Hi, guys, I need some help debugging my build. Spent a lot of time on this thread, read all of the little hints and suggestions but still don't have a working amp. I'm using the PCB layout, with added Tone, Bias, and MV controls.
When I plugged in my power supply (center positive but I wired appropriately) and flipped the power switch, my LED lit up, and I immediately got 12V at the center tap. The tubes' heaters began to glow, and I figured in a couple of seconds I'd see the voltage start to climb. Then, nothing. LED goes off, voltage drops. No smoke, crackles, sizzles, pops.
I went over everything I could think of, including checking the tracing for solder bridges or other shorts in the wiring. I think the tube polarity is correct (gap towards the NE555, right?). The VR was a little bent after getting it to fit, so I replaced that: no change. I also swapped out the BC547 transistor (I had socketed per FC's suggestion) as well as the NE555 without any change. When adding the tonestack, I omitted both R16 and C8. I didn't bridge the gap left by the absence of C8 (reading the updated schematic, none of the remaining connections went to ground), I figured trying that without a filter cap would only potentially fry more components.
What would be the other potential culprit components to check? I've built a few pedals and tube amplifiers so this isn't completely new to me, however problem solving beyond the simple stuff is over my head.
Thanks for any ideas!
https://dl.dropboxusercontent.com/u/23281298/IMG_3827.jpghttps://dl.dropboxusercontent.com/u/23281298/IMG_3830.jpghttps://dl.dropboxusercontent.com/u/23281298/IMG_3828.jpg(Sorry, I had originally included the pics in my post, but they were massive and I wasn't sure how to resize them in dropbox...)