Ampeg has been a huge part of amplifier history, with amplifiers dating back to the mid 1940s that have been used by bands such as The Rolling Stones, Pink Floyd, Television, Booker T and the MG's, The Clash and others. Ampeg amplifiers have evolved over the decades. Being able to place specific products in their time period is a great way to assess value and impress fellow gearheads. Ampeg did utilize serial numbers when producing their amps, but these numbers can sometimes be inaccurate. The best way to date an Ampeg amp is based on its specific features and characteristics.
Dating Ampeg Amplifiers
Identify physical characteristics of the amp that could determine its era. The first generation of Ampeg amps were small bass combo amps, usually brown or blue in color. Their grill cloths were often a circular shape. Blue checkered grill cloths were '60s designs. Later amps from the '70s were made in more silver and blue or teal color schemes. Ampeg's latest amps, made after 1984, are usually all black unless they are reissue designs that are made to look like vintage amplifiers.
Determine whether the amplifier has a specific model name. Early Ampeg amps did not have model names and were only known as Ampeg (named after the Amplified Peg technology developed for upright bassists.) In the late '50s Ampeg started using model names such as Rocket, Mercury and Jet. They were tan colored amps. In the '60s and '70s Ampeg developed the Portaflex Amp, the B-15, the SVT, the V4 and the Gemini series.
Locate the EIA (Electronic Industries Association) code on the the pots of the amp. This is usually a 6 or 7 digit code that is a very accurate way to date the Ampeg amp. The first 3 digits of the code represent the manufacturer. The next one or two represent the last two digits or last digit of the year. The last two digits represent the week of the year.
Look up the EIA code in a reference book or website such as this one: webervst.com/codes.html. This will give you a very accurate date of your amp.