Teaming Audio Research pre with Parasound JC5??

Just because John Curl designed the amp, Parasound uses good parts but does hold Mr. Curl back.

In terms of power amplifiers that can easily drive a set of B&W for roughly the same price, you can get a Coda .8 which is a 250 wattt amp with the first 12 watts being in pure Class A. 

THe Coda .8 has a massive 3kv transformer, and is built by Doug Dale who was with Nelson Pass at Threshold. 

Many people consider the Coda amplifiers to be sonically similar to the Pass with a little bit less emphasis in the midrange, so similar flavor with a slighly more neutral platatte.

The .8 was rave reviewed in Home Theater and they compared the amp to the Parasound and a pair of $14k Pass Mono ampliifers. 

If you need power with finesse, a huge soundstage, from a company who has been in business for over 20 years with a cult following throught the world you should look at a Coda. .8 just magnificient.

https://hometheaterreview.com/coda-technologies-continuum-no-8-stereo-amplifier/

Dave and Troy
Audio Doctor NJ Parasound and Coda dealers

(((If you need power with finesse, a huge soundstage, from a company who has been in business for over 20 years with a cult following throught the world you should look at a Coda. .8 just magnificient.)))
 Dave and TroyI disagree with your well-intended recommendation
His Ref six would really shine with a partnering amp with an input impedance of 100 K for best cohesive operation.
 The pre-owned ARC Ref 150s power amp has an ideal input impedance a great power supply fantastic performance and will sing well ginellis1 with your Ref 6 / Bower&Wilkins speakers.
 Best JohnnyR

The JC5 is a very good amp, but the CODA is in another league. 
The 803D is easy to drive for any ARC tube amp, just use the 8 ohm tap and the results will be magical.

Sorry to disagree John, the older ARC amps tend to spotlight the top end a bit which may lead to a bit of additonal brightness with the 803D.

Also the Ref 150 amps even used are way more expensive and then you have the issues of tube life, heat, and lack of bass control.

The ARC amps are very good amplifiers, the combination of a tube preamp coupled with a powerful solid state amplifier has been the best of both world's for many years, you get the superior bass control and dynamics of the solid state amplifier, lack of noise, and zero cost to replace tubes, furthermore, you get piece of mind without having the failures of a big tube amplifier.

Dave and Troy
Audio Doctor NJ Coda dealers

According to a seller on US Audio Mart there is now a .8 version 2 with even more power, although I do not see it on the Coda website.  He says "This is the V2 version with 250W/ch into 8 ohm,500W/ch into 4 ohms with the first 12 watts being pure class A."