Q-tron Audio PA34B 80W High-End OTL Mono Power Amplifier
Product code:Q-tron Audio PA34B 80W High-End OTL Mono Power Amplifier
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Overwhelming Driving Power and Transparency
A flagship OTL monoblock that fully brings out the potential of large speakers.
Q-tron PA34B – An 80W OTL power amplifier that easily handles high-impedance loads
The PA34B is a monoblock OTL power amplifier that expands greatly on the output and current supply capabilities of Q-tron’s flagship model, the PA12B. It features four 6C33C vacuum tubes in the output stage, providing about twice the current capacity of the PA12B, which allows it to exert excellent control over low-efficiency speakers and large floor-standing models. Despite being a tube amplifier, it delivers sufficient output—80W at 8Ω and 60W at 4Ω—making it suitable for modern speaker combinations.
By eliminating the output transformer through an OTL (Output Transformer Less) design, the PA34B removes any distortion or bandwidth limitations caused by transformer magnetic properties, allowing extremely fast attack and direct, highly transparent reproduction. A modernized Futterman circuit in a push-pull configuration is employed, keeping the output impedance between 0.2 and 1.5Ω, enabling stable driving even for low-impedance speakers.
Redesigned Futterman Circuit for Both Transparency and Control
The output stage of the PA34B uses a Q-tron-tuned Futterman OTL circuit. To maintain balanced push-pull operation without a transformer, 6N6P-I tubes are used for the amplification stage and 6N2n-EB for the first stage, achieving both linearity and wide bandwidth.
In the very low signal range around 2W, it operates extremely cleanly, maintaining distortion levels near the measurement limit. Even at practical output levels around 25W, distortion increases very little, allowing energy to rise smoothly without losing tonal transparency or density. This linearity is maintained without excessive negative feedback, thanks to the precision and stability of the circuit itself.
Active noise cancellation to enhance quietness and stability
The PA34B is meticulously designed to combat noise. By adopting a power supply design with active noise cancellation technology, hum and noise levels are managed at extremely low values of below -100 dBA. This ensures a clear background and a natural sense of air extending deep into the soundstage, earning the PA34B high praise for its reproduction of classical hall tones and ambience.
Quietness and stability created by a large PCB, PtP wiring, and a 10mm-thick aluminum chassis
The chassis is made from a 10mm-thick aluminum block, effectively blocking even subtle external vibrations. This sturdiness supports a solid low-end stability and the clear, delicate mid and high frequencies.
Drive capability comfortably handling complex speaker loads
Housed in a robust cabinet measuring 275 × 330 × 400 mm, weighing 19 kg per unit, it ensures stable placement. The PA34B accepts both RCA and XLR inputs, allowing for versatile system configurations.
Overwhelming driving force and OTL-specific clear soundstage expression
The soundstage comes to life quickly, with air density and depth clarity remaining unclouded, maximizing the speakers’ latent potential.
The full impact of high volume and the fading of the smallest reverberations are all rendered clearly, without any muddiness──
The PA34B is an OTL monoblock amplifier designed for listeners who want to deeply explore the essence of music.
| Output: | 80W (at 8Ω, THD < 1%), 60W (at 4Ω, THD < 1%) |
|---|---|
| THD at 1kHz: | <0.01% at 2W, at 25W< 0.1% |
| Frequency Response: | 5 ~ 100kHz / -1dB |
| Power Bandwidth: | 10 ~ 100kHz / -1dB |
| Rise Time: | 0.5μs |
| Hum and Noise: | < -100dBA |
| Output Impedance: | <0.2Ω ~ 1.5Ω |
| Input Terminals: | RCA phono + XLR |
| Dimensions: | 275 x 330 x 400 mm (W x H x D) |
| Weight: | 19kg / per unit |
