Amp Upgrade time, $6000 budget, used or new.

Wow, 6K, there’s an ocean of amps out there!

If it were me, I would seriously look at the Sanders Magtech ,
will drive ANYTHING, and is reliable, is class A/AB, lifetime warranty........DID I MENTION LIFETIME WARRANTY.

Roger Sanders is a genius, and the Magtech is ALL the amp you will ever need!!”!

plus a 30 day free trial.

www.sanderssound.com.
Seriously look into it. You will,Not be disappointed!!!

enjoy.

the Magtech is made just for magnepan and electrostatic speakers which need gobs of current.

 If I were you I would look into the Sanders Magtech!!”!

their amazing,and stable to 1Ohm or less.

Buy a used Mccormack dna-1 or dna-.5 and have SMC audio (Steve McCormack) upgrade it.  I had him do a dna-.5 and ended up selling my parasound jc-1 monoblocks.  Total cost (including purchase if the dna-.5) of about $3k and competes with amps much more expensive

Pass Labs, best you can find for the $. Decent resale too.

If you care about soundstage you may consider VTL MB450 used.

https://www.audiogon.com/listings/lisa2afe-vtl-mb450-signature-monoblock-amps-tube

https://www.stereophile.com/content/vtl-mb-450-series-iii-signature-monoblock-power-amplifier-page-2

I had been using only tube power amp except driving subwoofer for last 20 years.

I had been happy with Line Magnetic 508 for last 3 years but it may not have enough power to drive your speaker.

There’s a pair of McCormack DNA1 monoblocks with Steve’s Ultra Platinum upgrades for $3500 on US AudioMart.  Pretty darn close to perfect IMHO.