Dating vintage ampeg amps
The M-12 Mercury circuit of 1960 used 6V6 power tubes, but the Mercury circuit of 1965 used 7591As.
Likewise, an Ampeg from 1954 would not be covered in blue check vinyl whereas an amp from 1964 would have this covering.
Therefore, do not poke around in your old Ampeg if you are unfamiliar with amplifier electronics or their operation. Shortly after World War II, American electronic component manufacturers began to stamp a semi-standardized code into the parts they produced.
The code contained information regarding the manufacture and date of production.
The serial numbers are 6 digits in length with the following pattern: YMMNNN, where Y denotes the year, MM the month, and NNN the Nth unit produced that month.A final cross check with EIA dated components should remove any doubt about an made during the 1953 - 65 period.The second serial number system was implemented in January 1965 and used until the end of 1969.The serial numbers from these years were duplicated in 1963, 1964, 1965, and 1965, respectively.Taking the example Super Echo Twin above, its serial number alone could denote April 1954 or April 1964.