Gibson had been producing guitar and bass amplifiers for many years, but few had really broken through, at least in comparison with models by other US manufacturers like Fender and Ampeg. In the mid 1960s, the various variants of their bass amp, the Gibson Atlas had sold in moderate numbers; slightly better than the G-100 of the early 1960s, but still nowhere near as many as they should do. Gibson basses themselves didn't sell in especially large numbers, compared to their guitars, but the bass amps did worse still. For example, in 1965 Gibson shipped 2817 basses, and only 762 bass amps. Just a quarter.
So in 1967 they tried again, creating a new more portable bass amplifier, named Thor after the Norse god of Thunder. With a fat-toned Gibson EB bass it would surely rumble like thunder? In fact, an amplifier named Thor was available from late 1967 to at least 1975, though at some stage (perhaps as early as 1970, but certainly by 1972) the four tubes were replaced by solid state circuitry.
From the 1968 Gibson Thor publicity sheet
This is the new Gibson "Thor" Bass Amplifier. Even though it's only been on the scene a little while, it's already got a reputation: the big, deep voice in the small box.
The Thor was first listed in the September 1967 Gibson price list at $225. Shipping data for the Thor is only available for this, the first year, with 493 amps leaving the Kalamazoo factory - not the legendary Parsons Street plant though - in the 1970s Gibson had alternate facilities for pickup and amplifier production. Prices rose gradually to $250 in 1969 and $299.50 in 1971.
The design change from valve amp to solid state didn't make the amp any cheaper, however it did make it around 10% lighter, despite having a larger cabinet. In fact the 1970s amp was a little shorter than the 1960s version, but both wider and deeper.
From the 1974 Gibson Amplifier catalogue
Superb sound at a moderate price. The new Thor is a solid state bass amplifier that is rugged, versatile and portable. A 50 watt RMS power amp with 100 watts of peak music power available. Uses two heavy-duty, 10 inch bass speakers that add a lot of the highs today's bassists are after.
In 1972 Gibson added a larger model to the bass range, Thor's big brother, the "Super Thor". It had 65 watts to Thor's 50 - and two 15 inch speakers, as opposed to two ten inch.
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