Hi everyone, I bought a 6AF11 for a few £s, with the intention of building a low cost, low powered, single tube amp. I was looking at a few existing designs, and came across a schematic on EL34 world for the Zeppelin Percolator, which I think sounds like what I'm after. I've attached the schematic listed here to this thread. I had a few questions though - first of all, I wondered how the rectified heater circuit worked? I'm guessing that the capacitor smooths out ripple, does the LED regulate voltage? I was also a little confused about the grounding of the filament circuit - does this all look right? The Squirrel Monkey (another 6AF11 build) has a treble control built into the NFB loop, could I essentially cut and paste this onto the Percolator? I was also thinking the Hammond 1750B transformer (5.5k primary, 8 ohm secondary) would be a good fit for the output transformer, and this power transformer. I should be able to do the entire build for about £80-100, I think. I could probably get that down further too if I can source some cheaper transformers. Thanks!