Info about dating
I have not yet managed to collect enough information on the later models carrying the Hiwatt brand and manufactured by Turntone or Sterling, e.g. The serial numbers of these newer models often fall within the ranges listed below, but these were manufactured in the mid-80s and later.Turntone started the "L" series of amps in 1985 or so, and these have no manufacturers brand on the serial plate, but say "Made in England." Amps made by Sterling Imports were made in California, USA, and have that brand name on their serial plate."Let's all make a pact to not get into a relationship!Let's keep having sex with random girls and never fall in love! " It's such a dumb premise, and it's like the script keeps wanting you to hate these characters until they "redeem" themselves by the end but again, it's so artificial that you don't buy a second of it.
The numbers listed below are within a year or so of when the actual date of manufacture occurred.
Other information has been obtained by personal accounts from individuals and via the Hiwatt registry. Note that manufacturer date codes stamped onto the original internal parts can be used to positively establish a "not manufactured before" date.
The parts were likely manufactured one to twelve months (sometimes longer) before being used to build an amp or fill a speaker cabinet.
All units manufactured by Hylight Electronics from 1966 to 1981 had a serial number plate like the ones in the pictures below attached to the metal chassis of the amplifier.
All of these plates bear the marking All units manufactured by Hiwatt Biacrown from late 1981 to 1984 had a serial number plate like the one in the picture below attached to the metal chassis of the amplifier.
The Hylight/Biacrown transistion numbers are particularly vague, as Biacrown likely used up the existing supply of Hylight plates before ordering their own.