Integrated Amps

Marantz makes some pretty good integrateds, better than many of the non-japanese designs simply due to Marantz (like Yamaha, Sony, Luxman and Denon) knowing how to design a quiet circuit. I haven’t heard the Billie. It gets good reviews but I’ve seen quite a few of the mkII version on the pre-owned market already—unusual for what I imagine is a low-volume product. 
 

For integrateds, I haven’t encountered any that outperform the Yamaha A-S2200 or A-S2100 for their street price. They combine the good traits of tubes and solid state better than any of the hybrid tube/SS products I’ve used/owned. Usually with the latter, instead of the “best of both worlds,” you instead get the worst of both. 

The Audio Research i50 is a fantastic integrated. They have a DAC and Phono stage card upgrade as well. You can find them on HiFiShark for under 4K.  That's a LOT of amp for not much money.  I think they sound fantastic- typical ARC sound- tube warmth with analytical precision, 

https://www.hifishark.com/search?q=audio+research+i+50

Pass Labs INT-60

Class A to 30 Watts

If you are thinking of upgrading your speakers the advice of upgrading those first, prior to the integrated is really good advice.  Synergy as noted in several responses is so important between gear, especially speakers and amp.  It’s tempting if you are going with an Integrated to get an Integrated with everything, DAC, Phono Stage, Headphone Amp, the list goes on.  Really good advice I got from others is to focus on what sounds best in an integrated, getting the best pre / amp combo.  The Phono Stage, DAC are items you can add into the mix and you’re likely to get better performance and flexibility by going that route.  If you have your heart set on an Integrated, one box that has everything and does it all well, the NAD mentioned in this thread is an unbelievable value, great performer.  The streamer / DAC built in is extremely well done, has room correction, really does it all and is about as future proof as you could hope for.  
 

Integrated Amps I’d add to your list: 

Parasound HINT 6 - incredible value, bang for the buck, SS and can drive almost any speaker

Coda CSiB - Coda is probably the most underrated high end Hifi manufacture out there.  The engineering, parts used and overall build quality are second to none, it’s not cheap but you’ll pay many multiples above there gear just to match it, it’s a no frills integrated, can drive pretty much any speaker. 

Krell 300i - might be the most magical Integrated I have heard, something about the combo of power, control but also a liquidity, tubelike quality without any of the draw backs of tubes.  

PrimaLuna Evo400 - All Tube Integrated built like a tank, no frills. 

Linear Tube Audio - several Integrated Amps - like Coda, incredible build quality for the price with top notch engineering, if you want Tubes, really hard to beat and incredible value relative but not cheap. 

McIntosh is a polarizing brand but they make solid state, hybrid and Tube Integrated Amps, hold their value like no other brand. 
 

Hifi Rose RA180 integrated - highly reviewed, very well done Class AD amp, will drive almost any speaker

Niam - make several integrated amps that would cover all your bases, well thought out DAC/Streamer built in

Hegel - 3 different models, often one of the most highly recommended by those who own one.  Very well done streamer/DAC combos, if you add a separate streamer / DAC can raise the performance which is already really, really good.

I’d buy used, buying Hifi gear is like buying a car, it depreciates 30-60 % as soon as you open the box, you can really stretch your dollar going used.  Good Luck

I am quite impressed with the Soulnote A2.  I see it occasionally only used for under 5k.  It is SS but has a wonderful warm but resolving sound.  From your list, and other recommendations, I can only say it is much nicer than the PS Strata, or NAD, which I have owned or heard.  Very high quality build, and completely transformed a second system.  I combine this with an Auralic Altair G1.1, a value oriented piece, and it sounds very good.  There are many fine integrateds for sure.  Keeping the DAC separate is very flexible going forward.  The Soulnote developer left Marantz to create better sounding components, and not have his hands tied by corporate ownership.

I just want to say the new NAD class d amps are very clean but there is no warmth at all. A friend just tried out the preamp / amp stack of the master’s series. Very clean but NO WARMTH. I liked it on Maggies, my friend did not. For what it’s worth.

I would be wary of purchasing any integrated amplifier with a built in DAC. As enticing as that may sound, in most cases the built in DAC is inferior to even an inexpensive stand alone one.  More importantly, the resale value of the amp will plummet as soon as the manufacturer introduces a similar model with a new and improved digital section.  And we know how much that hurts when you inevitably decide to upgrade again.  We’re audiophiles!  I think the next big thing in DACs will be a near universal adoption of USB C inputs.  A couple manufacturers offer an internal DAC as an option on a plugin circuit board that, in theory, can be replaced with a more up to date board, which seems like an excellent way to stave off obsolescence in the fast moving world of digital.  I know that NAD, McIntosh and Accuphase do this, and hopefully other manufacturers do, too. Best wishes!

I resurrected my system five years ago by purchasing a Yamaha A-S3000 integrated amp. It was a huge sonic improvement over the Yamaha A-1000 integrated I bought in 1985. It was easy to discern because I had the same speakers, Infinity RS-4b’s.

The sonic improvement was the start of a very deep rabbit hole for me. I upgraded speakers next with Magico A3’s. Then I listened to a Prima Luna integrated amp a buddy let me use. That led to buying a Dynaco PAS-3X tube preamplifier. I paired that with the A-S3000. The sonics were an improvement over the A-S3000 alone!

I’ve since upgraded the preamplifier, the power amplifiers twice with two pairs of mono blocks, added a separate phono preamplifier, upgraded the turntable, cartridge, cables, power cords and added room treatments, Soon the power conditioner will be next.

I’ve enjoyed the journey but I was naive as to what I was getting into when I upgraded to the A3’s in regards to what it would take to bring the sonic level of my rig up to what I heard in the demo. My advice is to proceed cautiously.

Obtaining synergy between components most likely will become very expensive. I also have another rig which uses the old RS-4b’s with a Scott A 436 integrated amp and McIntosh MR-55A tuner. I enjoy that system almost as much as the main rig when I listen to it!

I went from Marantz to Musical Fidelity m6si and have been happy.   Gave me more power and a familiar but better sound.  I took my speakers to a few whops and listened to several to make sure they matched up.  If new speakers are on the horizon, agree with others to match them.  

Also, I use my old Marantz, repaired, to drive outdoor speakers.  Might work for headphones too depending on your situation. 

Class D look for the gato dia 400s and a very good dac.

@bipod72  as ​​​@ghdprentice noted, whilst appreciating your primary interest in the Billie, looking at the costs of others you noted such as the PS Audio one for potential consideration might be the NAD C399. It has a just about everything uprated from the C3050. Which was why I bought one for my Daughter and Son-in-law for a Wedding gift and seems to tick a lot of your boxes, apart from the tube point of the billie, but perhaps a tube stage later if you use/go MC could give options.

It has 180W/ch continuous (250 peak) hypex so power wise your speaker upgrade is well catered for and the Hypex modules stand up relatively well in my Trinnov Amps for musicality when I have tried them against my Vitus SS103.  The NAD built in phono stage has had some highly complementary reviews as noted at https://www.theabsolutesound.com/articles/nad-c399-hybrid-digital-dac-amplifier/ stating quietest phono stages he had heard below a $29k separate and better than he had heard integrated outside his Mcintosh C53. But an AV forums review was a bit less enthusiastic on the stage, but didn't give the amp less than 9/10 in any category.

As it was 'boxed for present' and they live a 100 miles away I haven't listened to it alongside my Whest MC Ref's or Titan Pro II. But on their system Project X2, with both an Ortofon 2M blue and even more with an LVB 2M black it sounded very good, both with and without the option of built in Dirac, which is another bonus if you would consider / want room correction, there are two MDC module slots with the BLUOS-D that has the Dirac taking it from quoted $1999 for the amp with MM etc to $2598 with the module, but it can be added later.

If you are MC on the phono the review above was complementary of it with a quicksilver SUT. Personally I have not been able to find an SUT+MM into any of my pre's that get near a Whest 30 SE or above.  If you are or might go MC there are guys on here who could recommend SUT's.  But if vinyl is your prime source and you are/ will be going MC I personally would be considering MC Stages with a Whest on the audition list as I have put mine through a 25 year old Sony integrated that was designed for SACD and notwithstanding limited power the capability of that as a source shone through, but that is if you were considering a different path and others mileage will no doubt differ and as noted, you could go tube phono.  

The C399 has a built in headphone amp which I note you wanted. And my son-in-law reports the Apt-X Bluetooth (which I believe is 2 way) is certainly the best source he has heard into bluetooth headphones when he is outside.

So MM whilst stage could be the limiting factor, it is with a lot of integrated amps. But seems to meet enough of your requirements that a listen could be worthwhile.

I’ll offer my two cents on the Billie amp. I had the Mark II version for a couple of weeks to try it out. I was very impressed with the build quality, the design and the functionality of the user interface. I can’t comment on the built-in DAC or the Bluetooth as I did not use either of those functions. 
The sound quality I thought was very muscular with a clean mid range and good high-end extension. The bass was strong, but clean and very well-controlled. Overall, I was very impressed. However it wasn’t a good match with my high-efficiency speakers. I imagine that it would be a very good match for speakers that require a lot of drive such as panel speakers or those which with large heavy drivers that need a lot of control. 
The manufacturer took the return with no hassles and they were very easy to work with. I believe there’s a 30 or 60 day return. So it might be worth a shot.

If you’re planning to upgrade your speakers. I would do that first, then go shopping for an amp to support it. This will allow you to know the strengths and weaknesses of your system with the speakers… perhaps try some amps with your system. Best thing is to start upgrade cycle with new speakers.

the British Audiophile is one of three channels I watch, he is very honest and lacks any BS-ing skills, luckily

@soix I'm looking for more power than the 50W the Marantz has, as I plan to upgrade my speakers later this Fall. Key features for me are a good integrated phono stage, headphone amp, digital inputs, 100wpc, good sound quality, and a touch of warmth.

@grislybutter It was the British Audophile review that peaked my interest in the Heaven 11. But it's newness gives me a bit of pause but considering they're offering a 5yr warranty at least they're standing behind the product. Considering the Mk2 is sold out, I suspect they'll be releasing a Mk3 but who knows when that might be. 

The pause I have on Music Fidelity is that neither of the models I"m looking at have a headphone amp. I consider that to be a basic feature and I'm not really interested in buying a separate headphone amp and bypass just to listen to my cans at night.

The Rogue seems intriguing. I'm leaning towards the PS Audio but I'm not pulling the trigger on anything until after the first of the year so I have time to do a little more research. 

I have seen the Billie before but have not read any convincing reviews. Good looking amps for sure.

actually I will check out this

https://www.youtube.com/watch?v=GLix5NZsBoc

There is a whole world of great sound quality out there to explore. It can be intimidating and pretty easy to make a wrong first moves.

First the landscape. Moving out of Marantz is a great first step. There are a couple long term reliable… built to sound great budget brands: NAD and Rotel. These are a step out of consumer offering. Reliable, good sounding, and built like tanks, lots of reviews, long histories. Then there is Schiit… yes really. This is a great budget “high end” entry brand. Also, highly reviewed and excellent value for the money. Alternatively there are many many boutique brands like the one you are looking at. They can be great value for the money. There is risks of good performance of some characteristics and not so much in others, the brand might not be there in a few years, reliability could be an issue. I am not saying any of these are true with Heaven, I don’t know. Any way consider NAD, Rotel, and Schiit, as a first step into higher end electronics. On the other hand Heaven could be a great choice.

Recently spent some time with a couple “Advance Paris” integrateds that sounded impressive.  Tube pre section and many options from built in phono, DAC, CD player, blue tooth, USB stick, ect that can be opted for depending on the model.  Cost was super competitive. 

I wouldn’t add a separate power amp — the preamp is too important so I’d just get another integrated.  What specific improvements are you looking for?

Get one of the incredible Hegel integrated amps!!!

You would like the Musical Fidelity.. I also like my Rogue Sphinx V3 hybrid. Upgraded to Gold Lyon tubes, a very good combination.