You obviously have high regard for your Hovands and are quite pleased. Why not wait and see how well they mate with the new speakers? You may not wish/need to change anything.Different may not be better.
Personally I wouldn't change a thing... I've been enjoying a friends Hovland 100, paired with the Radia on a regular basis and it's a combo that hard to beat. (The Radia replaced some very nice EL34 mono blocks...)
Let your new speakers run in for a few months before changing anything, then and only then I would consider Crimson Musiclink cables and interconnects.
How big is your room? With Def4s, my preference is for P/P amplifiers over SETs, but I have a rather large room.
I also really enjoyed my Mcintosh gear, which probably sound more in the vicinity of your Hovland SS amp.
I'd personally try a tube amp and see what you think---since it's been since 2005, nothing to lose and if anything would cement your position with the Hovland for another 10 years if they don't work out.
I definitely agree with the consensus that I'll listen for a good few months before considering any possible change from the Hovlands. It's a pair of components that have really proved their worth in the last 7 years, and any alternative would have to be a significant step up, not just a moderate improvement.
I do feel that we audiophiles as a group are too ready change equipment without a clear view of where any upgrade may take the whole system.
Additionally I love the hybrid sound of the tube pre and SS pow, and love the design ethos of the Hovs.
Lamm Industries ML2.1
Tube amp with NOS 1970s Mullard CV4004 Box Plate made in UK, modified with Ultra Performance Parts inside offers timbal truth, a top to bottom coherency, explosive speed locked with a accurate and uncolored reproduction.
Sure and while Spirit is at it he can Motor down to Brighton and take a few of Peter's AN amps to take home and demo. These guys will make the Audion seem like Best Buy at best. And there's always Kevin's warehouse to vsit to grap some Kondo amps.
What say you Spirit?
Sorry, Glory, never found Lamm my cup of tea, a little too cool, when heard at shows, AN gear a little too euphonically warm for my tastes.
Both also a little out of my price range.
Will def investigate Berning and Audion when funds allow.
If money was no object, I'd love to audition Ypsilon and Robert Koda amps poss. thru Zu Dominance spkrs.
Just would like to hear from Hovland owners esp.