I have Altec 19’s... so somewhat similar to your JBL’s.
Of the suggestions above, I’ve owned the Quicksilver KT Mono’s and the VAC 70/70 Signature.
The VAC 70/70 Signature is one of the best amps I’ve owned with regards to sound quality and overall appeal. It’s outstanding with jazz, classical and vocals... but probably not hard rock. It is an older amp and repairs would typically require shipment to VAC, which is expensive and time consuming (typically 6-8 weeks in my experience).
The Quicksilver KT Mono’s with Gold Lion KT88’s or. Tung Sol KT 120's are a solid all around choice. They are very dependable and focus more on quality construction than aesthetics. Sound quality is very good, but not elite (like the VAC 70/70 Sig that retails near $20K), which should not be expected from amps in the < $5K range. They are an excellent value new or used and often get overlooked due to their utilitarian aesthetics.
I’ve also auditioned a new Line Magnetic 845ia. The sound quality was excellent and I really wanted to buy it.. but the transformers hummed and buzzed significantly, so I had to pass on the purchase. In addition to the transformer issues I experienced, I don't think these would have enough juice for your speakers or musical tastes
While some scoff at the idea of McIntosh, I’ve owned the MC275 MKV and currently own MC-30 mono blocks. The MC-30's are wonderful from a sound quality perspective, but might be underpowered for your speakers. The MC275 is very enjoyable and would pair nicely with your speakers and varied musical tastes. As good or better than the MC275 are vintage MC-60 monoblocks... or MC-75's.
As far as pre-amps are concerned, I would immediately snag either of the deHavilland’s currently listed on US Audiomart. I own the deHavilland Ultraverve 3 and it’s the best preamp I’ve owned in 30 + years in this hobby. Don’t let the low price fool you... these preamps sound fantastic and respond well to tube rolling, which allows you to tailor the sound to your liking.
Also... in my experience, power ratings have to be taken with a grain of salt. A vintage push pull amp with 30 wpc can sound as powerful than a new Chinese amp rated at 100 wpc. Focus on quality construction, before looking at power ratings.