KT66 GEC / Genalex Smoked Glass – Matched Pair – Amplitrex Tested – Made in GT. BRITAIN

KT66 GEC / Genalex Smoked Glass – Matched Pair – Amplitrex Tested – Made in GT. BRITAIN

Description:

This matched pair of KT66 GEC / Genalex , Made in Great Britain , belongs to the historic British production of the absolute reference for power valves. The famous Smoked Glass construction identifies one of the most iconic and sought-after versions, synonymous with superior construction quality, reliability and collectible prestige.

The tubes are selected as Matched Pair and tested on AMPLITREX , guaranteeing electrical coherence, operational stability and uniformity of sound output: a combination that immediately communicates Genalex excellence and authenticity.

Sound Characteristics

Bass: Deep, rounded, and perfectly controlled. The low end is authoritative yet elegant, with solid support that doesn't weigh down the musical message.

Mids: The true strength of the British KT66. Rich, fluid, and three-dimensional, with extremely natural vocals and a refined harmonic texture that conveys realism and presence.

Highs: Silky, airy, and well-extended. The highs are refined and never aggressive, with a typical Genalex sweetness that favors long, satisfying listening sessions.

Dynamics: Balanced and authoritative. Transient response is prompt but always controlled, with elegant microdynamics and composed macrodynamics.

Soundstage: Wide, deep, and perfectly layered. The soundstage is stable, three-dimensional, and very realistic, with natural instrument placement.

🎧 Use in Hi-Fi Amplifiers

Ideal for:

• single-ended and push-pull amplifiers designed for KT66,
• high-end British-inspired electronics,
• hi-fi systems that seek musicality, naturalness and timbral refinement.

Particularly suitable for jazz, classical, vocal and high-resolution listening.

🎸 Use in Music Applications

Also legendary in:

• British school guitar amplifiers,
• vintage circuits and boutiques,
• contexts where headroom, balance, and a rich, controlled harmonic response are required.

🎯 Note for audiophiles and technicians

These KT66 GEC / Genalex Smoked Glass – Matched Pair represent:

• the maximum expression of the British KT66 ,
• original production Made in Great Britain ,
• careful selection and testing on AMPLITREX ,
• first-rate sound, historical and collectible value.

A pair intended for reference systems and demanding collectors , for those who want the authentic Genalex sound , with all the elegance, musicality and authority that have made these KT66s a timeless legend.

Test Results:

Tested on AMPLITREX AT-1000 Tube tester:
Test Conditions: Va = 350; Vg2 = 250; Vg = -18V
Measurements are taken after approximately 10 minutes of preheating the tubes.
Average 100%: Gm = 5.2 ; Ia = 54 mA
TEST RESULT: VERY STRONG

Valve #1: Gm = 5.20 ; Ia = 58.2 mA
Valve #2: Gm = 5.30 ; Ia = 58.2 mA

Additional Tests Performed:

• Microphonics: Standard. Tested and approved for use in hi-fi and guitar amplifiers.
• Output Quality: Excellent – ​​Very strong and stable output, no fluctuations.
• Short circuits and GAS: Absent.

Conditions:

• Condition: Vintage tubes - tested with emission results consistent with NOS condition; pins in perfect condition. Supplied in our custom box for optimal protection.
  
• Functionality: Fully functional.
  
• Cosmetic condition: Good – Some lettering is eroded. Valve body in good condition. See photos for details.
  
• Manufacturing Code: Same manufacturing code, unreadable, MO Valve Co. Ltd. production, identifiable by construction features. 1950s

Find out why our valves are different →