Amp for LS50

@b_limo It sounds like your brother's Peachtree is not the new stuff made in Canada. They basically restarted the company with N. American manufacturing and new designer. They ditched the tubes for lower noise floor.

The NOVA line and LS50 are a very good match. I had a Benchmark DAC3 + AHB2 hooked up to the LS50 and it was a bit better than the NOVA 150 but it also cost more than 2x the price of the NOVA 150. I sold the Benchmarks and kept the NOVA and LS50. 

Peachtree give you a 30 day trial so, if you are inclined, do a little bit more research on this combo. You really don't have much to lose. The new NOVA 500 has a new DAC and newer preamp section.

https://darko.audio/2017/01/dancing-with-the-big-boys-the-powerfully-persuasive-peachtree-nova300/

Here is my next Peachtree upgrade.
https://www.peachtreeaudio.com/nova500-amplifier-with-dac.html

The Peach tree is okay but I was not satisfied with the model I heard... I don’t think $1k is enough of a budget for an amp to pair with the kefs unless you search hard for a decent ab unit in the used market. Unlike a lot of $1k speakers the kefs will scale with better electronics. I had a $15k digital front end class a pass Labs with kefs and it was sublime and a huge upgrade over the anthem 225i I had before. 

I highly recommend the Kinki Studio ex-m1 for your kefs! Within your budget too if you can stretch $500 as it is both a preamp and amplifier. 

Good luck 

Let me be clear, I wasn't necessarily endorsing the Mivera amp above amps by Nord or Apollon that also use the AS1200 module. There are many options out there using ICE and HYPEX modules in amps. Apollon, Nord & Wyred4sound (used) should all be available in your price range. d2girls is correct that the KEFs will reward you with better electronics, no doubt about it. 

Wow, That Kinki Studio exm1 looks to be insane...  I read Nonoises review (in addition to some online info / reviews).  Looks to be quite the integrated amp for $2200.  I’m not sure if I have that in my budget right now though, unfortunately.  We’ll see...

Now all I need is about 10 more good choices to really confuse me, hahaha.  

I had my LS50s running off my Ayre VX-5/20 while I was awaiting my new floorstanders to be shipped.  I was amazed at how well they performed with high quality power.  I have attempted to find a less powerful amp to run them in a second system and realize after some trials they really shine with quality watts.  You may want to acquire the amp upgrade first and enjoy what the LS50s can do while you are awaiting your speaker upgrade.