The 6T9 tube has both a triode and a pentode in the one small compact glass envelope. The amp uses Spare Time Gizmo cct. brds. and is in SE UL mode. This is the second of the two amps I built. The first was on a Teflon $7 baking pan chassis. Edcor XSE15-8-5K OPTs are under the lid and help produce a frequency response from 20hz to 20khz (-3db points).
The sound stage produced is extremely wide and deep and when coupled with a pair of Fostex single driver 94db efficient speakers produces the most sumptuous music. Especially classical and voice. The paint used is Epoxy enamel and though the two coats take eight days to dry the finish is very tough.
The amp has no audible hum at 12" from the speakers and produces very sweet mids with excellent detail. At no time does the amp not sound musical and I would recommend the build to anyone wanting a very inexpensive and exceptional sounding amplifier.