•⁠  ⁠Product Overview – Airtight ATM4 Tube Amplifier, released in 1998, is a solidly engineered Class AB push-pull tube power amplifier using EL34 output valves, renowned for musical coherence, tonal purity, and long-term reliability.

•⁠  ⁠Circuit Topology – Hand-wired point-to-point construction with high-quality output transformers and conservative operating parameters ensures low distortion, excellent bandwidth, and stable performance across a wide range of loudspeaker loads.

•⁠  ⁠Sonic Performance – Airtight ATM4 Tube Amplifier delivers a harmonically rich midrange, controlled bass authority, and smooth extended treble, excelling in realism, spatial depth, and long, fatigue-free listening sessions.

•⁠  ⁠Specifications – Stereo power output approximately 36 watts per channel into 8 ohms, EL34 output tubes, 4/8 ohm taps, wide bandwidth response, and high-quality valve rectification supporting dynamic musical transients.

•⁠  ⁠Dimensions – Approx. 360 mm (W) × 220 mm (H) × 310 mm (D), featuring a compact yet robust chassis layout optimized for heat dissipation and mechanical stability.

•⁠  ⁠Weight – Approximately 21 kg, reflecting heavy-duty transformers, thick chassis materials, and conservative mechanical design essential for stable tube operation and long-term sonic consistency.