12AX7 / ECC83 NOS Amperex Bugle Boy Matched Pair AMPLITREX Tested Long Plates Foil Getter '59

12AX7 / ECC83 NOS Amperex Bugle Boy – Matched Pair – Long Plates – Foil Getter – Made in Holland ’59 – Amplitrex Tested

Description:

This pair of NOS Amperex Bugle Boy 12AX7 / ECC83, manufactured in Heerlen (Holland) in 1959, belongs to the historical phase of the first Long Plates Foil Getter, one of the configurations most sought after by enthusiasts today for its musicality, tonal refinement, and extremely meticulous internal construction.

The Heerlen manufacturing codes are authentic and perfectly consistent:

• Δ9B → 1959
• factory identified by the symbol Δ (Heerlen, Holland)

A pair from consecutive years of the Heerlen “golden era,” with a long plate foil getter internal structure typical of early European production.

The item is in authentic NOS condition, tested in our laboratory with Amplitrex AT-1000, with a VERY STRONG result, stable sections and perfectly suitable even for sensitive circuit positions.

Sonic Characteristics

The Heerlen '59 Long Plates are renowned for their three-dimensional, airy, and nuanced musicality. They offer a fuller and more natural presentation compared to the short plates of the 1960s.

• Bass: Deep, smooth, and articulate. The low end has body and definition without ever sounding boomy. Excellent control even in the most complex passages.
• Mids: The heart of Amperex's philosophy: bright, transparent, and harmonically rich mids, with vocal reproduction that remains among the most natural ever. Acoustic instruments and jazz emerge with remarkable realism.
• Highs: Silky, open, never aggressive. The foil getter architecture provides fine, brilliant highs rich in air, with superior micro-detail.
• Dynamics: Responsive and fluid. Fast yet natural attack, smooth release: the pair maintains a very musical and consistent performance with the test results.
• Soundstage: Wide, deep, three-dimensional. Splendid separation of musical lines, stable soundstage with excellent breath. Heerlen long plates are known precisely for this superior scenic capability.

🎧 Use in Hi-Fi Stereo Amplifiers
Perfect for:

• high-end preamplifiers,
• refined line stages,
• vintage European and American amplifiers,
• DACs with quality tube stages.

Ideal tubes for jazz, vocal, ambient, classical, and acoustic music, where a natural, rich, and three-dimensional presentation is desired.

🎸 Use in Musical Amplifiers
Excellent for vintage and boutique guitar amps:

• sweet and musical break-up,
• rich harmonics,
• bright European clean,
• warm and controlled crunch.

Suitable for positions where vintage harmonics and tone are sought.

🎯 Note for audiophiles and technicians
This pair represents a rare and highly sought-after combination.

Perfect for collectors, restorers, and enthusiasts who desire the true sonic signature of 1950s Heerlen Amperex tubes.

Test Results:

Tube tested on AMPLITREX AT-1000 Tube Tester:

• Test Conditions: Va = 250V ; Vg = -2V
• Average 100%: Gm = 1600 ; Ia = 1.2 mA
• Test Result: VERY STRONG

Tube 1:

• Section 1: Gm = 1600 ; Ia = 1.0 mA
• Section 2: Gm = 1500 ; Ia = 0.9 mA

Tube 2:

• Section 1: Gm = 1400 ; Ia = 1.0 mA
• Section 2: Gm = 1400 ; Ia = 0.8 mA

• Microphonics: Very Low. Tested and suitable for use in hi-fi and guitar amplifiers. Suitable for use in V1.
• Emission Quality: Excellent – Very strong and stable emission, no fluctuations.
• Shorts and GAS: Absent.

Condition:

• Condition: Vintage Tubes - Tested and perfectly working. Supplied in our custom box for optimal protection.
  
• Functionality: Perfectly operational.
  
• Aesthetic Condition: Good – Labels partially eroded, but still legible. Tube body in good condition. See photos for details.
  

Manufacturing Code:

• ???  Δ9B - ??? → Internal structure consistent with Heerlen Long Plate Foil Getter production from the late 1950s. - Δ9B Δ → Heerlen (Holland), 9 (on three digits) → 1959 - B → February 

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