"Good tube Integrated Amps"

I left a $10k CJ combo for a demo PL Prologue Premium Integrated and never looked back.  Running stock EL34s to Harbeth Compact 7ES-3s.  Now I can relax and listen to albums the whole way through. 

What speaker????????

Primaluna HP Integrated all the way.  

Ars Sonum Filarmonia. Very musical. I use it with Merlins and the pairing is very special. Well within your price range on the used market. 

Have you considered a hybrid ? My friend is using a  Vincent Audio SSV-237 and it is stellar.
Operates in class A for the first 10 watts , 150wpc -8ohm / 250wpc-4ohm .Sells in Canada 
for around $2500.Many great reviews .

Just saw that there is a PrimaLuna Dialogue Premium HP in the sale section here that's in your budget.

Very happy with a Jolida JD302 CRC I got as a demo for 1/4 of what you're talking about.  Of course I like EL34s and there are so many around to experiment with these days.

I have had a few system tryouts and ended with the Primaluna Dialogue Premium with KT-88 and NOS Philips 12AU7 as pre matched with Rotel RCD-1072 driving the ProAc Tablette 2000 Signatures. For the money that I spent on this current system, I could not be happier. What I like of this system is the real natural sound with rich lush midrange and 3-D like soundstage. 

Add another to the very happy with the Rogue Audio Cronus Magnum II list. Great sound, great looking, American Made to boot. 

I agree with zimwig, Primaluna Dialogue Premium with KT120's, Upscale Audio

Primaluna Dialogue Premium with KT-120’s. Auto biasing. Can’t beat it for the price.

I have a Rogue Audio Pharaoh that is a very nice amp. I may be looking for more power. Feel free to make an offer 

A good used Jadis DA60

+1 For Rogue Cronus Magnum II.  I needed more power than my Cary CAD-300s deliver for my Harbeth SLH5+s and am very happy with the sound.  KT-120s!  I don't do so much vinyl anymore, and the phono stage gives me everything I want.

I almost got Cronus magnum 2 but kept seeing so many on secondary market figured it wasn't a great sign. I wanted Manley, but too expensive, same with the Cary sli-80...I ended up going for primaluna Classic, which is a great sturdy amp that holds its excellent value, haven't seen those on secondary market really...I do wonder what more watts would sound like sometimes, but look forward to upgrading to the KT-88s...the primaluna supposedly lasts longer, putting less stress on the tubes...

PM me if you decide to sell your VSI60.  I had one a few years back and really regret getting rid of it......

How much power do you need.   Eastern Electric makes very nice products for the money.  They are built like tanks and some have many features  for tweaking the sound like my M520 25w/ch but can drive small Maggie's in a small room no problem .   Bill at Morningstar audio is excellent to deal with. 

A must listen is the Audio Research VSi60 or VSi75.
They punch well above their weight, and have the solid ARC house sound.
I might be selling mine (VSi60) in the coming weeks, but it would only be to go to Audio Research separates. But I’m gonna let it take a swing at pushing my Wilson Audio Sashas (in bound) when the arrive.

pear audio blue Classic intergrated at 4K ,

Hi there
for 5k you can get a used audio note meishu (the sweet spot in the audio note UK lineup). It is a very highly regarded integrated amp. I've had mine for 20 years and i get everything i want out if it in a 350 square foot room and 93db speakers. You will need fairly efficient speakers unless the room is small. 

Line Magnetic Audio 218ia SET amp. Very nice sound. I have the 216ia and had the 218ia for a short time. It was very sweet sounding.

PrimaLuna Dialogue Premium HP is right around that price range.  Read the reviews.

I’d add the Ayon Scorpio to your audition list.

Another shout out for the Manley Stingray II. I also have one; it's a keeper.

I second the recommendation for the Rogue audio Cronus Magnum 2. Full function with remote and moving magnet phono stage great output and fantastic sound

I listened to a couple Primaluna integrateds and was searching for a used one and came across a Manley Labs Stingray II. I preferred the sound and ended up buying it about a month ago. So far I am very pleased with the sound - rich, warm with some nice low end punch. As a bonus, the American made amp features a unique industrial design that is pretty showstopping. All my friends, even those who don't give a hoot about stereo gear, have commented on it. 

Bottom line, there are a lot of great options under your price point. You'll have fun discovering the options. Good luck!

I'll second wolf_garcia's and other's comments about the Maryland-based Jolida.  Had a Jolida 502B for a decade.  My intro to tubes.  Good value for the money.  The factory upgrade for it was another high value bargain.  It responded readily to tube rolling.  It's well within your budget.  I liked the fact that biasing was manual (and easy to do, I might add).  Only reason I stopped using it was I needed more power for some lower efficiency speakers. Good luck in your search.  

+1 Jolida! I've always liked their gear. My FX10 was such fun in a desktop office system. Always punched above its weight to be cliched about it. Very inexpensive, yet truly good sound and design. I always thought Jolida (MD) should have upgraded that model slightly, charged a few hundred more bucks for an extra input, better volume control...many folks would wonder...why pay more??? Their other models are stellar. I don't own those but have heard them in enough different folks systems to know how good they are.

I’ve had a "factory upgraded" Jolida 502p for years and am so impressed with its quiet and powerful presentation of tube slam and refinement I that I don’t hesitate to recommend this stuff…that 3502 looks cool, and hey, it’s still much less expensive than any comparable amp from anybody else. There are very few new reviews of Jolida amps, and simply zero ads in appropriate magazines…not sure if there’s a connection there, but modern Jolida (the MD guys) gear deserves some props for design and execution. Having personally compared my amp (a few times in my own listening space) to similar amps costing much more money from frequently reviewed manufacturers, I’ve felt the Jolida is simply better sounding, or at least every bit as musical as the much more precious stuff.

Decware tori , mini tori

Here ya go ! Made in USA for $2500.
http://www.rogueaudio.com/Products_Cronus_Magnum.htm

Cary SLI-80 F1 edition.  Versatile and very musical. Readily available on the used market.  Has passed the test of time and manufacture and supported here in the USA.

I am thoroughly enjoying my Jolida 3502, which can be had for less than half of your budget of $4000. It is versatile, dynamic, and sounds great.

You might also check out the PrimaLuna line, which a lot of people like.