have you ever bought stereo without listening first

Yes.   But I tend to read reviews and look for consensus opinion.  IE- if one reviewer considers a piece to be the best ever, while other reviewers say it is just -ok- then maybe it is just -ok-.    Or if all reviews, across multiple platforms etc, agree that the component is wonderful, that also sends a powerful message.

I have purchased the following without prior audition:

KEF LS50
ARC SP-10mkII
AT 33ML-OCC
Lundahl and Cinemag SUT
Marantz SR7009 (then TOTL HT Receiver for our Den)

While an audition helps in decision making, a new component represents a variable that you will not be able to confirm until the component is in your home, in your system.   Still a leap (but smaller) faith.

I prefer home demo.  Only time I did not was when I upgraded from Pass Labs Xa30.5 to XA 100.8.  Yet I was anxious until after burn in period .  I made the right decision.   If you have experience with another amp from the same brand in your current system then  upgrade should be safe  

It's almost impossible to audition a phono cartridge in a meaningful way before you pay for it, in my experience. All the other components I have 'bought' without hearing first have had a reasonable return policy. Luckily, few have had to be returned because, like many others have said, I research the hell out of stuff.

PS. I have been to Audio Connections many times and I respect their experience and opinions. Don't worry @Iobinero, if your not delighted; John will make it right.

OP, you made me think. Of everything that has passed through my hands over the last 40 years or so, only one item had a real demo (and a public one at that at a large dealer in the UK) - the original Kef Reference 105. I was so impressed I brought a pair to the States when I emigrated, and still have them, but not in use. All of my subsequent speakers were bought without audition (PSB, Quad 2905, KEF 207/2, and Stax headphones). But as my mind runs in small circles, I tend to move up the chain with manufacturers I have known. For instance a college roommate had Quad ESL57's which put me on the Quad path, and the KEF 105s lead to the 207s. Everything on the electronic side was after reading reviews and info on audiophile web sites, or being in the right place at the right time picking up demo or clearance equipment locally, hardly ever with a demo. But I had done my research at least, and what I bought turned out fine, with only a couple of disappointments (both were CD players).

I have a lot of respect for Belles. I still own one of the first amps he made, the Belles A, and it has stood up very well over the years (aside from the habit of welding the switch contacts together at turn on). It will drive into 1 ohm loads.

It is my understanding that he still makes his gear himself, so you are getting a potential collector's item.