Integrated suggestions

Funny you should mention Octave as I currently own one of their amps & have owned 2 others in the past! As I'm familiar with the performance of this amp I think a regression within the line would be more noticeable than other manufacturers...if that makes sense!

Ha.  I was a quantitative analyst/market strategist on Wall Street and did quite a bit of multiple regression analysis so yes, it makes perfect sense to me.  Just make sure you account for autocorrelation and heteroscedasticity 😉.  Seriously though, what Octave amps have you had and what do you think of them, and what did you end up replacing them with and why?  They’ve always been high on my radar so I’m very interested in your thoughts, impressions, and comparisons if you’re willing to share.

be prepared to get not nearly what you think your equipment is worth.

I am going to 1+ the Musical Fidelity recommendation. I have the M6500i and it is fantastic. It drives my speakers with such ease they sound like different speakers. MF really is about refinement and ease of effort. If you can get your hands on a dual mono design like mine, go for it.

My second choice would be a tube integrated from Line Magnetic. They offer a very good product for the money and undercut many US integrated tube companies.

I have a LM Audio as well.

Gato Amp 150 , and Belles Aria Signature

I'd certainly be tempted by the Willsenton R800i, which would leave you with $1000-2000 to upgrade the tubes to your liking.

Also, maybe you could get a deal on a Synthesis A40.Virtus. I have its big brother the A100, which I prefer to any amp I've ever owned.

Good luck finding something you will enjoy for a long time.