A Vox PA50 (MC50/4) from 1967

Some pics of the preamp assembly of PA50 - properly speaking an MC50/4 ("MC" standing for "Metal Clad") - serial number 7595, early 1967. A number of date codes can be made out: potentiometer "LN" = December 1966; Hunts capacitors "UYA" = 9th week of 1966; Mullard mustard capacitors, one with "D6N" = last quarter of 1966. The ECC83s are Mullard "Foreign Made", code 165/46I4. The chassis is stamped "INSPECTED. No. 1. S.E.L."

The power section of PA50 (MC50) serial number 7597. The Hunts caps have date codes "YDU" and "UYD" = 8th week of 1966 (in UYD the year-letter is prefixed, in YDU suffixed). The transformers were manufactured by Drake: mains (1202-112B); output (784-125); choke (352-169). The main filter caps (made by CCL) are later replacements - date codes "J7" = October 1967, "B8" = February 1968.

The Hunts suppressor capacitor (across the rectifier bridge network) blew violently at some point, shorting out the power section - an easy fix.

The EL34s are probably the original Mullard Xf2s. The impedance selector is (from factory) a terminal block rather than a paxolin board with a selector screw. No bias pots were fitted (note the blanking plates in the pic immediately below).

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