Vacuum-Tube Voltmeter (Thermionic) 726-A 6Q7G

General Radio Company; Cambridge (MA)

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  • Year
  • 1939
  • Category
  • Service- or Lab Equipment
  • Radiomuseum.org ID
  • 279496
    • alternative name: GenRad

Click on the schematic thumbnail to request the schematic as a free document.

 Technical Specifications

  • Number of Tubes
  • 3
  • Wave bands
  • - without
  • Power type and voltage
  • Alternating Current supply (AC) / Less than 30 W, either 42, 50, 60 Hz, 100-130V or 50 Hz, 200 to 260 Volt
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Wooden case
  • from Radiomuseum.org
  • Model: Vacuum-Tube Voltmeter 726-A [6Q7G] - General Radio Company;
  • Shape
  • Tablemodel, slant panel.
  • Dimensions (WHD)
  • 9.5 x 14 x 8.5 inch / 241 x 356 x 216 mm
  • Notes

  • This instrument is listed with picture in the General Radio Co, "Catalog K" from 1939. Here you find the older version from 1936 with the tube type 75 instead of 6Q7G.

    Range 1.5 / 5 / 15 / 50 / 150 V AC, 20 Hz - 50 MHz; with a probe containing the 955 tube. Catalog 1939 mentions less than 1 % between 20 cycles and 50 megacycles. With the probe tips removed, at 100 megacycles the voltage indicated is about 3 % larger than accross heh probe terminals.

    Important: Open the probe head only on the "Low" end: The two screws and the Plug "low" to get to the tube 955.

    There are at least two versions regarding the tube line up: Early models (at least up to Serial Nr. 251) use the tube 75 (From Tungsram) with the 6-Pin-Base, which arrived on the market 1933 - and later sets use the 6Q7G from 1936 with Octal base. Since General Radio Copmpany-Catalog H from April 1935 does not mention the type 726-A (or 726), it is clear that the first introduction via catalog was in 1936. 

     

  • Net weight (2.2 lb = 1 kg)
  • 17.5 lb (17 lb 8 oz) / 7.945 kg
  • Price in first year of sale
  • 165.00 $
  • Literature/Schematics (1)
  • -- Original-techn. papers.
  • Literature/Schematics (2)
  • - - Manufacturers Literature (Catalog K from 1939 - on page 116.)

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