Vacuum Electron Tube Valve Preamp Amplifier Board Headphone Amp Parts Musical Fidelity Kit, 6J1 Audio Tube Headphone Amplifier, Compact Electronic DIY Kit DIY Parts (Static Bag)

Came with all components, glass tubes intact, works great. Was hard to find a cheap 12VAC power supply but I found a 750mA one for five bucks and it works fine. The flashing RGB LEDs make cool interference sounds. I am using this for guitar, intentionally trying to get distortion, so I don't care about audio quality. It sounds and works great for that though! Doesn't fit the other clear plastic case I found, some minor drilling fixed that though.

Excelente

First off the plastic case is sold separately which was a slight bummer. I did end up buying one. I tried running it initially off DC 12v which is what most power adapters are. Was quiet and distorted. Figured out I needed 12v AC and got the correct adapter and it worked. The 2 best cheap mods I have found: Either replacing R14 and R19 with 100ohm resistors or just soldering a 220 ohm resistor on the underside of those supplied two resistors. This slightly opens up the sound stage and raises the volume some. Replacing C10 and C12 with 10uf caps or just bridging the originals with 10uf caps does really help the bass response like another review said. Also getting a matched pair of GE tubes helps improve the sound over the cheap ones supplied. This will cost you about as much as the kit though. With a nice set of headphones this little preamp does sound quite good. That resistor mod to R14/R19 really helped give the volume I wanted on my headphones. They are 40ohm speakers and I doubt you would get near the needed volume on any headphones of much higher resistance.

Lot of fun i will buy more !

The only instructions you have on this is following the silkscreen on the board. No instructions or schematics. I can't really tell that the volume going in is much different than out even with the volume wide open and a headphone signal with the volume maxed. This might work well to insert line level to add the tube effect but a headphone amp it ain't. The channels are a little off balance but without a schematic or anything I am not sure how to troubleshoot.