Why amps, pre-amps, integrated amps???

Then again, maybe not. The Harman Kardon were way more costly.

12-11-11: Hifihvn
Johnnyb53, who do you think made the amp.

Heathkit itself probably made the amp parts. It was sold in kit form only, so ultimate the purchaser assembled it. Heathkit had been around since 1912, and had started offering electronics kits in 1947, so by the time Zenith bought Heathkit in 1979 heath had a well-evolved design and manufacturing facilities. In fact, Zenith bought Heath to get a leg up on home computer technology as Heathkit had a thriving personal computer product line.

The AA-1600 was one of the first amps to take transient intermodulation distortion (TIM) into account. This type of distortion was so new to amp design that Heath's specs for TIM qualified the numbers as "after Leinomen, Otala, and Curl." This may have something to do with why it is such a departure in sound quality from the "classic" amps of the '70s and an intro the much better sounding amps of the '80s.

Heathkit itself probably made the amp parts.

Could have. But, in the past, they used transformers from companies like Acrosound, Peerless, UTC, and other upper brand transformers in their well known amps, that collectors seek. Sometimes they seek their old amps for these parts made by other companies. Not all of their products were kits. Even some of the speakers made by JBL.

The AA-1600 was one of the first amps to take transient intermodulation distortion (TIM) into account.

It seems they may not have been the leader in seeking ways to measure and work on this. [http://www.aes.org/e-lib/browse.cfm?elib=10255]
Maybe the good old no-feedback design was right in the first place.

Oh yes, Allied, Lafayette, Radio Shack, and others had amps and other products made for them also.

The 'TIM' amps of the late 70s and early 80s proved to be a dead end. What they proved was that you can go overboard chasing specs to the detriment of the final product.