Quality level of an audio system should be judged on the merits of its sound, not appearance, price, brand name, technical specifications or year of manufacture.

Geoff Kait
Machina Dynamica

A list of fine vintage gear. The Pioneer HPM-100 speakers have a JBL heritage as their designer was head of JBL engineering for 10 years before going to Pioneer. The HPM-100 was designed to last, no worry about replacing foam surrounds. If all of the equipment is in the condition you state, there is really no reason to replace any of it. Listen to it for a while and take some time to take your ears to audition new equipment before committing to a change.

The ADC Sound Shaper III, Mk II Equalizer, Realistic APM-300 Power Meters and Pioneer SR-303 Reverberation Amplifier are really not necessary and just will add potential noise to the system chain. Possible improvements might be a new phono cartridge and servicing the cassette player. I'm still impressed by my older cassette player with the still available Maxell XLII 90 tapes. Five packs are just $10 on Amazon.

The Athena Technologies AS-F2 are well regarded and should be A/B evaluated against the HPM-100s to see which wins your ultimate approval.

For a new integrated, perhaps a refurbished NAD C375BEE from Spearit Sound for $950.