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iBasso PB5 Portable Balanced Vacuum Tube Headphone Amplifier



Product SKU: PB5


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Product Details

↓ Details provided by iBasso
(Specifications and appearance of this product are subject to change without notice)

Dual Nutube 6P1 Vacuum Tubes

Manufactured by KORG and Noritake, the 6th Gen Nutube operates exactly as a conventional triode vacuum tube and creates the same characteristic rich overtones that are sought after in triode tubes.  At the same time, Nutube achieves substantial power savings, miniaturization, and quality improvements when compared with many conventional vacuum tubes. 

Voltage amplification is achieved with the Nutube, which results in a captivating and distinctive vacuum tube sound, all while maintaining exceptional linearity.  

iBasso PB5 Osprey Overview

Unprecedented Six Batteries Form an Efficient Pure Power Supply 

The PB5 utilizes 6 batteries to establish a robust power supply system. The Nutubes are powered by two batteries while the other 4 batteries function as the power supply for the secondary amplifier.  With our efficient and pure power supply, you will experience very immersive and crystal-clear sound.

iBasso PB5 Osprey Internals

24 Position, 4 Section Stepped Attenuator

Extremely diminutive 24 position, 4 section stepped attenuator.

Optimal analog volume control enhances the ability to showcase the distinct analog characteristics of our vacuum tube amplifier.

Channel imbalance is within a range of less than +/-0.1dB.

When adjusting the volume, the noise floor is simultaneously attenuated.

iBasso PB5 Osprey Tubes

Excellent Power Delivery, 1700mW+1700mW@32ohm Driving Power

With the 6-battery power supply and transistor current amplifier, the PB5 delivers up to 1700mW+1700mW@32ohm.

Two-step Suspension & Cathode Input To Minimize Microphonics & Interference 

The two-step suspension absorbs vibration mechanically and minimizes the microphonic effect. The cathode input reduces the impedance, resulting in reduced signal interference from external sources.

Cutting Edge Parts To Present The Ultimate Analog Sound

- 24 position 4 section stepped attenuator with a channel tolerance of less than +/-0.1dB.

- Texas Instruments classic OPAMP OPA827, known for its exceptional performance and rich analog characteristics.

- Low VCEsat (BISS) dual transistors with a high output current of up to 2 amps.

- iBasso custom film capacitors contribute to the natural analog magic.

A Tube AMP For The MAX Users

The PB5 can use a line input voltage of up to 2.5 volts.

If higher than this, the sound will have distortion.

If you are using the DX220MAX, DX300MAX, or DX320MAX's line

out with the PB5, please do not use the highest gain setting.

MAX Series Line Out Voltage




High Gain    4.4V

High Gain    4.4V

Gain 44.5V

Mid Gain   1.8V

Mid Gain  1.8V

Gain 3  2.1V

Low Gain  1.2V

Low Gain  1.2V

Gain 2  1.4V

Gain 1  0.75V



  • Output Voltage:9Vrms (4.4mm balanced output), 4.5Vmrs (3.5mm single-ended output)
  • Output Power:1700mW+1700mW@32Ω
  • Line-in Voltage:<2.5V
  • Output Impedance: 0.25Ω (4.4mm balanced output), 0Ω (3.5mm single-ended output)
  • Frequency Response:20Hz-40kHz +0.5dB/-2dB
  • Recommended Headphone Impedance: 8~600Ω
  • Input Port:4.4mm TRRRS Balanced
  • Output Port:4.4mm TRRRS Balanced, 3.5mm TRRS Single-Ended
  • Gain: +11.5dB (High Gain), +2dB (Low Gain)
  • Charging Time:2.5 Hours
  • Average Play Time: 10.5 Hours
  • Size:139*82*28mm
  • Weight:352g

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