Best Options In A Balanced Preamp Under $1500.00?

I'm in the process of helping a friend who is a music aficionado, musician and budding audiophile build his first system. As a relatively young guy, his budget is somewhat limited. He will be using a pair of Monarchy SM-70 Pro monoblocks for amplification and now needs a balanced preamp, as those amps truly need a balanced signal for optimum sound performance.

If he had a bit more to spend, I could advise him, but in this particular range of price, I'm not as well versed. What would you recommend in a used balanced preamp as his best option(s)? I say used, because I am not aware of anything in that price range that can be had new, and also to maximize his investment. Any assistance would be greatly appreciated. Thanks in advance.
Keep your eye out for a used BAT VK-5i or VK-3i.
Wait on a used W4S STP-SE. A lot of pre for the doe...
There is a used Musical Fidelity M6PRE for sale on Agon right now priced at $1500. M6PRE an excellent preamp for that money.
The PS Audio PCA2 is another you could add to the list. There's one listed here now but the price is a good 40% too high IMO.
I owned one for a while, nice smooth operation and neutral sound.