Recently acquired an AST from another member, and one of the 6V6's was microphonic. I sent an email to Swart asking for help to diagnose the problem, and got a response from Kelly within two hours. Subsequent to that email, I got several more with replacement tube recommendations - what was nice was Kelly not only pitched me on stuff they had in stock, but also sent several links to tube outlets that carried NOS stuff that would work well. Kelly also sent me jpeg copies of the original manual and tags. Now some folks might look at the above and say, "so what, no big deal." But I was honestly blown away at how helpful, responsive, articulate and friendly the Swart folks are. This is a two year old amp and I'm the second (maybe third) owner. Boutique gear doesn't automatically come with great customer service. Just wanted to give props to a company who acts like it should.