suggestions on upgrading my system

I believe the weak link might be the phono/preamp stage in your integrated.  Obviously different ways to attack this. Maybe getting a outboard phonostage 1st. Also can the amp be separated from the pre in the HK?

What is your upgrade budget? 

I just checked, underwoodwally is selling the JD9MKII for $649 on AG. Check out the ad and maybe give him a call. I have no affiliation, however have talked to him and found him helpful. May offer a return policy. 

I believe that for $2000 spent in the AG marketplace could replace the HK with a better integrated. The question then becomes wether you get one with an internal phonostage.  If you like the idea of a separate phonostage, which is the way I would go, you could purchase one now and grade the HK later if you choose, after listening to your system with new phonostage.  The added flexibility may prove beneficial down the road..

I once owned a Jolida JD9 and thought it to be a great one in its price range. Phonostage/cartridge compatibility in important. The JD9was very flexible in gain and loading. It can be upgraded (factory or otherwise). The JD9 does not come up for sale on AG very often.

You might start another thread requesting advice on phonostage suggestions. Mention your system and cartridge when you do. 

Good luck!

After further exploration on the HK990, it appears that it has eq and bass management features that are in the digital domain only. As your are using analog input only you are not taking advantage of this, or if you are, you must be redigitalizing (spelling?) your analog signal to do so.  I have noted that your amp is considered very good as an analog 2-channel amplifier. 

So again, i believe you might find yourself very satisfied with your sonics with an improvement in your phonostage. You may later consider a cartridge upgrade also.

You are most welcome!  Keep us posted as to your decisions.