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. By completely eliminating the output transformer in its OTL configuration, sound clarity, density, and sense of speed are dramatically enhanced. It reproduces a sound that combines the warm, supple texture of tube amplifiers with modern precision.
Each channel is equipped with two 6C41C tubes, and the unique driver stage ensures an output of 8W. The distortion rate at 0.5W is only 0.01%, and the adoption of active noise reduction technology keeps hum and noise at an extremely low level. This amplifier allows detailed nuances to emerge beautifully even at low volumes, offering high silence.

Optimized Futterman-type circuit for the modern era — achieving both transparency and control

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

Structural beauty and reliability through Nordic craftsmanship

The main circuits are arranged on high-quality PCBs, while critical points that directly affect sound quality are assembled point-to-point (PtP) by skilled technicians.
Unnecessary vibrations and micro-noises are thoroughly eliminated through ceramic solder supports that withstand up to 5kV and a 10mm-thick aluminum chassis.
All parts and assemblies are designed in Sweden with high durability and long-term stability.

Advanced motorcycle adjustment - design to keep the sound optimal at all times

Microprocessor-controlled motorcycles automatically adjust the optimum bias and offset during operation.
The calibration works just before the amplifier stop, and the next startup starts in an ideal state.
Vacuum tube replacement is also automatically optimized, and there is no annoyance of manual adjustment.

Dense and stretchy sound image - OTL power amplifier inheriting the power of PA12

PA3B is a model that combines the rich facial expressions of vacuum tube amplifiers with the transparency and instantaneous power unique to OTL systems in high dimensions.
Spacious sound field, beautiful middle and high range, pullcontrolled bass responseBut in harmony with nature, the essence of music is drawn as it is.

Overwhelming transparency and speed

• It is like an OTL amplifier, and the "direct feeling" that does not pass through the output transformer is overwhelming. There is really little turbidity of the signal, and the transparency of the middle and high range is outstanding. It stands up so that the sound goes out quickly, and the reaction is quick anyway. I could hear the detailed nuances well, and I felt the charm of "this OTL" in the balance of speed and clearness.

Rich musicality and beauty of harmonics

• Smalloutput tubeThe beautiful harmonic ingredients that are unique come out firmly, and the sound has a natural warmth and density. Although it is clear, there is no coolness, the transparency and the rich sound of the vacuum tube are exquisitely balanced. The "musical comfort" that you want to listen to for a long time is impressive, especially with vocals and acoustic songs.

Ultimate localization and phase characteristics

• Thanks to the excellent phase characteristics of the OTL structure, the focus of the sound image is really sharp. The position of the instrument and vocals is determined beautifully, and the depth and layers of the sound field can be understood as if taken into your hands. For those who value delicate stationary expressions, I felt it was a strong attraction.

Tight and agile low range

• Low range is not a type that gives a flashy sense of quantity, but it is a sound that is tight, agile and sharp. It is compatible with high-efficiency speakers, and the rhythm is very sharp. Each sound reacts quickly, and a good low range of teeth acts as the driving force of the music.