What is it

This is a USB-PD-emabled power adapter that is recommended to be used with the Louder and Amped series of ESP32 and Raspberry Pi-based devices. Originally, this power adapter comes from ASUS/HP/Lenovo laptops, but after testing and comparing different models, I stopped at this one as it produces no hearable noise or hissing, good power figures, and stable work with D-class amps

Features

• Color: Black
• Compatible Boards: see below
• Input: 100-240V /50-60Hz
• Output: 20V 3.25A, 15V 3A, 12V 3A, 9V 2A, 5V 2A
• Adapter Power: 65W
• Plug Tip Size: USB-C
• Certified: FCC, CE, UKCA

Compatibility list

ESP32 Boards

• Louder-ESP32-Pro and Louder ESP32 Mini (PD-enabled model)
• Louder Esparagus (USB-PD and DUAL models)
• Amped Esparagus (coming soon)

Adapter Capability

• Input Power (adapter): 65 W

• Usable Audio Output Power (80% efficiency):

65 W × 0.8 ≈ 52 W total

This 52 W is the total continuous power available for all audio combined.

Key Formulas

• RMS Voltage:
  V_RMS = sqrt(P × R)

• Output Current:
  I = sqrt(P / R)

Where: - P = power per speaker (W)
- R = speaker impedance (Ω)

Single Speaker (PBTL mode)

If only one speaker is connected, it can use the full ~52 W:

⚠️ Note: At 8 Ω, required voltage exceeds the 19 V supply, so actual power will be limited below 52 W.

Two Speakers (Stereo Configuration)

With two speakers, power splits across channels: - ~26 W per channel

Practical Observations

• The 20 V supply voltage becomes the limiting factor at higher impedances (especially 8 Ω).
• Lower impedance speakers (2–4 Ω) allow higher current draw and better utilization of available power.
• The adapter is well-matched for 2×20–30 W systems, depending on speaker impedance.
• Real-world output will vary depending on:
• amplifier design (BTL, Class-D behavior)
• thermal limits
• power supply sag under load

Final Notes

• Avoid significantly exceeding the voltage requirements of your speakers. For smaller speakers, use DAC/AMP gain settings to reduce the voltage swing over the speakers.
• This 20 V / 65 W adapter is a strong match for mid-power stereo systems, but not intended for high-power (>50 W per channel) setups.
• Always leave headroom (~10–20%) to prevent clipping and distortion.