Help with $600 to $800 integrated amp

NHT has a loyal following...but if you are switching to 2 channel sound...they are a bit bright for my tastes...and because of their load..dont work that well with affordable tube gear(which would reduce some of the harshness)...they are pretty good for HT in your current configuration...but since you asked about upgrading both speakers and amplification...here it goes...

When I was auditioning monitors awhile back...I checked out the 1.5s you own...and did an a/b against other $600 monitors...the Paradigm Studio 20 and the Monitor Audio Silver 4i...and what struck me with the NHTs was their "Focused Geometry" slanted baffle..for whatever reason...the soundstage never went outside the speakers...like it did with both the Paradigm and the MA...
in short...they sounded a bit closed in...very good imaging between the speakers...but little "out of box" imaging from the outside...the NHT had the better bass...not surprising since they are a sealed design...test disc was MFSL "Darkside of the Moon"...I ended up passing on all three models...mainly due to metallic tweeter issues...

I guess the best advice is take some time and listen to some speakers...find a speaker you like...then worry about the amplification...the NHTs are by no means "bad" speakers...I tend to put a high emphasis on soundstage abilites...others prefer detail,imaging,transparency,or a combination there of...you have to find what you want out of a speaker...and hopefully one exists that meets all or most of your criteria...good luck

For around $500 used...Vandersteen 1cs speakers are tough to beat...they are pretty forgiving on electronics...you could get away with your NAK for the time being...but to get a full range(40hz) phase correct speaker for this kind of money is absurd...they will also have enough bass if and when you decide on a sub...they go alot lower than their LF specs would indicate...their soundstage and 3-d imaging is vastly superior to your current 1.5s...sell those for $250...get the 1cs...upgrade to an intergrated amp of your choosing (the Vandies dont require alot of power)...and watch your friends jaw-drop when they come over....they are not their best on aggressive rock...but for laid back jazz/electonica you mentioned...they would be perfect///

I picked up an Arcam a65 plus about a month ago. Im using it with PSB Alphas and a Music Hall cd player (rebadged shanling). The sound is pretty good with acoustic music and hip hop and disco, faster stuff might be overwhelming. Low level listening leaves a lot to be desired. This set up needs to be cranked up a little bit to get the best sound, and the Alphas are very efficient (91dbs I think). I know, I know I need better speakers, but no cash right now. I like the Arcam. One note, it doesnt weigh much and doesnt seem very sturdy, otoh my cdp weighs a good 17lbs!

SCD112, what I did to improve my stereo system was I got a hold of an Audio Aero Prima integrated amp. This is an earlier version with 3 inputs and an pre-out for a sub or another amp. I purchased this amp last year, bought a new Mullard tube and a Vandenhal power cord last year all for under a grand. The new Prima's sound nice, but this older model sounds just as good, or even better with the upgrades that I made. The cord really gave it tighter bass and the tube improved the midrange and highs. With the pre-out, which the newer ones do not have, makes it more applicable to use with a sub. This is a hard to find amp, if you do find one, grab it and do what I did and you will not be sorry.