best k-88, 6550 under 40 each

I'm using sovtek's at the moment. I think they have a very good balance top-bottom, but I'm wondering what else is out there either in a new, or a nos. I run mostly Quicksilvers, so are there any Quicksilver guys out there?

I replaced the Sovtek 6550s in my ARC CL-60 with Valve Art KT-88s. The VA are much smoother in the midrange and got rid of the harshness I had with the Sovteks. The bass is extended and clean. The highs are crisp without tizziness. YMMV with the Quicksilvers but I love the VA KT-88s so much in my CL-60 that I have not dared to plug in a set of Tung Sol 6550s that I got for fear of losing a good thing. I bought the VAs from DIY HiFi Supply for $25 each.Charlie
The best KT 88's and 6550's that I have found are the STR KT 88's and 6550's although I personally like KT 88's a lot more than the 6550's. A customer sent me my first set as a gift for an Aronov integrated amp several years ago and I was so impressed that I have carried them ever since.