First off, this project has been a total comedy of errors but it has taught me a lot of valuable lessons. It all started with my son's request for a small, tube headphone amplifier. The only tube amp that he owns does not have a headphone jack. I could add one, but what fun would that be? I had that request parked in the back of my mind for a while and then I had a power supply fail at work that had a neat, extruded aluminum case. I thought wow, that case would make a good enclosure if I could squeeze the amp into it. So I brought the box home and just started throwing stuff together without much of a plan other than it would just have a single tube pre-amp, a 6N2P because I have a box of them, and I would use a solid-state output amplifier to save space. That way I could avoid having an output transformer. The tube would lay down to make the project, kid's room friendly and it would include a headphone jack on the front and have a jack for an 8+ ohm load on the back. I happened to have a couple of TDA7266M chip amps. These are neat because they don't have to have an output capacitor and they also have a mute and standby function. At max supply voltage, they will put out about 7 watts. With my planned DC supply, the amp would be more like 2.5 watts. Previously I had used an ANTEK AN107 transformer for a small tube amp and I had an AN207 in my stash of stuff. The ANTEK AN207 is a 25 VA, 7-volt AC transformer with double primary and secondary windings. If you split the primary windings you can use the 2nd primary like a 120 volt AC isolated source. Put a voltage doubler on that, and you can power a pre-amp tube amp easily because the current draw is very low. The functional layout was supposed to be Primary Gain Stage -> Tilt Tone -> Gain Volume -> Secondary Gain Stage -> Master Volume -> Chip Amp. It required the doubler with filters for B+, a filtered DC supply from one secondary winding for the chip amp, running the heaters off of the other secondary winding. All squeezed into a 7x5x3 inch envelope. It was a nightmare. To make a long story short, I got everything in the case, but I made a wiring mistake that cost me the chip amp. Because of the way I put it together, I really was going to be hard-pressed to fix the mistake and so I pushed the mess aside and left it for another day. I have included a picture of the squirrel's nest in this post. The PT is under the cap board on the left. The vertical board in the center is the DC supply for the chip amp. The project board has the tilt-tone components, the load resistors for the tubes (to save space and keep most of the signal routing on the project board), and the chip amp. The front panel is made from 14 gauge perforated screen steel, the base and boards are made from a piece of phenolic floor covering taken from a computer floor tile. It's a regular junkyard dog. Too bad it didn't work.