Unlock New Layers of Sound

The SELECT KT88 is the best KT88 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 KT88 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 KT88 is a beam tetrode introduced in 1956 as a variant of its smaller cousin, the KT66. Its name is derived from kinkless tetrode, an earlier name for the beam tetrode, and it’s been popular in high-fidelity stereo systems since its introduction. Since New Old Stock of the KT88 is especially rare, Ray Tubes is proud to offer brand-new KT88 vacuum tubes.

Sound Characteristics

The SELECT KT88 provides excellent low-frequency performance and high-resolution sound quality, suitable for users who are interested in strong low-frequency dynamic performance, especially for complex arrangements.

1. Bass Performance
   Solid and powerful, with deep bass and excellent control. Suitable for powerfully dynamic music such as rock and symphony orchestras.
2. Midrange Performance
   Full and delicate with a warm, multilayered tone. Vocals and strings in particular sound very natural, with rich details and strong layering of notes.
3. Treble Performance
   Clear with a very high resolution. Details are rich but not harsh, well-balanced, with a pure and bright sound quality.
4. Dynamics and Soundstage
   The dynamic range is very wide, accurately representing the contrast between loud and quiet elements. The soundstage is wide and deep, with very accurate positioning for an excellent sense of space.

Technical Specifications

Technical Specifications

• Tube Type: KT88
• Tube Socket: 8-pin
• Max Anode Dissipation Power: 42 W
• Max Screen Dissipation Power: 8 W
• Max Anode + Screen Dissipation Power: 46 W
• Max Anode Voltage: 800 V
• Max Screen Voltage: 600 V
• Max Grid Voltage: ~200 V
• Max Cathode Current: 230 mA
• Heater Voltage: 6.3 V
• Heater Current: 1.6 A
• Transconductance: 12 mA/V
• Amplification Factor: 8
• Total Height: 119 mm

Tetrode Connection

• Screen Voltage: 250 V
• Anode Voltage: 250 V
• Anode Current: 140 mA
• Grid Voltage: 15 V
• Grid Current: 3 mA
• Internal Resistance: 12 kΩ
• Amplification Factor: 8

Triode Connection

• Anode Voltage: 250 V
• Anode Current: 143 mA
• Grid Voltage: 15 V
• Internal Resistance: 670 Ω
• Amplification Factor: 8

Package Contents

• Set of four, two, or single vacuum tube
• User handbook featuring burn-in guidelines
• Certificate of authenticity and warranty

Compatible Amps

Explore Ray Tubes' Tube Amp Compatibility List.

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.