1
ST-70, Mark II, Mark III and Mark IV - to check your date of manufacture on Fri Apr 10, 2009 8:15 pm
Bob Latino
Admin
I recently had a customer ask me about the date of manufacture of his ST-70. There is a code on the bias pots that gives you a good idea of what year your amp kit was shipped out by Dynaco. This also works for the Mark II, Mark III and Mark IV amps. Below is the text of the Email that I wrote in response to his Email.
"Steve,
On the ST-70 you can check the 7-digit number stamped on the bottom of the BIAS POTENTIOMETERS. The 4th and 5th digits are the year of manufacture and the 6th and 7th numbers are what week of that year. If for example the bias pot is numbered 1386217 - then these bias pots were made in the 17th week of 1962 - probably in early May of 1962. Since Dynaco used parts very quickly you can almost be assured that this amp kit was shipped to a dealer in 1962. If your bias pot has a "48 to 52" as the 6th and 7th numbers like "1386249" then it is possible that the pot was made in 1962 but the amp was shipped out 5 or 6 weeks later in 1963.
See below a bias pot made in August of 1964 with a "1376430" code
Bob"
"Steve,
On the ST-70 you can check the 7-digit number stamped on the bottom of the BIAS POTENTIOMETERS. The 4th and 5th digits are the year of manufacture and the 6th and 7th numbers are what week of that year. If for example the bias pot is numbered 1386217 - then these bias pots were made in the 17th week of 1962 - probably in early May of 1962. Since Dynaco used parts very quickly you can almost be assured that this amp kit was shipped to a dealer in 1962. If your bias pot has a "48 to 52" as the 6th and 7th numbers like "1386249" then it is possible that the pot was made in 1962 but the amp was shipped out 5 or 6 weeks later in 1963.
See below a bias pot made in August of 1964 with a "1376430" code
Bob"
