Vintage Triplett Equipment

Triplett of Bluffton, Ohio is most famous for multimeters, panel meters and tube testers. When the company switched over to digital multimeters and specialized testers, the demand for the traditional analog equipment continued so they still carry both types. Founded by Ray Triplett in 1904 and continued as a family run business until 1984. As of 2007 Triplett is owned by the Jewell Instruments LLC (originally founded in 1899). The famous Triplett 630 series continues on into the 21st century.

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Standard Triplett Multimeters

Triplett 630 Multimeter (VOM) 1940-1980's. The most famous Triplett Analog Multimeter
Triplett's version to compete with Simpson 260 series VOM's. Simpson was clearly the leader in this one category, but Triplett kept trying to sway buyers by tauting features with a better price. Used 2 batteries, a 1.5V D cell and a 30V Eveready 430 cell (no longer made need to substitute either three 9V batteries or an Excell 30V akaline replacement). 20,000 ohms/volt sensitivity. The 630A was the 630 with a mirror scale to reduce parallax view errors.
Triplett 650 (VTVM) late 1940-1950s: Built on the famous 630 bakelite cabinet. This model unlike most VTVMs (Vacuum Tube Voltmeter), has a real AC/AC RF probe. Uses a Tube detector built into the probe (industrial 6AL5 tube). According to Triplett good up to 150 MHz. This model is about 3/4 inch deeper than the 630 VOM. 11 megohms/volt sensitivity. VTVMs were replaced by transistor voltmeters (TVMs) by the 1970s, which were replaced by digital voltmeters (DVMs) Replaced with the model 850, a larger meter face, lower voltage ranges but they dropped the RF probe. Sensitivity 11 megohms/volt.






 Making the AC-RF probe for the VTVM. Uses an industrial grade 6AL5 as the diode detector. Good up to 150 MHz. Not shown is the cable connection to VTVM via BNC cable (don't use foam dielectric will not work for measurements above 600V) to Amphenol 2 PIN male screw on mike connector 80MC-2M.

Compact Triplett Multimeters

Triplett 310 (Mighty Might) Type 4 (current model 310C), compact multimeter.
 The 310 series has been around since the 1960s and is still in production today. Today all the different versions Type 1 to 5 are now the 310, 310C and 310TEL. Requires 1.5V N Cell and 15 V Eveready 504 Battery (obsolete). The newer 310C still uses the N Cell but replaced the 15V battery with an alkaline 12V battery commonly available at most stores. Sensitivity 20,000 ohms/volt.
ABOVEThe 1.5 V Alkaline N Cell is available at industrial electronic stores, The 15 V Eveready 504 can be substituted with 9 Eveready 357 (AG-13 or LR44) 1.55 V Button Cells in series shown.

Triplet 666-R Multimeter (VOM) 1950-1970s: Compact VOM Rated 1000 ohms/volt
VOM stands for Volt Ohm Milliammeter. The VOM was used for making non critical voltage, resistance and current measurements, but for voltage measurements that are critical a vacuum tube voltmeter is needed. This one is 1/2 the width of their famous 630 Bench VOM. 1,000 ohms/volt sensitivity.

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Triplett in 21st Century

They continue to produce analog measuring multimeters, and since the mid 1980's expand the line of digital multimeters. They produce very specialized portable field testers for a variety of industrial needs.



Triplett 9045 True RMS Digital Multimeter (intro 2014), CAT II and III compliant. Price range $80-100.
This model has autoranging self adjusting range, avoiding out of range area common in analog and basic multimeters. Also features backlight, audio continuity test, 10 MHz frequency counter with duty cycle measurement, capacitance tester, diode check, max/min data store, bar graph comparison and temperature measurements.

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