Recommend an Entry Level Turntable (And maybe an integrated Amp)

I’m gonna ask a question:

can you keep this as a happy second system, enjoy it elsewhere, ... office, .... and start over piece by piece for a new music system?

IOW, new speakers, probably used to move up within your budget. That is the biggest improvement you will hear (first with the existing receiver and cd player). If not streaming, that marantz looks like a keeper.

then new or used components with the sources/inputs/features/remote controls you want. think long, sketch the ideal, then begin.

Any starter TT, it’s not the deck and arm difference: you will be hearing the cartridge, and it will be colored via the Phono stage. You need to find the combo that you like, that ain’t easy. Alignment skills for a TT/cartridge are paramount, who will do that?

Then, having an enjoyable TT, if you stick with Vinyl, move up with your then acquired experience and alignment skills. also think long, I went from a decent Audio Technica AT120 with a single great cartridge to a Vintage TT and Large Plinth with 3 arms/cartridges ready to go. Got there by accident with a lot of help here.

have a peek, 8th photo here

my good friend just went to a new arm with removable headshell and VTA on the FLY. IMO that is the best way to go with a single arm, it allows changing headshells with different cartridges easily, i.e. MM Stereo; MC Stereo; Mono. That is a commitment, after you decide you will move deeper into Vinyl

you could jump right in with this vintage JVC Victor two arm plinth, direct drive quartz locked TT81;

and Long 7082 arm with VTA on the Fly

that’s $1,100 usd, and sold by Vlad, the Russian in Canada I bought mine from and Bill subsequently got his from. I highly recommend him. note: he also has the standard length 7045 arm listed separately. If I knew what I ended up knowing, I would buy this and the 9" arm.

that JVC Victor plinth is big and heavy, check the measurements, I had to order a deeper glass shelf for it. 

Klimt,

Very good discussion and great advice from your A'gon friends.

I'm going to point the discussion in another direction.  I am in total agreement that a modern integrated will offer far superior performance than your Denon receiver.  The unknown factor here is the strength of the emotional attachment between yourself and the Denon.  My 40+ years of experience shows that this can be quite strong in many cases.  The daily "feel good" sensation you get from a piece of gear that was a loyal companion through some of the most important cycles of your life is impossible to place a value on vs setting it aside for something that delivers an improved listening experience.  Only you can make that determination.  That being said it is possible to significantly improve the performance of the Denon the degree where it doesn't sound like it came from the same factory.  Yes, "audiophile" characteristic are possible with significant improvements in warmth, detail, and overall musicality from the Denon. There are "mods" you can do at home if you're "handy" or the average hifi service tech can easily perform these.  Plan on spending between $200-$300 for a 40%+ performance improvement.  Will it match the performance of a modern integrated?  No.  But, it you want your old friend to look the same, operate the same, and sound like a product a couple of rungs up the ladder, then you can have it all.  If this is interesting, I'll be happy to share some insights into our successes with "mainstream" audio gear.  Not trying to drum up business here.  We keep pretty busy and you can have this done locally.  Just didn't want you to place the Denon in a Garage Sale or demote it to a secondary system if a performance improvement would keep it center stage.

An outboard phono stage (with decent interconnects) is recommended with this.  If you like your DM630's there are some do-it-yourself mods you can perform as well.  The goal here is not to fundamentally change the voicing the the B&Ws but to just get things out of the way that crush detail, dynamics, and imaging.

Best of luck in your pursuits.

correction, that listing is from Eugene in Canada, not Vlad. I wrote him, the gasket in that arm looks perfect. Verify proper double boxing with Eugene if you order from him.

Vlad's current listings 

https://www.canuckaudiomart.com/userads.php?user_id=10089

you could start with a great arm with VTA on the Fly

this one has the base plate for a technics plinth (scroll down, see 'other listing)

then you need to find a TT to put it on.