Q-tron Audio PA3B 2x8W Push-Pull Tube OTL Power Amplifier

The Q-tron PA3B is a high-end tube amplifier that achieves "over 10 times lower distortion" compared to other OTL (Output Transformer Less) amplifiers thanks to its unique driver circuit. The OTL configuration, which completely eliminates the output transformer, dramatically improves sound transparency, density, and speed. It reproduces sound that retains the warm, supple texture of tube amplifiers while also providing modern precision.
Each channel is equipped with two 6C41C tubes, and its unique driver stage ensures an 8W output. It achieves excellent characteristics, with a distortion rate of just 0.01% at 0.5W. By adopting active noise reduction technology, hum and unwanted noise are kept to extremely low levels. This is a highly quiet amplifier where even the smallest nuances are beautifully revealed at low volumes.

Optimized Futterman Circuit for Modern Use — Combining Transparency and Control

The PA3B uses a Futterman-type circuit optimized by Q-tron for modern components and analysis technology.
The Futterman configuration is a unique OTL design that drives speakers directly without an output transformer, known for its wide bandwidth and excellent linearity.
Q-tron has added its own balance adjustments and stabilization technology to this traditional configuration, achieving sound with unwavering driving power against speaker loads while maintaining high transparency.
It adopts the same chassis size as the PA12, inheriting the expansive soundstage and powerful expression of the PA12, while offering the soft and dense tonal quality unique to 6C41C tubes.

Nordic Craftsmanship for Structural Beauty and Reliability

The main circuits are mounted on high-quality PCBs, and critical areas directly affecting sound quality are assembled point-to-point (PtP) by skilled technicians.
Unnecessary vibrations and fine noise are thoroughly eliminated with ceramic solder supports that withstand up to 5kV and a 10mm thick aluminum chassis.
All components and assembly are done domestically in Sweden, designed for high durability and long-term stability.

Advanced Auto Bias Adjustment — designed to always maintain optimal sound

The microprocessor-controlled auto-bias function automatically adjusts the optimal bias and offset during operation.
Calibration kicks in just before the amplifier stops, ensuring an ideal state at the next startup.
Even when tubes are replaced, optimization is automatic, eliminating the hassle of manual adjustment.

Dense and expansive sound — OTL power amplifier inheriting the capabilities of the PA12

The PA3B is a model that combines the rich expression of tube amplifiers with the transparency and responsiveness unique to the OTL system at a high level.
A wide soundstage, beautiful mid-to-high range, and tight bass naturally harmonize, faithfully bringing out the essence of music.

Overwhelming Transparency and Sense of Speed

• True to OTL amplifier characteristics, it offers an overwhelming “direct feel” without passing through an output transformer. Signal muddiness is minimal, and the transparency of the mid-to-high range is outstanding. The sound rises clearly, with extremely fast responsiveness. Even subtle nuances can be heard clearly, and the balance of speed and clarity strongly conveys the classic appeal of an OTL.

Rich Musicality and Beautiful Harmonics

• Smalloutput tubeIt produces beautifully rich harmonic components unique to its design, giving the sound a natural warmth and density. It's clear without feeling cold, and the sound achieves a perfect balance of transparency and the rich resonance characteristic of vacuum tubes. The 'musical comfort' that makes you want to listen for hours is particularly impressive, and its appeal stands out especially in vocal and acoustic music.

Ultimate Imaging and Phase Characteristics

• Thanks to the excellent phase characteristics of its OTL structure, the sound image is truly sharp. The positioning of instruments and vocals is precise, and you can clearly sense the depth and layers of the soundstage. For those who value delicate spatial expression, this is a very attractive feature.

Tight and Agile Bass

• The bass does not emphasize excessive volume, but it is firm, agile, and crisp. It pairs well with high-efficiency speakers, making the rhythm extremely clear. Each note responds quickly, and the snappy bass drives the music forward.