Good starter amp recommendation

I don’t think you’re gonna get the gains you are hoping for by simply adding an amplifier. I think your best bet would be an integrated with an HT bypass. Get the receiver out of the chain completely for music. There’s a Naim Nait 5si on Agon right now for your budget. It should be great for what you’re wanting to do.

PS Audio Stellar Stereo or MonoBlocks M700..

To update the thread, I found a good deal on a used McCormack DNA-HT1 Deluxe. Will try it out and see how it works in the system. From what I've read it's basically a dual DNA 0.5 with a bridged center. Also, seems like a lot of people had a success upgrading the amp through smcaudio later on if needed.

If that is anything like the DNA .5 then you lucked out, as that is one of the best sounding SS amps on the market. Very involving, full-bodied and dimensional, with a sound to rival even a lot of really good tube amps. 

Don’t know the other amps but I can vouch for the Parasound A23. It is a real power amp. I was surprised when I first got it, I hooked it up to Dynaudio Focus 340s which are usually hooked up to a Simaudio power amp. The a23 had absolutely no problem dealing with the 340s, they just sang.

The a23 is now hooked up to Focus 160s on a different system. It is very musical and sounds great.

You will need a preamp though, since it not an integrated amp. Maybe your denon has a preamp out feature.

The a23 does run a little warm even if it is not active. I leave it on all the time. It needs a bit of space to breath. 

If you are looking for a good inexpensive power amp, the a23 is exactly that. And its physical size is also impressive. Given  what it can do, it is quite small.