Overview

Design philosophy

To design a practical, dependable, easy-to-use integrated loudspeaker amplifier that is beautifully crafted, sonically stunning, and enjoyable to use. We achieve this through a simple circuit and execute it in a carefully planned implementation.

Class-A, fully balanced, all-tube with in-house custom output transformers, zero feedback, 25 watts per channel. A dual mono integrated amplifier configuration that is uniquely equipped with a dual motorized volume control, allowing independent volume adjustment for left and right channels to dial in the perfect soundstage. 

The chassis is a one-piece construction, machined from a massive billet aluminum block. The finish is sandblasted and anodized in sophisticated black and gold trims. There are 3 analog inputs (two XLR and one WBT RCA) that are selectable via the front of the right dial. The output is via one set of WBT Nextgen speaker binding posts. The amplifier output impedance can be easily switched between a standard configuration of 8 Ohm or 4 Ohm via the front left dial. Standard features include a soft-start and faulty-tube detection / protection. The amplifier includes a matching volume remote control that is made out of a solid piece of anodized aluminum, accentuated with gold-finished buttons.  

Single block of aluminum chassis construction

The benefits of using a single block of aluminum are not only for a visual presentation, but also for sonic performance. Inside the block, designated compartments are precisely carved out for audio components placement so that the audio signal is free from airborne frequency contamination. In addition, the massive block of metal acts as a giant heat sink, allowing the amplifier to operate in an optimal working temperature. Moreover, a single block construction maximizes structural integrity and thus reduces mechanical vibration and eliminates resonance.

The driver stage is in two gain stages

The drive stage is a crucial component when utilizing 300B power tubes. 300B is known to produce an organic sound that has a rich, warm tone, pleasant to listen to. To drive the 300B at optimal performance, the driver stage must produce a high voltage sufficient to drive the 300B. A typical drive stage would be involved with two active drive stages. From our experience, the simpler the drive stage, the better the sound and the lower the noise is expected. For this reason, we replaced an active driver with our in-house developed STEP-UP driver, which is deployed in the first drive stage.

* The first stage is input voltage gain through our STEP-UP Driver pioneered in our WA24 20th Anniversary headphone amp and flagship WA234 Mono-block amplifier. The STEP-UP Driver is a passive component that greatly reduces peripheral electric components and simplifies power supply requirements, delivering an ultra-low-noise, ultra-high bandwidth output. 

* The second stage is a pair of 6SN7 driver tubes utilized with a dual triode. Each 6SN7 is connected in a push-pull configuration, responsible for each channel. With the help of the 1st stage gain, the tube gain stage can operate in low-stress, which in turn achieves a high bandwidth and ultra-low-noise output.

Output stage

One matched quad of 300B is used. Each channel consists of one pair of 300B connected in push-pull configuration. The power transfer between the loudspeakers and the power tubes is coupled by our in-house developed custom output transformers (OPTs). The WA300-BAL OPTs are hand-wound and oversized. Our output transformer is a hallmark of Woo Audio's core technology, designed specifically for vacuum tube audio amplifiers. Our OPTs are low-loss, uncolored, high-bandwidth, and capable of driving heavy loads with grip and control. Naturally, the WA300-BAL can handle demanding speakers down to 86dB sensitivity rating with authority.

Woo Audio is known for offering a wide range of vacuum tube headphone amps. They earned a reputation for making tube amps that are low-noise floor, which are suitable for headphones. The new WA300-BAL power amp is no exception. It produces a nearly pitched dark background, leaving you to focus on the music.

Highlights

• Introduced in March 2026

• Latest flagship integrated power amplifier

• Standard package:

  This package includes a set of stock tubes that came with your demo amp. We will include either Psvane or Electro Harmonix tubes, depending on availability.

• Premium package:

  This package includes a set of premium tubes that consists of a matched quad of TA-300B and a pair of RCA 6SN7 NOS tubes.

• Designed and assembled in New York, USA

• Three-year limited warranty [learn more]

In the Box

• WA300-BAL Integrated Power Amplifier x 1

• 300B power tube x 4

• 6SN7 driver tube x 2

• Quick start guide

*AC power cord and audio cables are not included