• Country
• United States of America (USA)

• Manufacturer / Brand
• General Radio Company; Cambridge (MA)

• Year
• 1936–1938

• Category
• Service- or Lab Equipment

• Radiomuseum.org ID
• 301355

• • alternative name: GenRad

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

• Number of Tubes
• 3

• Valves / Tubes
• 955 75 1-V

• 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 [75] - 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 J" from September 1936. On page 54 it is called 726-A Thermionic Voltmeter but on later pages Type 726-A Vacuum-Tube Voltmeter (page 82). We find the description on pages 116 and 117. There is given the tube 75-type. The next catalog (K) is from 1939 and there the instrument carries the tube 6Q7G. See the modelpage here.

  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 J from September 1936 - for tube type 75, on page 116.)

• Author
• Model page created by Ernst Erb. See "Data change" for further contributors.

• Other Models

• Here you find 241 models, 212 with images and 131 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from General Radio Company; Cambridge (MA)