Excellent Solid State or Hybrid Monoblocks Recommendations

I second Pathos hybrid InPol design. My Heritage MKii is integrated and is my endgame.  Rock solid bass and air mids and highs. I’d assume their hybrid separates are of equal quality.  Worth a listen. Especially sublime with my Tannoy Kensingtons. Also enjoyed my BHK300’s a few years back with the BHK pre.  I only let them go as I needed to downsize boxes and so went integrated.  Good luck.  Many good products out there.   

Pathos is nice, Canor too.

@jaymark I'm just dipping into the German tubes since there's such a price premium and the market is flooded with fakes, but the ones I've tried have sounded great.  Have you checked out Brent Jesse's stock?  For ~$100 more for the quad, he's got the Siemens Cca, which is supposed to be the top of the line Siemens tube.

My current favorite is Mullard's 6DJ8/ECC88.  If you enjoy acoustic performance, piano or vocals, they sound the closest to live music to me and very addictive.  There's a premium on the original Mullard branding, but generally can still find them for $100-150/pr for NOS and all sound very similar.  You can find some of the rebrands for under $100/pr. with Brent Jesse selling a top end E188CC/7308 version for $375/pr..  I've noticed I need to turn up the volume a bit more to get good solid bass with Mullards, but its mid-range is what sets it apart from other tubes. 

Tungsrams are on the soft side and opposite of the stock tubes that come with the BHKs.  They're worth having as a spare set, but (in my systems) make voices seem further back and bass response a bit too soft.  Not as soft as the Valvo E88CC I have, but definitely on the soft end.  As a cheap Russian NOS, the 7308/E188CC National branded Vokshod sounds very close to the big name European NOS and not a bad tube.

I'd highly suggest checking out Amperex 6DJ8 A frames as a reference point.  They're such a well-balanced tube and have been very helpful with testing equipment changes and diagnosing issues.  NOS are easy to find under ~$70/pr. and sound great with livelier music, even at lower volumes.  Strong across the whole range with great imaging, just not a standout in any specific area. These may be a good starting point where you can make decide how you'd like to tweak the sound or what may sound best with your equipment.

Generally, I've tried 6922, 6DJ8, ECC88, 7308 and PCC189 and prefer the 6DJ8/7308.  These smalls tubes really don't get too hot and the red light in back will go out ~10 minutes after you shut off the main power switch, so it's safe to switch out with a gloved hand.  I also noticed the Acme fuses narrowed the gap between tubes and improved bass response with the softest sets, but just my experience.

Some 5years ago a then friend had a Pathos hybrid. It developed a problem and he went crazy trying to get it serviced in the US, and too expensive to send back to Italy. Hopefully US support has been resolved

@jaymark Sorry to go off topic but how do you get in touch with Doug Jessie at ASi Teknology?