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History of the manufacturer  

AVO Ltd.; London

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Name: AVO Ltd.; London    (GB)  
Abbreviation: avo
Products: Model types

The company was started in 1923, and was known as the 'Automatic Coil Winder and Electrical Equipment Co.' located at Douglas Street, London SW1”

Later they renamed to 'AVO Ltd.' (which should not be mixed up with 'Avo International Ltd.')

AVO is well known for it's very solid and reliable measuring instruments, and - coil winding machines.

AvoMeter is a British trademark for a line of multimeters and electrical measuring instruments,
The brand is now owned by Megger Group Limited.

The invention of the first multimeter in 1923 is attributed to Scottish British Post Office engineer, Donald MacAdie.

The Automatic Coil Winder and Electrical Equipment Company (ACWEECO), founded in 1923, was set up to manufacture the AvoMeter and a coil winding machine also designed and patented by MacAdie.

Support for AVO coil winders now by 'Cranleigh Coil Winding Equipment Ltd.', The Common, Cranleigh, Surrey UK, Tel. 01483 273536 

Founded: 1923
Closed: 1989

Donald MacAdie, a Post Office engineer, dissatisfied with having to carry many separate instruments, invented a meter that could measure Amps, Volts and Ohms - the multifunction meter was named AVO. MacAdie took his idea to the Automatic Coil Winder and Electrical Equipment Co.
The first AVO was put on sale in 1923, initially a DC-only instrument.  Although a shareholder of ACWEECO, Mr MacAdie continued to work for the Post Office until his retirement in 1933. His son, Hugh S. MacAdie, joined ACWEECO in 1927 and became Technical Director.

1939 Additional premises at AVOCET House 92 96 Vauxhall Bridge Road

1957 Name changed to AVO LTD.

1957 Became public company: Avo Ltd, of Avocet House, Vauxhall Bridge Rd, London, to manufacture instruments with the AVO trademark.

1958 Metal Industries Ltd acquired Avo Ltd, including its subsidiary Taylor Electrical Instruments Ltd.

1966 Moved to new premises in Archcliffe Road in Dover.

1967 Metal Industries Group, MIG was bought by the Thorn Electrical Industries group who quickly became part of EMI

1970’s Various companies were bought and moved to the Dover site including:

  • Foster Transformers
  • Evershed
  • Megger Instruments

1987 Renamed Megger Instruments Ltd

1991, due to the popularity of the AVO products the company changed the name to AVO Megger Instruments Limited.

2000 the company became known as AVO International Holdings Limited.

2002 as AVO International Limited.

Finally the whole Megger group changed its name to Megger Group Limited in 2002, as it is known today.

[Wikipedia 2017]

Some models:
Country Year Name 1st Tube Notes
GB  51 Valve-Tester 160 EAA91  Alternative valves D77 or CV140. 
GB  50 Wide-Range Signal Generator Mains model L63  Frequency range: 50Kc to 80Mc in 6 bands. There is also a "battery driven model" of this ... 
GB  50 Valve Characteristic Meter (VCM) Mk-III (Mk3) D77  Only original design with two tubes. Scheme now shows 6 diodes. 
GB  56 Universal AvoMeter (AVO Meter) 8 Mk.ii (2)   Model 8 UNIVERSAL AVOMETER Mk. II (from 1960 advert) "This instrument has been pro... 
GB  48 Universal AvoMeter (AVO Meter) 7 Mk.ii (2)   Model 7 Universal AvoMeter MKII. New movement design but no external changes initially.... 
GB  64 Universal AvoMeter (AVO Meter) 8 Mk.iii (3)   Front Bakelit, Gehäuse Eisenblech. MK III ist die verbesserte Version von MK II (zus... 
GB  63 Valve Characteristic Meter (VCM) MK IV (MK4)   Data Manual is "FIFTEENTH EDITION, 1963" 
GB  50 Valve Characteristic Meter MK2 (MKII) EA50  Röhrenprüfgerät 
GB  38 All Wave Oscillator [Mains powered] L63  The All Wave Oscillator is an accurate modulated oscillator suitable for all radio service... 
GB  66 VCM 163, Valve Characteristic Meter V.C.M. 163 2N2926  Contains 14 Valve bases, two large measurement instruments. 
GB  51–56 Universal AvoMinor (AVO Minor Meter) 2   Multimeter: Spannung: (4kΩ/V) DC: 2mV ... 5, 25, 100, 250, 1000V AC: 100... 
GB  67 Universal AvoMeter (AVO Meter) 8X Mk.iii (3) [Panclimatic]   Shape: Rectangular; Ranges: DC 2,5...2500V / 0,00005...10A; AC 2,5...2500V / 0,1...10A; Oh... 


Further details for this manufacturer by the members (rmfiorg):

Source: Wireless World 4/1940tbn_uk_avo_wireless_world_1940.jpg
Wireless World Sep 25, 1929, Page A8. worldradiohistory.comtbn_uk_avo_wireless_world_sep_25_1929_page_a8.jpg
Wireless World Mar, 1939, Page A1. worldradiohistory.comtbn_uk_avo_wireless_world_mar_1939_page_a1.jpg
Wireless World Aug 19, 1932, Page 14. worldradiohistory.comtbn_uk_avo_wireless_world_aug_19_1932_page_14.jpg
Using the Douglas Large Multi-Winding Machine. Australasian Radio World May, 1948, Page 31. worldradiohistory.comtbn_uk_avo_australasian_radio_world_may_1948_page_31.jpg
Wireless World Dec 7, 1930, Page A3. worldradiohistory.comtbn_uk_avo_wireless_world_dec_7_1930_page_a3.jpg
Wireless World Jun, 1961, Page A1. worldradiohistory.comtbn_uk_avo_wireless_world_jun_1961_page_a1.jpg

Forum contributions about this manufacturer/brand
AVO Ltd.; London
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Obituaries of Donald Macadie, MBE, inventor of the Avometer
Gary Cowans

Obituaries of Donald Macadie, MBE, inventor of the Avometer.

Extracted from Wireless World April 1955, Page 156.

Donald Macadie, M.B.E., the inventor of the original DC multi-range amps-volts-ohms meter, which later became known as the Avometer, died at the age of 83. After his retirement from the Post Office in 1933, he devoted a considerable part of his time to the activities of the Automatic Coil Winder and Electrical Equipment Company which he helped to form in 1923 to manufacture the Macadie coil winder and the Avometer.


Extracted from Wireless World May 1955, Page 265.

DONALD MACADIE, MBE. We regret to announce the death of Donald Macadie, M.B.E., the inventor of the AvoMeter.

He was born in the county of Caithness in 1871, came to London at an early age, and joined the Edison-Bell Phonograph Company, later transferring to the National Telephone Company with whom he worked as an engineer in Liverpool and Nottingham. In 1932 the M.B.E. was conferred upon him and he retired from the Post Office in the following year at the age of 62.

AVO Ltd.; London
End of forum contributions about this manufacturer/brand


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