• Country
• United States of America (USA)

• Manufacturer / Brand
• Hewlett-Packard, (HP); Palo Alto, CA

• Year
• 1957 ?

• Category
• Service- or Lab Equipment

• Radiomuseum.org ID
• 129840

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

• Number of Tubes
• 8

• Valves / Tubes
• 6CB6 6CB6 6CB6 6CB6 6CB6 6AX5 12B4A 6U8 5651

• Wave bands
• - without

• Power type and voltage
• Alternating Current supply (AC) / 115; 230 Volt

• Loudspeaker
• - - No sound reproduction output.

• Material
• Metal case

• from Radiomuseum.org
• Model: Vacuum Tube Voltmeter 400 HR - Hewlett-Packard, HP; Palo Alto

• Shape
• Rack

• Dimensions (WHD)
• 19 x 7 x 10.8 inch / 483 x 178 x 274 mm

• Notes
• Model 400H has a 5" indicating meter with mirror scale and measures voltages from 0.1 mv to 300 volts. The high input resistance of 10 megohms effectively minimizes loading to circuits under test. A highly stabilized amplifier with 56 db feedback provides exceptional long term stability; even line voltage changes of *lo% cause negligible variations. Readings are direct in volts or db. Operation is extremely simple; input voltages up to 600 volts peak will not damage the instrument. The instrument is of highest quality construction throughout, and is available either in the lightweight, rugged -hp- portable cabinet or for rack mounting.

• Net weight (2.2 lb = 1 kg)
• 9.5 kg / 20 lb 14.8 oz (20.925 lb)

• Source of data
• - - Data from my own collection

• Mentioned in
• -- Original-techn. papers.

• Literature/Schematics (1)
• HP Katalog 1969

• Author
• Model page created by Sven Hoffmann. See "Data change" for further contributors.

• Other Models

• Here you find 393 models, 361 with images and 138 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Hewlett-Packard, (HP); Palo Alto, CA