Selling old, going digital direct ?

Selling Quicksilver 90 watt silver mono tube amps (20 years in great condition)... newer Quicksilver non-remote pre and Musical Fidelity M1 A DAC. Everything together weights about 112 pounds. I'm going to get a NAD C 390 DD integrated with DAC (17 pounds). Might lose sound but I'm 68 and there's big difference in weight. Also getting interested in computer audio...ripping, downloading HD tracks internet radio... It will be easier for me to figure it out with the NAD (not very computer savvy). Any thoughts? THANKS.
"Might lose sound but I'm 68 and there's big difference in weight."

What are you doing with your system, putting it away after each use? Just leave it on the rack and let it support the weight.

If it were my system to upgrade, I would keep the Quicksilvers and get a preamp and a dac, or just get a dac with a volume control. If you go that route, you will gain sound quality, not lose. (Providing you do a good job matching whatever new components you end up buying. You shouldn't have any problems. There's a lot of great products at all prices to choose from.)
The weight is not the main reason... I still work-out and swim laps 5 times a week, also still toughest guy on my block (why I moved from Chicago to AZ. I'm not trying to upgrade, just looking for a new toy to play with. I take reviews with a grain of salt... NAD C 390 DD got great reviews and I can throw it when I get mad. I'll be deaf or dead in a few years anyway... tubes are really hot in AZ even with central air in summer.
guy sez to gal "do you wanna 68?"
gal sez "what's a 68?"
guy sez "you do me and I owe you one"

If you want a new toy, get it first to try out before you get rid of old faithful. If you're looking for something to throw when you're mad, computers are better than stereo's.

68's the new ain't dead yet. You're more likely to get Alzheimer's.

I sort of new to higher end audio, but when I got into it, I had it in my head that I wanted an all digital front end with hi res capability. My target was HDTracks and all of the high resolution stuff that they had.

Now, a couple of years later, I gotta tell ya, it was a waste of time.

The largest component of what I had built in my head was the high quality music from HDTracks. Well, as it turns out, the stuff from HDTracks is hit and miss, at best. Most of it (the stuff that interests me) doesn't sound any better than what I get off of a CD.

If I had it to do over again, I would have spent more time picking out a good CD player, rather than setting up an NAS and getting a Sonos and a Squeezebox Touch.

I would still have gotten one or the other, but wouldn't have put all of my eggs into a streaming format basket.

If you have a killer system that sounds good to you, but want to dip your toe in the streaming realm, I'd suggest that you get something like a modified Sonos from Wyred4Sound and plug that into your DAC.

Spent the $30 or so and invest in dbPoweramp to rip your CDs and put them on a Synology NAS to store them.

I wouldn't put a big bet on setting up to play hi res downloads from HDTracks. The likelihood of being impressed is way too low.
My primary source will probably always be vinyl (4000 records) but I must admit I love the convenience (and simple enjoyment)of computer audio. My setup is very basic: laptop, Logitech Squeezebox going into a Monarchy Audio DAC. I use dbpoweramp to rip and JCRiver Media Center for playback and this all works fine. However, I do agree with Tonyangel's comment concerning the 'hit and miss' quality of HD Tracks' downloads.
As far as reducing the weight and complexity of your system, this makes perfect sense to me but only if you are prepared to accept that the resulting sound quality may not be quite up to the standards of your current system.

It's an interesting move you're making. An all digital chain invites digital signal processing ahead of the DAC. This includes bass management in the digital domain, room correction, etc. In other words, you will certainly have the option to do use DSP that IME will very likely improve sound quality, but I'm not sure that the NAD model that you've chosen will allow you the flexibility you need. (I'm unfamiliar with the specific model).

You might want to look at the HK 990 or NAD's own variation on the theme (I don't know their model designation) to explore the possibilities. The key is full DSP capability like that found in most HT AVRs. Even if you don't use it initially, you may find it intriguing down the road.

I'm 100% happy that I went down a similar route a few years back and my advice would be to buy as much DSP capability as you can afford.

Good Luck

Ive had good luck with HDTracks. Also B&W had a High Rez sitethat offers FLAC 24/192. Im looking into a streamer after ripping all my CD's and friends with about 9,500 tracks. Ive been streaming via Apple tv in my office to an Arcam R-DAC So Im in need of a good reference streamer and I think I found it in Accustic Arts. Im planning to go with their preamp and using my JC-1's for awhile until I can afford a good set of mono blocks.