Amp Upgrade - 3k to 4k used?

Hi Folks:
I’m thinking of upgrading my amps and would value some advice. I currently have Blue Circle BC2 Monos. I’ve been really happy with them, but the upgrade bug is starting to bite again. I could spend about $3k to $4k on the used market. I’m particularly keen on tube amps (especially low powered SET), but not sure if my speakers would be efficient enough. I know my CD player is a little old too, but don’t think an upgrade here will get me a big bang for the buck. I’ll also consider upgrading IC and SC as well a little later on, but want really really good stuff (FIM or Valhalla likely). Another option may be to get a Shunyata Hydra. The rest of my system is:

Audio Physic Virgo II (89Db efficiency, I think)
Sonic Frontiers Line III – (but expecting delivery of Supratek Chardonnay in a month or so).
Nordost SPM IC & OTA Sakura IC
OTA Sakura Speaker Cable
3 Shunyata Sidewinder Power Cords, 2 YBA Diamond Power Cords, 1 pair of Bybee IC Filters, FIM outlets.

All advice and recommendations welcome. Thanks,
John- On the used market, don't forget about checking out a Cary 805b or c, and also the WAVAC 572. These SETs have power and sonics. I also like some of the OTLs, but they usually require a bit more "user involvement" in their care and feeding. Good luck.
WARNING! Philosophical Viewpoint Coming -

I have been on the upgrade path for 25 years and still can't get off BUT I recently put an early 1960s integrated
full function amplifier in my system for "fun" and "nostalgia". Guess what? It sounds quite fine - price $200 US. It will even let me listen to my moving coil equipped 'table ( not real loud). I will likely stay addicted to the upgrade bug but I could live with the "old integrated". Perhaps some of our current gear will become "classics" and be appreciated for what it is and what it can provide as enjoyment. Enjoy what you have; enjoy the MUSIC.
If I were you, I would find a pair of Pass Aleph 2's... There is a pair on Ebay right now for ~$2500...

You will never deal with tubes again... Same mids and highs, much better bass, and no hassles...

Just my $.02...

Good luck,

The Hydra will do wonders-it did for me anyway. Do you have dedicated outlets with iso grounds? That'll help to. I had a pair of Virgo II's for 3 years. A single BAT VK60 drove the heck out of them. However, I've heard running 2 in mono is even better. good luck...
John -

You might consider a pair of Atma-Sphere M-60's with a pair of Paul Speltz's "Zero" autoformers. This will give you true OTL magic, and you'll still be able to drive your 4-ohm Virgos. OTL's do some things better than other amps.

Sounds like a wonderfully enjoyable quest you're on. Best of luck to you!