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Tube Database (7,341 tube types · 1,270 archive entries)

Other (3,257 tube types), Pre (2,314 tube types), Power (1,030 tube types), Rectifier (740 tube types)
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Tube-number record

SB21

0 archive entries

BrandElectrons, Inc. of Delaware
ClassFull-wave Rectifier
BaseOctal

Construction

Primary TypeRectifier
Rectifier TypeArgon Gas Filled
EnvelopeGlass
Base MaterialUX Radio Base
Sections2

Filament / Heater

MaterialUnknown
Warm-up Time15s

Absolute Maximum Ratings

Plate Voltage500 V
Cathode Current1000 mA

Audio Performance

Key Features
  • Graphite Anodes
  • Argon Gas Filling
  • Full-wave Rectifier

Typical Operation

ModePlate VGm (µmhos)Rp (Ω)µPlate mA
Max ratings at low current175 V———400 mA
Max ratings at standard current145 V———1000 mA
Max ratings at high current55 V———

Application Notes

It is preferable, but not essential, to light the filament before applying d-c. load. If omitted, each cold start at 1 ampere, 145 volts per plate consumes approximately one hour of tube life.

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    1250 mA