The Sunn amps are real mutts form a design perspective. Everyone knows the Sunn Model T, America's first attempt at a high gain design, but Sunn was cranking out more vintage featured amplifiers (particularly bass amps) for a long time before attempting to innovate too heavily. Like most of tis cousins the Solarus has a Fender inspired preamp. It has the global 2 band EQ of a tweed era Bandmaster, Pro or Super, but the implementation of the EQ and gain stages is more blackface in nature. The power section of the Solarus is a vintage Hifi affair based around the old Dynaco ST70 featuring dual 6550 output tubes pushing a good 70 to 80 watts of clean headroom with extraordinary transient response (though Sunn rated them conservatively at 60 watts RMS). You can cut the power on these amps by modifying them to accept EL34 tubes. The bass will tighten and the headroom will decrease making them sound a bit Hiwatty. That said, they make such a bold statement stock that I would personally leave well enough alone if I ever owned another one.
The Solarus is one of Sunn's few guitar models and like its cousin the Scepter (still not sure what the difference between these 2 really is) it features tremolo and spring reverb in the Fender style that sound pretty decent. this is a wonderful platform for pedals as it has huge bandwidth and monstrous headroom. If you can stand the SPL the Solarus can produce some nice overdrive tones once you start driving the PI and output stage. The biggest fault of this amp is that it uses the Dynaco PI circuit which, while a wonderful design, requires a rare, out of production 7199 tube or needs to be modded to accept the slightly more common 6AN8 tube. I believe electroharmoix has reissued the 6AN8, but I do not know if its up to snuff as this tube contains a hi mu preamp pentode similar to the EF86 and 5879, and for reasons that escape me no one can make decent current production EF86.
Still a real sleeper and a great amp in the mold of the twin reverb... only bolder and cleaner. Sunns are like America's answer to Hiwatt. This amp will make you very uncomfortable if you don't wear ear plugs and will cause the audience to back up a few feet if you can get her turned up to the sweet spot for optimal clean tone. Pushed into overdrive she holds her own with a 100 watt Superlead and is an effective device for killing bratty children without leaving fingerprints on their bodies. Too much amp for most people, but still a mighty offering from one of America's best and least respected manufacturers.