Ray Tubes SELECT 12AU7

The tubes that came in your preamp were chosen for price. The SELECT 12AU7 is chosen for sound: a new-production dual triode that Ray Tubes builds to its own audio specifications and keeps only when it ranks among the best of its batch.

The best 12AU7 you'll need, selected by listening.

The Design

SELECT takes the reliability and consistency of Ray Tubes' CORE line as its starting point and aims at one thing: more nuanced sound. Ray Tubes builds each tube with manufacturing partners to its own audio specifications, then sells only the best tubes from each batch; Ray Tubes says fewer than 5% of production meets its standard. Audio engineers with decades of experience take part in the selection from start to finish, including listening sessions in real-world conditions. The pins are gold-plated for corrosion resistance and improved conduction.

Every Ray Tubes tube passes a seven-step process in three phases. Phase one checks reliability: soldering inspection under a microscope and a 24-hour burn-in. Phase two measures critical parameters, matches tubes by current draw, and tests for microphonics. Phase three is an amplifier test with listening by Ray Tubes' sound engineers, plus targeted expert listening sessions on randomly chosen tubes. Measurements are recorded under each tube's serial number.

How It Sounds

Ray Tubes describes the SELECT 12AU7 as well balanced, with excellent resolution and dynamic sensitivity: clean, tight, controlled bass; clear mids with natural vocals and distinct layering; smooth, airy treble with rich detail; and fast transients inside a precise soundstage. Positive Feedback's Tom Gibbs gave it his highest recommendation and called it among the best of the best at its price, and Sound Perfection Reviews called it a safe, excellent buy for anyone wary of the variability of New Old Stock.

Where It Fits

The 12AU7 is a medium-gain dual triode, introduced in 1946 as the first noval (nine-pin) tube, and it works as a driver or phase inverter in the preamp stage of many tube amplifiers. Check your amplifier's manual for the tube type, then choose a single tube, a matched pair, or a matched quad to cover every socket. Ray Tubes publishes a compatibility list, and we can check your amp with you.

Warranty and Break-In

Ray Tubes' One Year Warranty covers manufacturing defects for twelve months, tied to the original invoice and the serial number on the box, so it transfers to a new owner. If one tube in a matched pair or quad fails, Ray Tubes replaces the whole set. Give new tubes 48 to 96 hours of use to break in; early quirks such as slight background noise or imbalance usually fade as hours accumulate. Each tube comes with a user handbook with burn-in guidelines and a certificate of authenticity and warranty.

Press Recognition

• Positive Feedback, Tom Gibbs (August 2024), reviewing the Ray Tubes 12AU7 SELECT. Gibbs gave it his highest recommendation. Read the review at Positive Feedback
• Sound Perfection Reviews (April 2024), reviewing the 12AU7. The reviewer called it a safe and excellent buy for anyone concerned about New Old Stock variability. Read the review at Sound Perfection Reviews
• ecoustics (September 2023), reviewing the 12AU7. The reviewer found a good option that adds some tube warmth while keeping detail and clarity. Read the review at ecoustics

Wondering whether the SELECT 12AU7 suits your amplifier, or how many tubes you need? Give us a call. We'll check your amp's tube complement with you.

Specifications

• Tube type: 12AU7 / ECC82 / 6189 / CV4003
• Socket: 9-pin
• Max anode dissipation: 2.75 W
• Max anode voltage: 300 V
• Max grid voltage: about 50 V
• Heater: 6.3 V, 0.3 A
• Transconductance: 2.2 mA/V
• Amplification factor: 17
• Internal resistance: 7.7 kΩ
• Pins: Gold-plated
• Availability: Single, matched pair, or matched quad
• Includes: User handbook with burn-in guidelines; certificate of authenticity and warranty
• Warranty: One year, transferable