Just got my repaired Crack + SB back from @fishski13. He did a great job and really took care of me on this! Not only did he fix things up for me, he added a PSU choke and swapped out the 100uf Solen caps for some 68uf Jantzen Crosscaps. It also has a Goldpoint stepped attenuator in it, which it was pre-modded with. I had a rebranded Tung Sol 5998 waiting for it, which I got while the amp was being repaired. Anyone heard of a Sylvania 421A? I can't find anything on it, but it looks like just a Tung Sol 5998, and the eBay seller listed it as a rebrand. Anyway, the 5998/421A paired with a 6SN7 RCA (40s, VT231, opaque grey glass) sounds really damn good! Nice contrast to the Super 7. Yeah, OK, the Super 7 is still quieter, cleaner, faster, more resolving, larger, etc. etc., but the Crack + SB + mods + these tubes just has this really sweet, full, dynamic, engaging sound. Enough so that I popped those tubes in for a quick check and ended up listening way longer than intended. So, yeah, big thanks to fishski for the repairs. Really digging the amp!