Upgrade path

Too many variables to consider before throwing out what amp may give you a little more slam. Used to work at the local Dunlavy shop part time back in the days. The SC4s are ruler flat so if your looking for a big fat bottom you may never get there. Your room size has as much or more to with it. We also sold the ARC LS3 and that was a really good preamp but there’s much better today. I’d look at my speaker placement, do you have dedicated circuits to your equipment which your amp really needs to get the most out of it, and lastly if you don’t have revealing cables that can deliver the goods then I’d start there with dedicated lines. The SC4s are big heavy boxes to move around so wondering if you have the spikes in the plinths?

Yes the Dunlays are pretty nice. Not looking for a fat bottom end. Just looking to tie everything together.I will continue to look for a better pre amp... As more than likely there lies the key. Will a tube preamp soften the bottom end? Also any recommendations either tube or solid state for preamps? Would need a pre with two sets of main outputs so I can continue to bi amp.

It seems like you're overall happy with the sound you're getting but just looking to augment the bottom end a bit.  That seems to be common with your speakers and what the SC4a may have addressed.  I doubt spending $4k on speakers, amp, or pre is going to get you what you seek without potentially compromising other areas.  If I'm you, I'd demo a sub with a good bass management system and see if that adds what you're looking for.  If that helps I'd then get a second sub and live happily ever after -- although I'd eventually replace the preamp as well.  Best of luck. 

If if you have the room: bigger Dunlavys,...or sub-woofers.

Thanks Soix, and unsound. One issue I do suffer from is that some tracks sounds mediocre in my system. others are a sonic bliss. My guess is that its the track/recording itself. Thought switching one of the 3 pieces out would give me more of a even tone across all my music. Also with the Dunlavy speakers Prior to getting the Dreadnaught amp I was running a set of Emotiva mono blocks 500watts while not the greatest of amps but they were good and controlled the bottom end of the Dunlavy's very well. I like the Dreadnaught a lot better. Night and day difference on Sonics and presentation, detail, and midrange. This is what gave me the thought that a higher wattage amp in the same league as the Dreadnaught or better would give me the total overall package??