Ray Tubes SELECT 300B

A single-ended triode amplifier lives or dies by its 300B, because that one tube carries the whole output stage. The SELECT 300B is a new-production directly heated triode that Ray Tubes builds to its own audio specifications and keeps only when it ranks among the best of its batch.

The benchmark SET tube, chosen 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 says the SELECT 300B captures what makes the 300B legendary: lush mids, graceful highs, and a coherent, musical bass foundation. Bass is controlled, supple, and elastic, with moderate extension that suits acoustic, jazz, and classical music. The midrange is where Ray Tubes says it excels, with a rich, full-bodied tone and a touch of warmth that flatters voices from baritone to soprano, and the treble is smooth, layered, and non-fatiguing.

Where It Fits

The 300B was introduced in 1938 and powered the cinemas of Hollywood's Golden Age. Audiophiles have valued it for decades for its low noise and good reliability. Check your amplifier's manual for the tube type, then choose a single tube, a matched pair, or a matched quad for your output stage. Have your amplifier's bias checked whenever you change output tubes. If you want to go further, the RESERVE 300B is Ray Tubes' top version.

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

Ray Tubes' tubes have drawn reviews from Positive Feedback, Stereophile, and HiFi.nl, among them reviews of the RESERVE 300B. Reviews of the SELECT 300B by itself are on the way. Read HiFi.nl's review of Ray Tubes

Wondering whether the SELECT 300B 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: 300B
• Socket: 4-pin
• Output power: 6.6 W
• Filament: 5 V, 1.2 A
• Max anode voltage: 480 V
• Max anode dissipation: 40 W
• Cathode current: 100 mA self-bias; 70 mA fixed bias
• Input capacitance: 9 pF
• Output capacitance: 4.3 pF
• Transfer capacitance: 15 pF
• Static conditions: 300 V anode, -60 V grid, 60 mA anode current
• Transconductance: 5.5 mA/V
• Internal resistance: 0.7 kΩ
• Amplification factor: 3.85
• 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