Audio Note Interstage Kit - Who's heard this?

I'm fascinated with the idea of building this kit. It's really quite an investment if you go with the double C transformers and the associated upgraded caps and resistors.

Is this a world class amp in the end?
Perhaps you will get an informed answer by posting your question on Audio Note Kits Forum.

I personally own an Audio Note L3 Kit pre-amp that is a fine performer and a very good value. With most of the Audio Note kits you can start with the basic, lower cost configuration and upgrade selected parts later as you wish.
I'm looking for a broader opinion. Of course the folks in the Audio Note forum are highly enthusiastic about the Audio Note kits.

More hopeful about a comparison between this interesting tube amp and say, a Cary, or a Manley. I just don't see much enthusiasm here is this highly educated broad brushed forum.
I am a member of the "highly enthusiastic" AN kit forum, but despite my bias I will aim to answer your question as honestly as I can! For five years I have lived with and listened to the interstage monos and also my Kit1, a 300b stereo amp from Audio Note. In that time I have also had a lot of fun restoring several vintage amps and so I've had the opportunity to compare them all.

In the end--and to try to answer you question--the monos are terrific amps. I find that most people who are into DIY are as into the process as they are into the result. Some days you can count me in that camp, and on others, well I'd rather just be done and not tinker. For those who will endlessly change components I believe the monos are an awesome test-bed. The configuration is sound and the quality is excellent. Andy Grove, AN designer, penned the circuit and so you know it's got potential.

However, if you are just looking to build the amps and be done with it, I think you will always have some thought about upgrades and that doubt could linger. That's where I am currently: trying to chase down the last bit of resolution and performance before spending obscene money. Who knows, maybe you will like what you heard at first listen and never have the urge. Off the carousel as they say! Ahhh, wouldn't that be nice. Well, this is (like the Kit1) an off-the-carousel type product. Or at least it's a lifetime keeper.

To me, the amps are terrific sounding. Better bass than what many will tell you is possible from an 8 watt amp. On my ANE I greatly prefer the sound without any sub and it fills my large room with truly moving bass. Midrange is astounding. My other SET amps are pretty good there too but the mono is the best I've had at home. Overall, it's for sure worth the cost of admission.

World class? Certainly. The best ever? No, probably not. There are level 5 amps that have much more dear transformers that I just "know" would be better than what I have in mine now. I have a friend with level 5 amps, and another with level 4. While I have not compared them, they all share a similar house sound. If you put together the monos knowing that sound and wanting it, I believe you will be happy.

Thanks Doug, great information. I might guess that you don't have those coveted, exotic double C tranformers?
Well, yes in fact I do. The output tx are the AN UK lowest level HiB double C core and the interestage tx are also AN UK but I have the UHiB for those. All copper, but boy do I wish I could afford the silver!

And that's not to mention caps...
I have listened to AN Kit Interstage Monos in SET configuration. The guy who built them used all Black Gate caps and the higest level interstage and output AN transformers in copper. They were fed by an AN Kits M3 Pre, AN Kits 2.1b Dac with silver AN coupling caps, ans AN Kits Phono Stage. All the gear was what could be called an extreme build with mucho Black Gates, 2w Tants, etc. His speakers are Carefre Little Big Horns with Lowther DX4 Drivers.
I had the pleasure listening to his system, as he built and ran it in over a three year period. The last and final pieces were the amps. The amps are what really made the system, the best and most powerful 8 watts that I have ever heard!
Don't hesitate build these amps!
FWIW, myself and other grown men have found it difficult to enjoy our own systems after a listen.
Thanks for the input Rodge827. I will have to explore at least one of the AN kits to build, possibly the phono stage.