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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

7504S

0 archive entries

BrandMullard
ClassDecade Selector and Counting Tube
BaseCRT / special base

Construction

Primary TypeOther / special
EnvelopeGlass
Sections10 main cathodes

Filament / Heater

Absolute Maximum Ratings

Plate Voltage550 V
Grid 1 Voltage-20 V
Cathode Current0.525 mA

Audio Performance

Key Features
  • Short all-glass
  • Neon-type glow
  • Bidirectional counting
  • High mechanical tolerances

Typical Operation

ModePlate VGm (µmhos)Rp (Ω)µPlate mA
Recommended Double Pulse Drive475 V———0.34 mA

Application Notes

Unused cathodes should be connected together and returned to zero voltage. All voltages are referred to the most positive supply potential to which any main cathode is returned.

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