The world best C3gS you can get:
1. Factory new out from the box
2. Measured and matched according the Telefunken specifications

FYI. These tubes were measured in autobias mode according to the manufacturer's specifications.
More information at the end of this description.


Siemens C3gS — MATCHED PAIR
CONDITION & IDENTIFICATION
Condition NOS / NIB – New and unused
Original print Perfect, fully preserved
Original boxes Clean, very good condition
Serial number 351033 + 351034 
TEST RESULTS & MATCHING
RoeTest V11 Autobias mode
Parameter Tube 1 Tube 2 Datasheet (100%)
Ia – Anode Current 13,5 mA 13,6mA 13,00 mA
Gm – Transconductance 15300 µmhos 15600 µmhos 14000 µmhos
Manufacturer Tolerance (Datasheet)    Ia: 10,00–16,00 mA   |   Gm: 12000–16300 µmho

S means:
  • Special selection
  • small tolerances
  • low Microfonics
  • stable values

    • Test equipment: RoeTest V11
    Test and selection in Auto-Bias mode according to the manufacturer’s specifications.

    Preamp tubes operate in the amplifier with automatic grid bias. Therefore, the tubes are also tested and selected under these conditions.

    Testing with a fixed grid bias does not correspond to the actual operating conditions of a preamp tube and may therefore lead to misleading results.

    Auto-Bias testing provides a practical and reliable method for evaluating and selecting tubes.