I acquired this set in the 80's and have coupled (too) rare JBL 4320 studio monitor speakers. The very high efficiency of the latter makes the large pool of redundant power amp and offers a response it is better to temporize by an equalizer if it has a reduced volume. If I do not consider that the preamp offers anything special, the amplification stage is really of great clarity and I quite agree on the principle of a direct source still enslaved by good sound Shaper ADC II, the benchmark EQ professionals ... The clarity and linearity of the distilled low cocktail LV 504 (or 502 which is the version without the huge VU meters) and are then JBL 4320 copies.
If it again, I would simply less power, would spend a small tube amp ... and above would keep the JBL!