An early Vox AC80/100 with no control panel legends
An early AC80/100 with no legends on its control panel, continued from the previous page.
The only changes made to power section are the plate resistors on the output transformer's flying leads. At some point the original resistors went up in smoke, damaging a section of the tagboard.
The date codes on the Welwyn cement resistors used for the cathode bias and screen are "VA" = January 1964. The date codes on the Dubilier cathode bypass capacitors are "UK" = October 1963.
For related amps, see the main this page. The pictures below were taken in 2020. Click on the thumbnails for larger versions.
Detail of the underchassis. The date codes of the Welwyn cathode bias and screen resistors (respectively 270R and 470R) are all "VA" = January 1964. The date codes of the Dubilier capacitors are "UK" = October 1963.
Detail showing the missing section of tagboard.
The date code "UM" = December 1963 is just visible at the rim of the capacitor clamp.
Two of the EL34s are original - yellow-print Mullard xf2s with date codes "KG" = July 1963 for the application of the print, and "B3F3" = 3rd week of June 1963, for the manufacture of the valve. The other two - white-print Mullard xf4s - are from 1970 (date code "B0H1").
On all three transformers the Woden part numbers and date code has been deliberately removed. Above the mains transformer, which will have read: 72191 M.U. (or perhaps L.U.).
One of the original Mullard xf2s - date code (for the manufacture of the valve) "B3F3" - ready for sale in July 1963.
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