Heathkit V-7A Vacuum Tube Voltmeter VTVM AC DC Ohms 1.5-1500V w/ HV Probe Leads

Heathkit V-7A Vacuum Tube Voltmeter VTVM AC DC Ohms 1.5-1500V w/ HV Probe Leads

The Heathkit V-7A is a classic vacuum tube voltmeter (VTVM) built from one of Heath Company's most popular kit designs. A VTVM uses the high input impedance of a vacuum tube amplifier stage — typically 11 megohms or more — to measure voltage without loading the circuit under test, making it far more accurate than a simple passive VOM for work on high-impedance circuits such as radio and amplifier stages. The V-7A measures AC voltage, DC voltage (positive and negative), and resistance (ohms) via a large, easy-to-read analog meter movement with multiple calibrated scales.

Specifications & What's Included

• Model: Heathkit V-7A
• Type: Vacuum Tube Voltmeter (VTVM)
• Measurement functions: AC voltage, DC+ voltage, DC− voltage, Resistance (Ohms)
• Voltage ranges: 1.5V, 5V, 15V, 50V, 150V, 500V, 1500V
• Resistance ranges: RX1, RX10, RX100, RX1000, RX10K, RX100K, RX1 MEG
• Front panel controls: Function selector knob (AC/DC+/DC−/Ohms/AC Off), Range selector knob, Zero Adj. trimmer, Ohms Adj. trimmer
• Display: Large multi-scale analog meter movement
• Input impedance: High-impedance tube input stage (characteristic of VTVM design)
• Form factor: Portable benchtop with metal carry handle
• Includes: High-voltage probe (aluminum barrel, red tip, needle point, braided cable with alligator clip ground lead)
• Includes: Red and black test leads with banana plugs and alligator clips

Applications

The Heathkit V-7A dates from the late 1940s to mid-1950s — the era when vacuum tube electronics dominated consumer and professional equipment, and Heath Company kits were a central part of the hobbyist and technician market. VTVMs like the V-7A were the standard bench instrument for servicing vacuum tube radios, televisions, amplifiers, and test equipment, where their high input impedance was essential to avoid disturbing sensitive high-impedance circuits that a lower-impedance VOM would load down and misread. The V-7A was sold as a kit for home assembly and was widely built by radio amateurs, electronics students, and bench technicians throughout the 1950s. Today, the V-7A is sought by vintage radio and audio restorers who prefer period-correct instruments for servicing tube equipment, as well as by collectors of classic Heathkit and mid-century test gear. It is also occasionally used by vintage amplifier hobbyists who appreciate the VTVM's behavior on high-impedance nodes in tube circuit work.