RT-SL-300B-X4
- RT-SL-300B-X4
- RAY TUBES
Ray Tubes 300B SELECT Series Triode Vacuum Tube Matched Quad.
Unlock New Layers of Sound
The SELECT 300B is the best 300B vacuum tube you’ll ever need. It goes above and beyond the baseline with more involved production and stricter selection, all in pursuit of superior sound. The SELECT Collection brings out the best in all your favorites.
Hand selected and tested, the Ray Tubes SELECT 300B features gold pins for corrosion resistance and improved conduction. The SELECT Collection is a substantial upgrade from both New Old Stock and other new production tubes. Fewer than 5% of production meets our standards.
The 300B is a legendary tube. Introduced in 1938, it powered the cinemas of Hollywood’s Golden Age. Audiophiles have treasured it for decades for its low noise and good reliability. Ray Tubes is proud to introduce our take on a classic.
Sound Characteristics
The SELECT 300B captures the heart of what makes the 300B tube legendary—lush mids, graceful highs, and a coherent, musical bass foundation. It stands out for its ability to deliver genuine tube character with a high degree of listenability and system compatibility, making it a compelling choice for music lovers seeking both value and performance.
- Bass Performance
Controlled and cohesive. Bass notes are supple and elastic, with moderate extension and just the right amount of body. It doesn’t overwhelm the soundstage, making it ideal for genres like acoustic, jazz, and classical music. - Midrange Performance
The midrange is where the SELECT 300B truly excels. Rich, full-bodied tonal character with a touch of warmth. Vocals are especially well rendered, from baritone to soprano.
Treble PerformanceDelivers the characteristic smoothness of the 300B, with a layered treble extension and a natural sense of sparkle. A soft warmth in the upper register gives strings and female vocals a refined, non-fatiguing presence.
Technical Specifications
- Tube Type: 300B
- Tube Socket: 4-pin
Filament (Heater) Ratings
- Filament Voltage: 5 V
- Filament Current: 1.2 A
Maximum Ratings
- Plate (Anode) Voltage: 480 V
- Plate Dissipation: 40 W
Typical Operating Conditions
- Plate Current (Self-Bias): 100mA
- Plate Current (Fixed Bias): 70mA
Interelectrode Capacitance at Zero Bias
- Input Capacitance: 9 pF
- Output Capacitance: 4.3 pF
- Transfer Capacitance: 15 pF
Static Characteristics (under typical conditions)
- Plate Current (Ia): 60 mA
- Transconductance (Gm): 5.5 mA/V
- Plate Resistance (Rp): 0.7 kΩ
- Amplification Factor (μ): 3.85
- Output Power (Pout): 6.6 W
Package Contents
- Set of Four vacuum tube
- User handbook featuring burn-in guidelines
- Certificate of authenticity and warranty
The Ray Tubes One Year Warranty
Most vacuum tubes are notoriously fickle. That’s why warranties are rare. But we trust our products and we’re proud to offer our One Year Warranty against manufacturing defects. For more details, check out our warranty page.