High voltage regulated supply

Power supply design plays a crucial role in the performance of a tube amplifier. Most guitar amps rely on traditional unregulated power supplies, which can introduce noise and limit dynamic range.

However, the Single 25 features a high-voltage regulated power supply, a technology typically found in high-end Hi-Fi gear. This innovation brings significant benefits, including higher headroom, tighter bass, and ultra-low noise, setting the Single 25 apart from conventional designs.

The Challenge with Single-Ended

Single-Ended amplifier designs, such as the one used in the Single 25, are particularly sensitive to power supply noise because they lack the common-mode noise rejection of push-pull circuits. In traditional designs, large inductors (chokes) are used in combination with capacitors to filter power supply ripple, but this approach has limitations in both effectiveness and size. Even with careful filtering, residual hum can still affect the amp’s overall noise floor, and since chokes have parasitic series resistance, they cause voltage drop and power loss.

The Solution: A High-Voltage Regulated Power Supply

The Single 25 overcomes these limitations with its proprietary high-voltage regulated power supply. Instead of relying on large passive components, this regulated design actively stabilizes the voltage, effectively eliminating hum and ripple at the source. This innovation offers several key benefits:

  • Tighter bass response – With a rock-solid power supply, the amp delivers punchier and more defined low frequencies, preventing unwanted muddiness.

  • Higher headroom – By maintaining consistent voltage, the amp avoids early compression, preserving clarity even at high output levels.

  • Ultra-low noise – The advanced regulation system significantly reduces power supply noise, making the Single 25 ideal for studio recording and high-fidelity performance.

Performance Comparison

The graph below illustrates the effectiveness of the high-voltage regulated power supply in the Single 25 by comparing the noise spectrum of the same high-voltage source, first filtered by a traditional choke and then by the high-voltage regulator (both using a 47µF capacitor).

The first curve shows the raw power supply voltage immediately after the bridge rectifier, where significant ripple is present—measuring 3Vrms at 100Hz.

The second curve represents a traditional 4H choke-based filter, commonly used in guitar amplifiers, which reduces ripple to 60mVrms at 100Hz.

Finally, the third curve demonstrates the exceptional performance of the Single 25’s high-voltage regulator, reducing ripple to just 120µVrms at 100Hz—500 times lower than the classic inductor design.

This drastic improvement minimizes unwanted hum and interference, ensuring a cleaner signal path, improved dynamics, and a more responsive playing experience. Unlike traditional filtering, which relies on large inductors, this regulated design achieves superior ripple rejection while maintaining excellent voltage stability, contributing to the amp’s pristine tone and clarity.

Conclusion

By integrating a high-voltage regulated power supply, the Single 25 brings Hi-Fi-grade engineering into the world of guitar amplification.

This unique approach ensures a clearer, tighter, and more dynamic sound than traditional designs, while also eliminating unwanted hum and noise. Whether on stage or in the studio, guitarists can experience unparalleled tonal clarity, powerful dynamics, and a noise-free performance, making the Single 25 a true innovation in boutique amplifiers.