• Country
• United States of America (USA)

• Manufacturer / Brand
• Grebe, A.H. & Co.; Richmond Hill (NY)

• Year
• 1922 ?

• Category
• Audio Amplifier or -mixer

• Radiomuseum.org ID
• 43555

• • Brand: Synchrophase

Click on the schematic thumbnail to request the schematic as a free document.

• Number of Tubes
• 2

• Valves / Tubes
• UV201 or VT-Class-II or A_Moorhead UV201 or VT-Class-II or A_Moorhead

• Main principle
• Audio-Amplification

• Wave bands
• - without

• Power type and voltage
• Storage and/or dry batteries

• Loudspeaker
• - This model requires external speaker(s).

• Material
• Wooden case

• from Radiomuseum.org
• Model: RORK Type 2 [Internal Rheostat Elements, thumb wheels] - Grebe, A.H. & Co.; Richmond

• Shape
• Tablemodel, Box - most often with Lid (NOT slant panel).

• Notes

• Grebe Type II Two-Stage Audio Amplifier Type RORK with internal rheostat elements with thumb wheel control. In 1923 the Andrae catalog R-3 recommended: 2xC301A for storage batteries or 2xC299 with adapters for dry batteries.

  The corrected schematic reflects the actual switch construction which is difficult to determine in the 1925 drawing. Values were determined from actual measurments.  Grebe vernier rhostats have an asbostos insulator so use caution. 

• Price in first year of sale
• 55.00 $ +

• External source of data
• Ernst Erb

• Source of data
• Radio Collector`s Guide 1921-1932

• Circuit diagram reference
• Rider's Perpetual, Volume 1 = 1931/1934 (for 1919-1931)

• Mentioned in
• Radio Manufacturers of the 1920's, Vol. 2

• Literature/Schematics (1)
• Andrae Catalog R-6 (1923), p.10

• Other Models

• Here you find 189 models, 127 with images and 62 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Grebe, A.H. & Co.; Richmond Hill (NY)