Stock Crack, First Build. 12AU7 and LEDs stopped working

[potable]

Hey guys, I'm really enjoying putting my crack together, but I've hit a wall and I need some help.

Let me start by mentioning a couple mistakes that might be relevant. While doing voltage checks, I sparked on the 13th terminal, might have impacted that 12+13th capacitor. Also, I originally had the 6080 socket oriented incorrectly  :-[, and had the crack on in that incorrect configuration for voltage checks.

After re-orienting the socket, all the checks cleared and the crack worked, but only in the left output. For troubleshooting, I reheated the solder to the headphone jack and when I retested it the crack had no audio, the 12AU7 tube and LED's would not light. Another voltage check showed me I had a number of terminals off:

Terminal / Actual / Suggested:

1 / 141.4 / 75-90
5 / 140.8 / 75-90
7 / 141 / 100
9 / 140 / 100

A1 / 141 / 90
A6 / 141 / 90

B1 / 141 / 90
B3 / 140 / 100
B4 / 141 / 90
B6 / 140 / 100

These two terminals arn't too far off, but they did drop in voltage:
B2 / 158.6 / 170
B5 / 158 / 170

The other terminals are within threshold.


I have some more tubes coming in, as it seems I might have damaged these with the bad orientation. However I definitely want to see if there is anything I should try or check before I try swapping tubes.

Thanks for taking the time to read this!

(Edit: just realized my suggested and actual numbers were switched, fixed)

 

[Paul Birkeland]

Does your 12AU7 glow when the amp is on?

Neither tube is drawing any current in your amplifier.  In the Crack, the twisted pair of wires leaving power transformer terminals 4 and 5 is responsible for heating both the tubes, and bad solder joints on this pair of wires will cause the exact issue you're having.

 

[potable]

12AU7 was not lighting. I re-heated the twisted pair line, to both sockets, and no change. Unrelated, I had wondered why each tube needed a dc and ac line, so its cool to know the function.


Good news is the other tubes I was planning on rolling arrived and when I swapped them in the crack otl works. Voltages are good, and I"m listening to it now. I'm VERY stoked.

I had a few hiccups along the way and this forum was a great resource for getting ideas on what might be wrong. That other user that miss-oriented the amp tube is what clued me on to what I did wrong. A bit embarrassing but hey, I still got a sweet amp in the end.

Thanks for making and supporting this great product!