Power cord to add ease and tame treble.

Try just adding a single Wolff Carbon Source AC cord or Grover/Wolff Empress IC...... very substantial reduction of digital grain/glare, trail periods available. Both cables sold here at Audiogon.

I see you don't have power conditioner, this can help give you smoothness you seek.......but also some can restrict dynamics so must choose carefully here, I like Audio Magic power conditioners but they are expensive.

A recent posting regarding speaker toe-in reminded me that an easy way to tame a hot treble is to use less toe. The apparent reason: a tweeter's response declines as you move off its direct axis. A freebie tweak! Try it and see.

Its quite a game isn't it?
After many ic and pc problems and yes I have gone the Cardas,JPS Labs,Blue Circle ,Audience route.I do believe cables make more of a difference than components, by quite a large margin.
Try line conditioning and some of the smaller cable guys like
Audio Magic ,and really worth a try "Z-squared" ,personal review soon.Very complete sound with their gear.FWIW
Peter D.

Glai,
I would try a master pc for virtual dynamics. Install on the your Ayres and listen to your system transform to another level. Good listening!!

Like a few have mentioned... A power cord is not going to solve your problems.

Here's part of what I think your problem is...Your preamp is not a good match for your amp. I believe Stereophile reviewed your preamp and the most useful part of those reviews are the measurements. Take a look and I think you'll find that your Pass amp does not have the optimal input impedance to mate with the Hovland.

Also, you may find that your JMlabs are not the right choice for your taste and room. The BE tweeter is an impressive piece of technology, but sometimes great individual parts don't make a great whole - just like combining a bunch of "recommended" components doesn't always make a great system.