Check:

• DC supply

• Input audio signal

• Speaker connection

• Volume setting

• Frequency-control setting

• Subwoofer condition

Bass Output Is Very Low

Check:

• Supply voltage

• Supply current capability

• Source signal level

• Volume setting

• Frequency setting

• Speaker impedance

Bass Sounds Distorted

Possible causes include:

• Amplifier clipping

• Insufficient supply current

• Excessive volume

• Subwoofer over-excursion

• Unsuitable speaker

• Poor enclosure design

Loud Hum

Check:

• Audio ground

• Signal cable

• Power-supply quality

• Cable routing

Keep low-level audio wiring away from AC mains wiring.

Amplifier Gets Hot

Check:

• Speaker impedance

• Supply voltage

• Output level

• Ventilation

• Heat-sink airflow

Subwoofer Plays Too Much Mid-Bass

Reduce the frequency/cut-off control until the subwoofer integrates better with the main speakers.

Subwoofer Sounds Disconnected From Main Speakers

Experiment with:

• Frequency setting

• Subwoofer volume

• Subwoofer position

• Main-speaker placement

The correct crossover setting depends on the complete audio system.

Engineering Principle

A good subwoofer system depends on:

Source + Crossover + Amplifier + Power Supply + Subwoofer Driver + Enclosure + Placement

Amplifier wattage alone does not determine bass quality.

FAQ

1. What is the CA-3316A?

The CA-3316A is a dedicated mono Class-D subwoofer amplifier board based on the TPA3116D2 amplifier IC.

2. Which amplifier IC does it use?

TPA3116D2

3. What is the maximum output?

Published maximum output:

Up to 100W

under suitable operating conditions.

4. Is it stereo?

No.

It is a mono subwoofer amplifier.

5. Is it a 2.1-channel amplifier?

Not by itself.

The CA-3316A provides only the amplified subwoofer channel.

It can be combined with a separate stereo amplifier to build a modular 2.1-channel system.

6. What supply voltage does it require?

DC 12V–24V

7. Which power supply is recommended?

For higher-output operation:

24V / 5A

is recommended.

8. Can I use a 12V adapter?

Yes.

However, available maximum output will be considerably lower than with a suitable 24V supply.

9. Can I use a 19V laptop adapter?

A suitable regulated 19V DC adapter can be used if:

• Polarity is correct

• Current capability is adequate

• Connector/wiring is compatible

10. Can I use a 24V SMPS?

Yes.

A suitable regulated 24V / 5A SMPS is a good choice for higher-output operation.

11. Can I use the RoboGears 36V 10A SMPS?

No.

36V exceeds the CA-3316A's published maximum supply voltage of 24V and may damage the amplifier.

12. Which speaker impedance is supported?

Published compatibility:

2Ω–8Ω

13. Can I use a 4Ω subwoofer?

Yes.

4Ω is within the supported range.

14. Can I use an 8Ω subwoofer?

Yes.

8Ω is supported, although obtainable maximum output will depend on the supply and load.

15. Can I use a 2Ω subwoofer?

The current RoboGears specification lists support down to 2Ω.

For demanding low-impedance operation, ensure good cooling and an appropriately capable power supply.

16. What does the volume knob do?

It adjusts the overall subwoofer output level.

17. What does the frequency knob do?

It adjusts the low-pass frequency/cut-off used for the subwoofer.

18. What is the frequency adjustment range?

Approximately:

20Hz–180Hz

19. Does it have a built-in low-pass filter?

Yes.

The board provides adjustable low-frequency filtering for its subwoofer application.

20. Does it have Bluetooth?

No built-in Bluetooth is specified.

A separate Bluetooth receiver can be connected to the audio input.

21. Does it have USB playback?

No built-in USB music playback is specified.

22. Can I connect it directly to a passive subwoofer?

Yes.

The amplifier is specifically designed to drive a compatible passive subwoofer.

23. Can I connect normal left and right speakers?

This board is intended for a single mono subwoofer, not normal stereo left/right speaker amplification.

Use a stereo amplifier for the main speakers.

24. Can I build a 2.1 system with it?

Yes.

Use:

Stereo Amplifier → Left + Right Speakers

and:

CA-3316A → Subwoofer

25. What is the efficiency?

Published efficiency:

>90%

26. What is the SNR?

Published signal-to-noise ratio:

100dB

27. What are the dimensions?

Approximately:

83 × 55 × 29mm

28. Does it have a heat sink?

Yes.

An integrated heat sink is provided.

29. What is included?

The current RoboGears package includes:

• 1 × CA-3316A Amplifier Board

• 2 × Potentiometer Knobs

30. Is the power supply included?

No.

A suitable DC power supply must be purchased separately.

31. Is the subwoofer included?

No.

A compatible passive subwoofer is required separately.

32. Does 100W mean it always outputs 100W?

No.

Actual output depends on:

• Supply voltage

• Supply current

• Speaker impedance

• Input signal

• Thermal conditions

• Wiring

The 100W figure represents the board's published maximum output capability under suitable conditions.

Important Safety Note

• Use DC power only.

• Observe correct polarity.

• Do not exceed 24V DC.

• Use a compatible 2Ω–8Ω subwoofer.

• Prevent speaker-output short circuits.

• Disconnect power before changing wiring.

• Maintain ventilation around the heat sink.

• Start testing at low volume.

Disclaimer

The 100W specification represents the published maximum output capability and should not be interpreted as guaranteed continuous output under every supply voltage and speaker-load condition.

Actual output depends on supply voltage/current, speaker impedance, audio signal, cooling and wiring.

PCB colour, heat-sink design, potentiometers, capacitors and minor component placement may vary between manufacturing batches while maintaining the intended CA-3316A functionality.