Tandberg 2060; Tandberg 2045; McIntosh 1900; Harman/Kardon 150+ quad; Marantz 2230.
Even with the wide-variety of wattage ratings, these models (to me: based-upon once having used them second hand) all had the ability to serviceably run old New England-type acoustic suspension speakers (A.R./KLH/Advent/EPI) good enough without imploding (which: a lot of receivers claiming to have higher power, often by the same brand, couldn't handle). Keeping in mind the axiom: budgeting for QUALITY SPEAKERS should *not* be left as an afterthought because THEY are what can make the sound of a less-than-top-of-the-line component sound better beyond expectations. If an amp, of at least 50wpc, CAN'T hack it connected to a pair of 4-ohm speakers in real-world conditions: the design of the output stage is maxxed out with a skimpy shoehorned-in power transformer not having a large enough secondary and it doesn't merit wasting money on (the "monster" Superscope built Marantzes going for ridiculous money now suffer from this; Sansui, by contrast, had far more robust power outputs to cope with inefficient speakers).
Pioneer, IMO, had one-note boomy bass and lacked detail unless used with "West Coast" speakers copying JBL's exaggerated midrange sound. Kenwood's vintage integrateds of the "KA" 8000 and 9000 lines (from 1978-1980) are far more worth looking into, because of their Accuphase-descended topology; than, say, mass-market Kenwood receivers would be from a similar era.