Decisions, decisions, decisions

"I have a Marantz integrated at 50W"

Get rid of that first. A nice Musical Fidelity integrated would work nicely.

That's not what I'm asking about but thanks. 

I have had Vandersteen 2ce SigII speakers for many years now. They are truly nice sounding. Laid back and natural, organic. Great with jazz or blues. Musical to be sure. They like power, but to be honest 50 watts would drive them fine. I would agree that a dedicated amp would give better results. These speakers will take you up a level in sound as you better your electronics. Also can pair well with subs. I think these speakers are sleepers, because they have been in production a long time.

What is the model number of the integrated? If it is typical newer mass produced Marantz then the speakers will be severely limited by the amp to the point of the lack of capacitance, small transformer size and so on pretty much needed for the speakers you are asking about will equal some pretty constrained performance. 

The Van's are an excellent choice! Try them. Hope you have a friend that can bring over something that will open them up so you can hear what can happen as a comparison. I'm willing to bet a Pass Labs X250.5 would rot your mind on the Van's placed side by side with the Marantz, not running wide open, just cruising at say 20w/ch

Get the Vanders.  They will sound great with what you have and next year you can shop used for an amp that will take them to the next level.  It takes years to build the system up so no rush.  If you buy based what is best for your weakest link currently in your system, you system never progresses beyond that weakest link level.    

You are looking at two great speakers, both of which would benefit from sn amp.upgrade. You have an Adcom GFA-5400 - that's a Nelson Pass designed 100W MOSFET that was a great amp new and is still competitive today. I'm pretty sure your Marantz has pre outs, so you're one set of interconnects away from a very workable amp setup. Now, let me toss out another speaker you should consider.  A Stereophile Class A rated full-range system, the only one under $10,000 pr. The Monitor Audio Silver 300-7s. I have a lot of respect for both the 2ce and the Sonnettos, but the MAs are simply a better value. Range, dynamics, transparecy, they are the complete package. If you're not a Stereophile fan, then consider these: the 2021-2022 EISA Award for Best Product in the Floorstanding Loudspeakers category, the 2021-2022 Hi-Fi News Best Value Floorstanding Speaker award, and the 2021-2022 Hi-Fi News Outstanding Product award. Yeah, they're that good. And with 90dB + sensitivity, your Adcom is plenty of power. At $3250 per pair $1750 less than the Sonetto, that leaves enough to start to consider what your next step might be. 

I presume you’re talking about the Nelson Pass designed Adcom 545 II.

It’s funny- I recently got the Magnepan LRS+ for a bedroom 2,1 system and assumed I’d have to get a new amp.

Much to my surprise, my old Adcom 545II drives the Maggies so well I don’t know what more I could want.

I have seen Vandy 3 and 4 used and priced in your budget.  However, a more efficient speaker allows you to keep your amp.amp

leaves 

Consider the Sonus Faber Sonetto G2 3. At $4500 you avoid the cost of a quality stand and even a subwoofer might not be needed. As for electronics a used Norma IPA-140B will give you liquidity/low noise floor and great vocal reproduction. The only caveat is you need a high quality source and cables.

bipod72, you are getting lots of good advice & guidance here, so far.  Generally speaking, your Marantz 50 watter is a fine amp but really doesn't have the juice (i.e.  current) to make anything other than moderately priced 8 Ohm nominal load speakers sing.  As such, if you're dead set on keeping that amp in this game, the Vandersteen would be a better match, comparatively speaking.  However, at 86 dB, 1 meter with 2.83 volts input and 7 Ohms nominal impedance, your Marantz is still not a great match for them, either.  You'd be better off, fidelity-wise, with the Monitor Audio Silver that panzwagn is suggesting and better off, still, bypassing your Marantz with that Adcom, providing the Adcom is still in good shape.

I've never done any serious seat-time with a Marantz 50 watter but have done so with the Adcom, many years ago.  Much more recently (i.e. about 3 years ago), I did a considerable amount of serious seat-time with the previous version of the MA Silver 300 and the Vandersteen 2 when I was in the hunt for a speaker upgrade for my two-channel system.  My ears liked both the MA and the Vandersteen.  However, this involved using at least twice the juice of your Marantz.  I didn't end up buying either one, but my ears definitely preferred the MA, comparatively.  Those are simply amazing, at their price point and beyond!  I haven't heard their newer upgraded version, but all the reviews I've read agree they are a tad better than their predecessors.

Good Luck!   

OP get the speakers you prefer.Do it on your own choosing. You can’t go wrong with Vandy and SF. Keep us update to see which speaker you choose.Dont disappear like others.

Thanks everyone for the input. I may take another look at the Monitor Audios. The visual acceptance of the speakers by the wife is another factor I have to consider until I'm able to build a dedicated listening room. That being said, I'm not in the position to drop more than $4k on speakers at the moment. 

My planned upgrade path is as follows:

1. Upgrade my speakers first. Almost anything I upgrade to will sound far better and will make my current set-up sound much better I believe. 

2. My Marantz currently has a pre-out for a separate amp. The Adcom is fine for its age and while I plan to recap it this Fall, I'm leaning towards getting a better-quality amp anyway but nothing exotic. I still have kids to raise!

3. I'll keep the Marantz/amp set-up for a while and then decide if I ditch both for a higher-end integrated or a better pre-amp/amp setup. But I would like to land on a pair of speakers that I can keep for some time.

I'll keep you posted on my decision. I'm hoping to upgrade later this year unless I stumble upon a deal I can't refuse before then. 

maybe https://speakerchoices.com/

for 4K you have a lot of choices. 

I would determine it by room size and the need for bass

I agree with your approach, the speaker upgrade will usually provide the biggest sonic upgrade. Dub and Funk can be quite bass heavy, which is where most of the power demands come from. You don't mention listening levels, but if you start to push it with bass heavy material this is where I would expect the Marantz to start running out of juice. If you keep this in mind, and let your ears be your guide, I think you can enjoy a significant upgrade in sound with new speakers and your current amp, and upgrade power as finances allow. Good luck!

I fully agree with your approach! Go as big as you can in the speakers. As a Vandersteen guy and as someone that used to own model IIs I'd fully support a pair of those. What I will say is you need enough space in the room to get them a few feet from the wall. The good news is they're very shallow speakers so it's not hard to get that front end away from the wall. If you do get model IIs definitely get the stands. I agree that it's likely that the marantz will probably do fine driving them, the adcom even better. But what I'll add is that you'll have significant room to grow. The speakers will keep getting better as you improve your electronics. I think the other benefit of a full range speaker over stand mount plus subwoofer is that the crossover is already integrated. It's much harder to integrate a sub than most folks think. 

You don't mention listening levels, but if you start to push it with bass heavy material this is where I would expect the Marantz to start running out of juice.

I rarely get above 55db during normal listening sessions. 65-70db if I'm jamming out with no one at home to complain about it being too loud.  But that listening level is also determined by the limits of my current speakers!

The speakers will keep getting better as you improve your electronics. I think the other benefit of a full range speaker over stand mount plus subwoofer is that the crossover is already integrated. It's much harder to integrate a sub than most folks think. 

This is my goal. I want to get a pair of speakers I can grow into.  I'm curious if you think the newer subs that have integrated DSP software, SVS for example, make it easier to dial in a sub? 

I don't think it's that hard to integrate a sub. It only took me 3 months 

@grislybutter LOL....that sounds like an enjoyable process for any hi-fi hobbist. Getting to tinker and dial everything in until it's "just right" is what this is all about!

If you are considering Vandersteen IIs, you should really consider used Treos CT or Non-CT. Mine are beautiful, the highs are extended, and the lows are a pleasant surprise. My prior speakers in this system were Vandersteen 2CIs.    

If it were me, (and admittedly I am not familiar with all the different upgrades of Vandersteen 2CI, 2CE, etc), I would look to upgrade both electronics and speakers and buy used as you can save quite a bundle on used gear.  The Adcom GFA2 is an old early-mid 80’s amp that may need recapping?

With a $4K budget, you could easily get a great amp, preamp, and speakers, solid state or tube.  There are lots of choices that will simply blow away an old Adcom GFA2 and 50 watt Marantz integrated.  
 

I recently saw a PS Audio 200C that is a Giantkiller of an amp.  B&K EX442 or 442 Sonata is another Giantkiller of a map.  Lots of possibilities here.  

Just checked quickly on US Audiomart and for about $1000-1200 you could get:

1.  A Tandberg stack - amp & preamp;

2.  Aragon 2004 & 24K preamp;

3.  Muse 100 amp & Morrison Elad preamp;

4.  B&K M200 monos, Threshold CAS2 or Monarchy SM70 class A monos

5.  Marsh amp and preamp

All of these would be significant upgrades from your Adcom amp.  Lots of really good choices in the $500-800 range for used amps & preamps

I know OP didn’t like Russ69’s suggestion and I can see why. However, that’s really good advice IMO. 

@bipod72 I had Vandersteen 2CE signature IIs for a number of years before moving into a smaller home, where the listening room simply would not accommodate them. I auditioned a boatload of stand mounted speakers at that time. One of my favorites were the SFs. But, in the end, I chose the reference 3A de Capo speakers with the matching stands. The primary reason I made that choice is that the design shares elements of Richard Vandersteen‘s design of the 2CE’s and the sound resembles the Vandersteens. They use proprietary drivers and have no crossover circuitry; there is only wiring to the woofer and a single filter between the amp and the tweeter. I’ve been listening to them for eight years, and remain enamored of the sound. If you prefer the Vandersteen sound, I encourage you to consider them. They are well within your budget, particularly if you can find a used pair.

Thanks again everyone for the advice. I've a lot to consider as I forge my upgrade path especially with regards to additional speaker recommendations and pre-amp/amp options as well. 

@bipod72

Your choice of possible speakers is right on. Other options listed here are great as well.

I approach audio from a "bang for the buck" perspective as well as "risk factor(s)." It appears that the "little" Marantz is going to be part of your life for a while longer. The amp would definitely benefit from power delivery upgrades, starting at the wall socket and working its way to the power cord on the amp. You don’t need to go crazy with this. Things in the "$100 range" can make a notable improvement. When added together can result in (very) significant sonic improvements. Along this line, I would take a good look at your power conditioner/surge protector. A good test is to plug the components directly into the wall. If they sound better, then I’d be looking for something different in power distribution. I’m expecting some push back from those who are not fans of the items mentioned here. This is where the "low risk" element comes into play. If you can borrow these items for home audition (not so easy on wall outlet) you can listen at your leisure and make informed decisions. If they don’t put a smile on your face, then you can return them. (There may be more music in the Marantz than you realize?)

There’s more good news here. These items mentioned are "transportable." When you get your "forever amplifier" they will help the sonics of the newer/better amp as well.

Good luck.

Both very good. Apples/oranges. You get to choose.

A beefier good quality amp can always only help. 

When I was shopping amps for my speakers I really didn't start to hear a difference until I stepped up to a Krell KAV 300il. I already had a B&K 4420 and multiple 150 wpc amps from virtually every 'mid level'  Acurus, Sunfire, Nak, Nad, the list goes on and tbh I think the only time I heard a difference was when musical peaks drove the amps to clipping.

I never 'got' the Vandy sound, but always see their room packed at Axpona and appreciate they're doing something very right to have built such a large, loyal fan base. If I have the choice I'll always buy used and less than 10 years old speakers b4 paying anywhere close to retail. I'd likely wait until a pair of SF came up used.