Midget stereo amplifiers–could they be today’s equivalent of those early low-power “general-purpose” amplifiers?

There has been a consistent range of affordable stereo amplifiers and receivers offered from the 1960s onwards that weren’t about high output levels or audiophile-level sound output quality. Here, they were about playing music from what was fed through them and yielding a decent-enough sound through a set of modestly-priced speakers.

Typically they were sold as something to have as the heart of your first multi-piece hi-fi system whether the system was with source equipment and speakers that you chose or as part of an affordable stereo-system package offered by the manufacturer. In some cases, the circuitry in some of these amplifiers has been integrated in one or more of the premium single-piece or three-piece stereo systems offered by that manufacturer.

Examples of these ranged from the Australian-built valve-based Cosmos stereo integrated amplifier that was sold through the Encel hi-fi store during the late 60s and early 70s, through affordably-priced Realistic stereo receivers sold by Tandy / Radio Shack through the 70s and 80s to the “micro” component systems that most of the Japanese hi-fi names launched through the early 1980s. This class of amplifier or receiver also represented the equipment that was offered at the lower end of a manufacturer’s product range.

In a lot of cases, these amplifiers and receivers were typically used as the heart of an elementary stereo system like one’s first hi-fi setup or a secondary hi-fi setup. Then the user’s needs would change towards using a better amplifier and these amplifiers ended up being used with a pair of cheap speakers to amplify sounds like game sound effects from a multimedia-capable computer.

But lately this practice has shown up again with the likes of Lepai, Topping and others who implement very small stereo integrated amplifiers that work effectively on a single chipset for both channels. Some of these amplifiers may have extra functionality like a phono stage, a digital-analogue converter, or a USB or Bluetooth interface as part of that same chipset or as another chipset that presents a line-level signal. But typically they are sold through different online stores as well as some specialist electronics outlets or hi-fi stores.

Here, these amplifiers are based on a TriPath “Class T” circuit design or a similar design which is based on the Class D switch-mode amplification approach that has allowed for highly-compact audio amplifiers. That is due to the ability to work with low current demands as well as not yielding excess waste heat.

Why are these amplifiers showing up again? Here, the low power output and the small circuit size has allowed for a very small footprint and one could easily connect them to low-powered speakers of which many are in circulation. One of the reasons this has This is brought about through affordable three-piece stereo systems that had given up the ghost and the speakers associated with these systems are seen as of value with a low-power amplifier.

There is also the fact that most, if not all, of the stereo speakers made before the 1970s were engineered for amplifiers which had low power outputs thanks to valve (tube) or early solid-state circuit designs that couldn’t achieve high output power. In this situation, these speakers including the floor-standing types were designed for maximum efficiency and an ideal tonal response while better amplifiers were designed for improved sound clarity.

A common application that these midget amplifiers are being put towards is to become an audio amplifier for your computer’s sound infrastructure. This is seen as being better than a lot of budget-priced active speakers pitched towards computer users which aren’t seen as offering high-quality sound.

Personally I would still value a stereo system based around these amplifiers as another direction towards a cost-effective music system where you don’t want memories of the gaudy 90s.

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