Sorry for such a long wait between posts. One of the Ref 18's failed after a few days, and I had to send it in for repair. Mildly disappointing, but not unusual for a new product from Nuforce. The good thing is they are on top of it and fix issues very quickly these days.
It has been a crazy few months, with RMAF, hosting audio get togethers, and opening up a new outlet store for audiophiles, time has been a precious commodity.
Now its time to get ready for CES. Fortunately TweekGeek nor Audiophile Outlet Store is exhibiting, so there is a little more time for things like telling you about the Nuforce Ref 18.
I currently have had them in my system now for 48 hours running continuously, and they are improving. I love the low profile form factor and the fact that they generate no heat. My biggest concern with them in the beginning were the high frequencies, something about them was unsettling. Now things seem to have taken a turn for the better with time and a few tweaks. Let me just say Nuforce amps absolutely need quality AC. Do not think you are going to get away with plugging them straight into a wall, or a budget conditioner. You need something that filters and conditions the AC very well. AC Cables are important too, something that allows the gear to breathe, with instantaneous current delivery, but something that also possesses a warmer sonic signature, the same goes with speaker cables and interconnects. I prefer warmer sounding cables with the Nuforce. The Bybee AC products have always mated well with Nuforce gear. I am currently using the Bybee Power Purifier, and the Bybee Speaker Bullets. The combination is great with any system, but it takes the Nuforce products from competitive in their price range, to stellar. There is a special synergy that makes the Nuforce less electronic sounding, and more musical. They are not inexpensive, but worth every penny if you want to get the most out of the Ref 18's.
I also found the AudioPrism Ground Controls on the loudspeakers to be very beneficial. Again this is something that I have found to work on every speaker, but for whatever reason, they synergize particularly well with Nuforce gear.
What it comes down to is minimizing electronic noise. Switching amps are particularly prone to being noisy. The type of noise I am talking about is not necessarily audible hiss that you hear when you put your ear to a loudspeaker. In that regard these amps are stunningly quiet. The noise I am talking about seems to affect the way upper mids and highs are presented. There can be an "edge" to the sound that may at first appear to be enhanced transient response, but over time becomes fatiguing and is realized as being gritty or grainy. This is the Achilles heel of switching amps in my opinion.
The Ref 18's definitely have much less of a problem with this than the Ref 9V3, but they still benefit greatly from the Bybee AC conditioner, speaker bullets, and ground controls. What I hear when all of those are in place is what mid and high frequencies should sound like, effortless, natural, yet dynamic with excellent transients that don't make me want to turn down the volume after an hour.
In general, one needs to spend time with any component to really assess if it is a fit for one's system and preferences. Audiogon is littered with gear that had great reviews, was purchased site unseen because is was a "good deal", then quickly put back up for sale because the buyer had different preferences, it didn't synergize with their gear, or honestly their system sucked to begin with and they weren't addressing the problem. Is it really a bargain at that point?
So bottom line for today, the Nuforce amps need quality power conditioning, cabling that leans to the warm side, and the amps will also benefit from additional noise reducing devices placed near the end of the signal chain.
Next post, bass.