Hey everyone, I've been lurking on here a lot but haven't posted anything really. I just finished my first audio DIY project: the starving student millet headphone amp. I built the 12AU7 variation. I really wanted to post because I liked seeing people's finished builds... and nobody I know could understand why I wanted to build a tube amp! I thought you all might like to see, and I'm open to feedback.
I'm not going to show any pictures of the inside its a bit of a mess haha (unless you REALLY want to see what a rat's nest looks like, I wired it all point to point). The amp seems to hum quite a bit, but I havent figured out if its the input, or the headphones. I actually managed to blow one of my speakers in my over-ear headphones while building this ( i didst realize a mosfet had shorted and accidently sent ~48v to my headphones >.< ) I ordered a replacement speaker and should have my headphones fixed in a week or two.. Right now I have it hooked up to my (powered) desktop speakers, with an optical DAC connected as the input from my PC. There is no hum whatsoever in this configuration, I'm guessing its because the speakers are grounded in a much better fashion then when I plug in my headphones. any thoughts on this would be great. It sound fantastic through my desktop speakers, it was kinda cool to be able to switch instantly back and forth from my computers audio out to the amps output and hear the difference.
I had a lot of issues with properly mounting the volume potentiometer, and I somehow ruined the functionality of the pot while trying to superglue washers to it haha. In an effort to get it done and tested, I went ahead and wired a 100k and 50k resistor in series on both inputs in place of the potentiometer. I can adjust the volume on the input side for now.. I have another potentiometer coming in the mail in a few days, i might have more luck with that.
i got a couple of different tubes. I got two cheap Ei's to test with after I managed to fry one of the 30$ sylvania black plates i got. I havent listened to the RCA's yet. So far the Sylvania's sound very smooth.
This is the box I found for 5 dollars at a flea market.
here it is finished. it should have a volume knob soon haha. the pliers give it some size reference
here it is plugged in on my desk.
birds eye view
Well that's all I got for now. I did have some classmates that got interested in the project, and we ordered a couple PCB's from someone on here, and are gonna build those in the next few weeks. I'll post those if you all are interested. Thanks !