Hello everyone,
Got my Crack earlier this week, got it put together without the speedball and got it working after a bit of a scare... I should explain first that because of a bad voltmeter (I now have a new one, it wasn't an issue with a blown fuse in the old one :/) I was able to measure resistances before I fired it up for the first time but was unable to do the voltage tests. I was quite meticulous however and was fairly certain that everything would be okay, although I did notice that the LED on A8 was bit dimmer than the one to A3 but didn't think much of it until I started working out how the circuit works in my head... I realize now that this should have been a red flag. When I first plugged my headphones in, I only had audio in one channel (left)... So I went back and resoldered everything, and made sure all my connections were in the proper place. After all that, I had the same issue. No audio in the left channel (I think I could only hear what I believe to be the stereo crosstalk in the "dead" channel)... Finally out of desperation I started tapping the tubes lightly while listening over the headphones. First the 12AU7, I heard some funky harmonics while I tapped it, but no change... Then I started tapping the 6080 tube, and POP!!!! Issue seemingly resolved. I was very happy. All of a sudden the audio in the previously working channel sounded even better, and my other channel worked. I was so happy, and listened to music for quite some time. After a few days of listening, I had noted that I had random popping noises in the right channel...
Fast forward to today. I had built the PC boards for the speedball the night before and got around to installing them after work today. I also now have the ability to read voltages (Horrah!). To put it shortly, I have no (negative, actually. the needle on my volt meter moves "backwards") voltage on B1 (and therefore Terminal 1 and the rest of that path). The LED on A8 doesn't light up, nor do the two LED's on the offending "small" circuit board (there's no power going into the "O" terminal there however). I used the trick to run your ohm meter at it's lowest setting to see if the A8 LED functions properly, and it does.
I've come to the conclusion that I might have a bad 6080 tube, but I'm not entirely sure. What do you guys think? What else should I look for?
