Preamps

Is it a good match from a technical point considering impedance matching between the amplifier(Jeff Rowland 625 S2 and the Chord CPA 5000?

The Corus has a 60 Ohm output impedance and the CPA 5000 has 100 Ohm, they would be indistinguishable impedance wise into the 625's 40kOhm input impedance.

I’ve paired my Freya with an ARC REF75 amp and it sounded astonishing

+1 for the Shiit Freya, a 3 in 1 Swiss army knife with the best mechanical volume control you can get.
Has to be the bargain ($699) of the decade, embarrasses many $$$$$$K preamps, it’s got what’s needed under the hood that’s why.
Probably not dazzling enough for the "glitz queens" though.

As for the questionable coupling cap statement (above), the Schiit freya uses Wima coupling caps, so do many others. like this 8K euro Acoustics Arts from Germany that got raved about in 6 Moons
http://3.bp.blogspot.com/-dYJpNC7cRxQ/VI4GXO11ogI/AAAAAAAAwu8/tz9_JDR7cIA/s1600/accustic_arts_monoII...

https://6moons.com/audioreviews2/accusticarts/1.html

Cheers George

Does anyone know why Don Sachs can't add a balanced output on his SP 14?

Why is this such a difficult task?

Another unit to check @ at the top of your price range would be the Levinson No. 523 (the same as No. 526 but without the DAC module); it would also match impedance wise with the 625. 

https://www.marklevinson.com/productdetail/~/product/no523.html

https://www.stereophile.com/content/mark-levinson-no526-preamplifier