Integrated Amp recommendation for $300 that will balance well with Vandersteen and NAD

It's your  $300 ceiling that is an arbitrary but severe limiting factor  in your quest and anybody offering up meaningful suggestions. At $300, the differences and improvements between choices are largely absent in a general "pick 'em" arena of contenders and pretenders.

I had the very same NAD C370 and C542 kit in a prior "B" system (With Totem ARROS and Chord cables) so I know the NAD component strengths and warts very well. IMO your C370 was among the better choices in your current price strata and will best most receivers hands down....full stop.

When it comes to that ethereal system synergy that you are currently lacking, the main non-fixable "wart" against them is their signature NAD sound (you already saw it .....amp AND cd ....) that does not marry well with a not-insignificant number of electronics, speakers, AND cable brands .

The second "wart" against the C370 that IS largely fixable was two mods:
(1) changing the stock uber- crap soldered-in "zip" power cord and
(2) changing the really crummy stock as-cheap-as-you-can-go preamp jumpers.


I had the stock power zip chord professionally dremmelled out in favour of a quality female IEC and external power chord . Big difference. 

Also I replaced those ultra-POS cheap metal jumpers with short run RCA terminated interconnects. Again, a step up.

These two mods together helped tame that "dark" overtone and sharpened the overall performance. ....the improvements  were not subtle.

IMO..... if you accept a higher price ceiling to  say, to a $500-$1000 range for an integrated amp (fuhgeddaboud any receiver with their crummy power supplies and dodgy stats that are already well publicized ) then the available integrated amp suggestion list becomes exponentially meaningful.

The degree of improvement in audio performance in this step-up price point strata that you are craving is not insignificant. These units are all built to a pricepoint and you only get what you pay for.

Postscript on the C370 price point as a comparison

let's not forget that this integrated amp new was $1000+ before taxes and inflation 10-odd years ago ...... The $300 suggested budget ceiling by the OP is at the extreme low end of this unit now in used condition before mods, and expecting "better" at $ 300 is a tall order IMO

Yes, $300 is tough, personally, id recommend to try to save to more like $500 and look at the likes of an Audio Refinement or a Myriad,  both can be had at that price and both are clearly Audiophile material... If not,  Teac makes a sumpin sumpin 301 that's decent... that will run $300 to $400.  If you don't care about a remote, there are several Chinese integrates that are tubes or hybrids that are pretty good too.
I hope this helps,
Tim

The NAD C317 is the best integrated that NAD has ever made up until that point. You should be able to pick one up for a few hundred bucks. My son uses mine (thankfully) so i know it's in good hands. A true classic.

I picked up a Marantz PM8004 for $425 and could not be happier with its detail, extension and dynamic range.

I agree you should stretch your budget a bit.