Looking for integrated solid state amp for daily usage

Hegel H190. New ones can be found for about $2,800 if you search a bit (I found it at 2 sites), down from $3,900. Built in streamer and DAC (that is pretty good), 2 x 150 WPC, RCA and XLR analog inputs, good number of digital inputs, very highly regarded affordable integrated.....check out the hundreds of positive reviews.

I own both the NAD Masters M33 and the Krell K300i.   Both are excellent and well built.   The NAD is a bit more friendly as it also has a Blue-OS streamer built-in whereas the Krell requires an external streamer (Innuos Mini Mk3).   Sonically the Krell is magic and sounds to me a lot like a tube amp, warm, musical, and bass control that is super tight and deep.   I don’t think you could go wrong either way.

Marantz Model 40 if you want an all-in-one, do anything streaming amp. If you want to keep it strictly analog, the Model 30. Both of these are high end Marantz offerings, and it shows on both close examination of their build and close listening. The Marantz smooth, clear, and slightly warm sound is alive and well, and will pair nicely with your JBL 4309s, especially in a nearfield application. 

According to a review of the naim 5si, it’s said that it pairs well with the 4309’s. It’s form factor is a benefit, being that it is slim. Tube like, yea, no....

Yamaha A-S2100 or 2200 (2100 is slightly brighter but more resolving).

Both of these models get closer to replicating good tube sound than do the dozens of other SS amps I’ve owned and auditioned over the years. They achieve that “lit-from-within” midrange better than many tube-based products actually. Very unique voicing within the industry. Bass extension is also incredible—better than that of some $7K^ amplifiers.

The next best options of the above mentioned brands are Bel Canto, Ayre and Pass Labs. However, it will be difficult to find a good Ayre or Pass model within your budget, and the Bel Cantos don’t have the bass authority of the Yamahas, even the higher power models.

Hegel is about as bland and boring as SS gets. They don’t really do anything wrong per se, but are also unexceptional at everything. This is why there is never any shortage of Hegel amps on the pre-owned market. 
 

^ It’s the same for Luxman, NAD and Marantz, nothing remarkably unique or notable, but they sound less “ballsy” than the Hegels.
 

Generally you want an amp that doesn’t achieve its low distortion via large amounts of open-loop feedback. That’s why Ayre and Pass sound the way they do. The Yamahas are the only amps I’m aware of that employ a high feedback scheme (a rather uncommon circlotron circuit) yet still manage the tube-like sound. You get the strong lowest octave bass of a high feedback design but don’t have to sacrifice the gorgeous mids and tonal saturation of a low feedback class A amp. They offer better “hybrid” sound than most true hybrid setups.