Reference

Everything in this volume is drawn from primary documents: Heath’s own assembly manuals, scanned and hosted at the Internet Archive, and Heath’s catalogues and flyers, scanned at World Radio History. Where a figure appears in two sources with different values, both are given. The manual list at the end records the data needed for the hosting decision set out in the project’s rules — publication year, whether a copyright notice was seen, and whether a copyright-renewal search has been made.

6.1 Full specifications: the table-top models

Table 1 — Full specifications: the table-top models

	V-7 / V-7A	IM-11	IM-18	IM-5218
Years	1954–1961	1961–1969	1969–1977	1977–1983
DC ranges, full scale	1.5, 5, 15, 50, 150, 500, 1500 V	same	same	same
DC input resistance	11 MΩ (1 MΩ in probe)	same	same	same
DC sensitivity	7,333,333 Ω/V on 1.5 V	same	same	same
DC accuracy	±3% of full scale	same	same	same
AC ranges, RMS	1.5, 5, 15, 50, 150, 500, 1500 V	same	same	same
AC ranges, peak-to-peak	4, 14, 40, 140, 400, 1400, 4000 V	same	same	same
AC accuracy	±5% of full scale	same	same	same
Frequency response	±1 dB, 42 c/s – 7.2 Mc (5 V range, 600 Ω)	±1 dB, 25 c/s – 1 Mc	±1 dB, 25 Hz – 1 MHz	same
AC input impedance	≈1 MΩ shunted by 35 pF	1 MΩ, 35 pF	1 MΩ, 35 pF	1 MΩ, 35 pF
Ohms ranges	×1, ×10, ×100, ×1000, ×10K, ×100K, ×1 MEG (10 Ω centre)	same	same	same
Ohms span	0.1 Ω – 1000 MΩ	same	same	same
Meter	4½ in, 200 µA, polystyrene case	same	same	same
Multipliers	1% precision	same	same	same
Circuit board	1/16 in XXP (V-7); 3/32 in (V-7A)	printed circuit	printed circuit	printed circuit
Tubes	12AU7, 6AL5	same	same	same
Battery	1.5 V cell (supplied on early kits)	1.5 V “C” cell	1.5 V “C” cell, not supplied	same
Power	105–125 V, 50–60 c/s, 10 W	same	120/240 V, 50/60 Hz	120/240 V
Probe	three separate leads	combination AC-OHMS-DC switching probe	same	same
Cabinet	7⅜ × 4 11/16 × 4⅛ in	same	7⅜ × 4⅝ × 4¼ in	same
Shipping weight	7 lb	5 lb	5–6 lb	5 lb

Sources: V-7 manual, V-7A manual, IM-11 manual, and the 1972, 1976 and 1978 catalogues.

6.2 Full specifications: the Deluxe Service Bench models

Table 2 — Full specifications: the Deluxe Service Bench models

	IM-10 / IM-32	IM-13	IM-28	IM-5228
Years	1961–62 / 1962–63	1963–1969	1969–1977	1977–1989
Layout	vertical	horizontal, gimbal bracket	horizontal, gimbal bracket	horizontal, gimbal bracket
Meter	6 in, 200 µA, seven scales	same	same	same, new style face
DC ranges	1.5, 5, 15, 50, 150, 500, 1500 V (true √10 steps)	same	same	same
DC input resistance	11 MΩ (1 MΩ in probe)	same	same	same
AC input impedance	320 kΩ / 30 pF (early IM-10); 1 MΩ / 30 pF thereafter	1 MΩ / 40 pF (plus ≈160 pF of lead)	1 MΩ / 40 pF	1 MΩ / 40 pF
Extra AC scales	separate 1.5 V and 5 V red scales	same	same	same
Decibels	−10 to +65 dB, 10 dB steps between ranges	same	same	same
Accuracy	DC ±3%, AC ±5% of full scale	same	same	same
Frequency response	±1 dB, 25 c/s – 1 Mc	same	same	same
Rectifier	selenium 57-22	silicon 57-27	silicon	silicon
Pilot lamp	#47 in jewelled holder	neon assembly	NE-2E in lens	NE-2E in lens
Fuse	¼ A (IM-10); ⅛ A slow-blow (IM-32)	none	none	none
Mains	120 V primary	120 V primary	105–125 / 210–250 V	105–125 / 210–250 V
Calibration access	cabinet off	three front-panel holes	same	same
Size	9½ × 6½ × 5 in	5 × 12 11/16 × 4¾ in	same	same

Sources: Eckweiler, Heathkit of the Month #110; IM-13 manual; the 1961, 1967, 1972 and 1980 catalogues.

6.3 The early models at a glance

Table 3 — The early models at a glance

Model	Tubes	Rectifier	Meter	Ranges	Notes
V-1	6SN7, 6H6, 6X5	6X5 tube	small, 500 µA	5 voltage ranges to 1000 V	two cells for the ohmmeter; 8 lb shipping
V-2, V-2A	6SN7, 6H6, 6X5	6X5 tube	200 µA	6 ranges	sixth range added, 10 V and R×10M
V-4	6SN7, 6H6	selenium (V97)	larger	6 ranges	AC balance control added
V-4A	6SN7, 6H6	selenium	4½ in, 200 µA	6 ranges	revised AC circuit; ½% dividers advertised
V-5	12AU7, 7A6	selenium (V123/57-1)	4½ in	6 ranges	formed cabinet; single 1.5 V cell
V-5A	12AU7, 6H6	selenium	4½ in	6 ranges	7A6 abandoned
V-6	12AU7, 6H6	selenium	4½ in	7 ranges, 1.5–1500 V	R×100K added; “reversed diodes” tube selection

Sources: Eckweiler #19 and #84; V-2, V-4, V-5A and V-6 manuals.

6.4 Prices, catalogue by catalogue

Table 4 — Prices, catalogue by catalogue

Catalogue	Table-top	Bench	Wired version
December 1949 flyer	V-4, $24.50	—	—
January 1951 flyer	V-4A, $23.50	—	—
September 1951 flyer	V-5, $24.50	—	—
Winter 1955 flyer	V-7, $24.50	—	—
1956 catalogue	V-7A, $24.50	—	—
1959 catalogue	V-7A, $25.95	—	—
Fall–Winter 1961	IM-11, $29.95	IM-10, $32.95	IMW-11, $46.75
Fall–Winter 1962–63	IM-11, $24.95	IM-32, $32.95	IMW-11, $46.75
1967 catalogue	IM-11, $24.95	IM-13, $32.95	IMW-11 $39.95; IMW-13 $49.95
1970 catalogue	IM-18	IM-28, $39.95	IMW-18, $48.95
1972 catalogue	IM-18, $29.95	IM-28, $39.95	IMW-28, $59.95
Spring 1976	IM-18, $36.95	IM-28, $46.95	SM-20A $70; SM-21A $90
Fall 1978	IM-5218, $44.95	IM-5228, $54.95	SU-5218 $110; SU-5228 $120
1980 catalogue	IM-5218, $49.95	IM-5228, $59.95	SM-5218 $95; SM-5228 $120
1983 catalogue	—	IM-5228, $79.95	—
Fall 1985	—	IM-5228, $79.95	—
Fall 1987	—	IM-5228, $89.95	—
Christmas 1989	—	IM-5228, $129.95 (per Eckweiler)	—

All figures are kit prices from the catalogue scans at World Radio History except the last, which comes from Eckweiler #110. The Winter 1991 catalogue, which has a searchable text layer, lists no vacuum-tube voltmeter at all.

6.5 Accessories

Table 5 — Accessories

Part	What it is	Notes
309 / 309-A / 309-B / 309-C	RF probe, crystal-diode detector at the tip	1949–c.1970; 309-C rated 30 V RF, 500 V DC maximum
309W-C	Factory-wired 309-C	late production
310	10 kV DC high-voltage probe, ×10	1949 to mid-1950
336 / 336-W	30 kV DC high-voltage probe, ×100; 1090 MΩ 2% resistor	from mid-1950; wired version from about 1961
338 / 338-B / 338-C	Peak-to-peak probe, 5 kHz–5 MHz	1952 to about 1960
PK-3 / PK-3A, PKW-3 / PKW-3A	RF probe for the later meters	from early 1970; PK-3A from about mid-1979, kit version sold to late 1987
PKW-4	Wired replacement switching probe for IM-18, IM-28, IM-5218, IM-5228	1981 to late 1986
IMA-18-1	Solid-state plug-in replacements for the 12AU7 and 6AL5	instant-on conversion; 4 FETs and 2 diodes
IMA-100-10	×100 DC multiplier probe for 10 MΩ instruments	$14.95 in 1983
EF-1	”How To Understand and Use Your Vacuum Tube Voltmeter” course	$9.95; bundled as EF-1-3 (with IM-11) and EF-1-6 (with IM-28)

Sources: Eckweiler #118 and #119; catalogues of 1949, 1961, 1972, 1978, 1980 and 1983.

6.6 Related Heath instruments

The AC VTVM line — AV-1 (1951), AV-2 (1952), AV-3 (1956), IM-21 (1961), IM-38 (1969) and IM-5238 (1977) — amplifies before rectifying and is a different instrument for audio work; Eckweiler covers it in Heathkit of the Month #47 and #68. The solid-state voltmeters that overlapped with the VTVMs are the IM-17 utility voltmeter (1967–1977), the IM-16 solid-state volt-ohm meter and the IM-25 high-impedance VOM. The EUW-24 Science Series VTVM was a version built for Heath’s educational line.

6.7 Manuals and documents

Heath’s manual part numbers run 595-nnn, and later 595-nnnn-nn with a revision suffix. The list below gives every edition located online, with the data the project’s hosting rule requires. No copyright-renewal search has been carried out in the Catalog of Copyright Entries for any of these titles; “notice seen” records only what is visible on the scan examined here, and the absence of a notice in a poor scan is not proof that the printed manual carried none.

Table 6 — Manuals and documents

Title	Part no.	Date evidence	Copyright notice seen	Free scan
Assembling and Using Your Heathkit Vacuum Tube Voltmeter, Model V-2	not visible on scan	undated; V-2 sold 1949	none seen	archive.org
…Model V-4	not visible	V-4 sold from Jan 1950	none seen	archive.org · second copy
…Model V-4A	not visible	V-4A sold 1950–51	none seen	archive.org; schematic only
…Model V-5A	595-2	V-5A sold 1952	none seen	archive.org · second copy
…Model V-5 (schematic)	—	—	none seen	archive.org
…Model V-6	595-40	print date 11/13/53 on the scan	none seen	archive.org · second · third
…Model V-7	595-90	”Copyright 1954, Heath Company” on the cover; print date 2/10/55 inside	yes, 1954	archive.org
…Model V-7A	595-110	one printing carries “Copyright 1960” with print date 6/30/61	yes, 1960 (on the 1961 printing)	archive.org, DLARC · second · third
Assembly Manual, Service Bench VTVM Model IM-10	595-362	”Copyright 1960 9/9/60”	yes, 1960	archive.org, DLARC; schematic only
Assembly Manual, Vacuum Tube Voltmeter Model IM-11	595-486	”Copyright 1961”, print date 9/6/63	yes, 1961	archive.org, DLARC
…Model IM-11 (later printing)	595-486-1	print date 12/30/66	not legible on scan	archive.org
Assembly Manual, Service Bench VTVM Model IM-13	595-629	copyright line present; print date 1/11/65	yes	archive.org
Assembly Manual, Vacuum Tube Voltmeter Model IM-18	595-1154-05	”Copyright © 1968”	yes, 1968	archive.org, DLARC; partial
Valve Voltmeter Model IM-28U (UK/export)	not visible	—	none seen	archive.org
Vacuum Tube Voltmeter Model IM-5218	595-1972-01	”Copyright © 1977”	yes, 1977	archive.org, DLARC
Utility Solid-State Voltmeter Model IM-17	595-921-03	manual dated 11/10/1967 in one printing	not legible on scan	archive.org
Solid-State Voltmeter Model IM-16	not visible	—	none seen	archive.org
Science Series VTVM Model EUW-24	not visible	—	none seen	archive.org

No manual for an IM-32 or an IM-5228 was located online during this survey, and the V-1 and V-3 manuals appear not to survive in any public scan. The heathkitmanuals collection and the Internet Archive’s DLARC collection are the two places to check first; the DLARC scans are generally the better ones.

6.8 Catalogues consulted

Flyers and catalogues used in this dive, all at World Radio History: December 1949; January and September 1951; the 1952 catalogue; the 1954 Test Equipment catalogue; the Winter and Fall 1955 flyers; 1956; 1958 (Allied); 1959; Fall–Winter 1961; March 1962; Fall–Winter 1962–63 (the scan is filed as 1963); 1965 (800-55); 1967 (Allied); 1970 (800-03); 1972 (810-72); 1974 (810-74); Spring 1976; Fall 1978; 1980 (848); 1981 (854); 1983 (863); Fall 1985; Fall 1987; Spring 1988; Summer 1990; Winter 1991. The 1961, 1970, 1974, 1988 and 1990 scans have no text layer and were read as page images.

Further reading

• Bob Eckweiler, AF6C, “Heathkit of the Month” — the indispensable series, free for personal use. #19 V-7A and family · #110 Deluxe Service Bench VTVMs · #84 and #86 V-6 restoration · #78 IM-17 · #118 and #119 probes · index. Full schematics for the bench models are collected at w6ze.org/Heathkit/DSB.
• Brueschke, Ernest E., and Mack, Donald F., “The History of the Heath Companies”, AWA Review vol. 32 (2019). https://archive.org/details/thehistoryoftheheathcompanies — the standard company history; its V-7A board-thickness figures are internally inconsistent, as discussed in the overview volume.
• Chuck Penson, WA7ZZE, Heathkit Test Equipment Products — the reference for dating Heath test gear by cabinet style (Pre-Classic, Late Pre-Classic, Classic I, Classic II, New Look, Post New Look). Not online. https://wa7zze.com
• Rich Post, KB8TAD, “The Heathkit Legacy.” http://boatanchorpix.x10host.com/HLegacy.htm
• Heathkit Virtual Museum — pages for the V-7A and IM-11.
• Nostalgic Kits Central model matrix, useful for first and last catalogue years but with known errors in some dates. https://www.nostalgickitscentral.com/heath/products/alphabetical.html
• The Heath Company history dive on this site, for Benton Harbor, Daystrom, Schlumberger and the end of the kits.

Sources

All sources are linked inline above. The primary documents are the Heath assembly manuals held at the Internet Archive and the Heath catalogues and flyers scanned at World Radio History; the principal secondary source is Bob Eckweiler’s Heathkit of the Month series for the Orange County Amateur Radio Club.