Welcome to my Apparatus Design Company collection. This site contains photos, manuals, and information about vacuum tube testers manufactured by the Apparatus Design Company of Little Rock Arkansas in the 1930's. The Apparatus Design Company was founded in the early 1930's by Jewell R. Williams after he left Supreme Instruments.

Jewell R. Williams

The Apparatus Design Co. (ADC) manufactured several models including the "Confidence" series tube testers, "ADCO" tube tester, and the "ABC Unameter" below. Please note: The data and files contained here are items I have collected from many vintage sources. There is no guarantee of the accuracy of any information contained on this page. It is solely up to the end user to decide that the information and files contained here are accurate and fit for use with their equipment. I am not responsible for any loss or damages that may be incurred from the use of this information. Some files on this site are in Adobe PDF format. You need Adobe Reader to view Adobe PDF files. Download it here (free).    When viewing larger photos, you can use your browsers back button to return to the previous page.

ADCO Tube Tester This small 3 socket tube tester selected tube settings with a series of short jumpers. The left dial sets the line voltage. Case measures only 6½"x13"x5½" Larger Photo Sorry, no data yet.

The Confidence Special Tube Tester This unique tube tester had one selector with 56 settings. The data sheet lists the tube socket to use and a number to set the center dial to for the vacuum tube to be tested. Larger Photo Download: Confidence #6 Data Sheet

The Confidence Automatic Model B Tube Tester This tube tester was also designed with one selector with 56 settings. This unit has the optional panel in the cover with an additional 10 tube sockets. Individual adapters were also available. Larger Photo Front Panel Name Plate Download: Confidence B #4 Tube Data Sheet & Instructions Tube data update for Models B & C #126 Adapter list and note Models B & C

The Confidence Model 36 Tube Tester Physically the largest of all the testers here, this Confidence Model 36, has one large tube selector in the center, and several controls and selectors for measuring DC volts, testing vibrators, and testing condensers. The case measures 11½" wide x 18¼" tall x 6½" deep Larger Photo Download: Confidence Model 36 Manual and Tube Data

The Confidence Master Tube Tester The Confidence Master, has four long slide selectors. The far right adjusts the tester for the AC line voltage and the other three are set for the tube under test using the chart in the cover. This is an AC powered tester but has the early lamp socket connection which was never changed a two prong plug. Photo 1 Photo 2 Download: Confidence Master Instructions and Tube Data

The ABC Unameter Tube Tester Another unique tube tester. Unlike the Confidance testers above that have one or more dial selecters, this Apparatus Design Co. tube tester like the Confidance Master, has four long slide selectors. The far right adjusts the tester for the AC line voltage and the other three are set for the tube under test using the chart in the cover. The case is long compaired to the width of the tester and measures 17½" x 9¾" x 5½" Larger Photo Download: ABC Instructions and Data Sheet

Confidence Bridgohmeter Unlike most multi-meters today, this unique ohm meter by the Apparatus Design Co. uses a "null" meter for measureing resistance. When the dials are set to the correct value, the meter pointer is in the null position. You then read the value off the dials, not the meter. Larger Photo Larger Photo (front panel) Download: Bridgohmeter Instructions and Data Sheet

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Please Note: The data and files contained here are vintage sources. There is no guarantee of the accuracy of any information contained on these pages. It is solely up to the end user to decide that the information and files contained here are accurate and fit for use with their equipment. I am not responsible for any loss or damages that may be incurred in any way from the use of any information contained on or downloaded from this web site.

This is a private collection.
This site is not affiliated in any way with the Apparatus Design Company of Little Rock Arkansas.
Copyright © 1995-2011 Steve Johnson, Auburn NY, All rights reserved.