Professional Tube Testing
This set was tested and certified by RoeTest V11 Professional Tube Testing System with the following result:
Tube 1:
Measured transconductance(GM): 1.46/1.69 mA/V - 91%/106% (100% = 1.6 mA/V)
Measured plate current(IA): 1.15/1.435 mA - 96%/120% (100% = 1.2 mA)
Tube 2:
Measured transconductance(GM): 1.81/1.68 mA/V - 113%/105% (100% = 1.6 mA/V)
Measured plate current(IA): 1.532/1.292 mA - 128%/108% (100% = 1.2 mA)
Curve trace is also included in the original RoeTest report.
Appearance & Cosmetic condition
Silkscreen: 98% - 100% (Immaculate)
Date codes:
641 R6C4 (R = Mitcham, GB, 6 = 1966, C = March, 4 = Week 4 of the production month)
641 R6D1 (R = Mitcham, GB, 6 = 1966, D = April, 1 = Week 1 of the production month)
Packaging
NEW reproduction Mullard tube boxes.
6057 "Shark Tooth" (1950s)
Mullard 6057 CV4004 Box Plates Matched Pair - Mitcham '57 - Same Code - Strong
$443.75
Professional Tube Testing
This set was tested and certified by RoeTest V11 Professional Tube Testing System with the following result:
Tube 1:
Measured transconductance(GM): 1.33/1.49 mA/V - 83%/93% (100% = 1.6 mA/V)
Measured plate current(IA): 1.12/1.127 mA - 90%/90% (100% = 1.25 mA)
Tube 2:
Measured transconductance(GM): 1.44/1.3 mA/V - 90%/81% (100% = 1.6 mA/V)
Measured plate current(IA): 1.075/0.797 mA - 86%/64% (100% = 1.25 mA)
Curve trace is also included in the original RoeTest report.
Appearance & Cosmetic condition
Silkscreen: 98% - 100% (Immaculate)
Date codes:
641 R7G (R = Mitcham, GB, 7 = 1957, G = July)
641 R7G (R = Mitcham, GB, 7 = 1957, G = July)
Packaging
NEW reproduction Mullard tube boxes.
