Buzzing newly-built Crack [resolved]

DeweyCH · 342

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Offline DeweyCH

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on: March 05, 2021, 01:05:58 PM
Hi all, I finished my first Crack build today and cannot for the life of me find the buzzing/humming cause. It's a low-to-mid-level buzz that happens regardless of tubes and regardless of anything being plugged into the RCA jacks, and while it plays, after about 10 seconds there was a loud "Pop," and I turned it off and haven't tried it again. It kept playing after the pop but... yeah. Not gonna blow up anything out of ignorance if I can help it.

Going to go diving into it further once the kiddo goes to bed, but thought I'd lean on the forum here for advice. I have gone through and inspected/reflowed seemingly all, or at least most, of my solder joints, and I followed the Crack Grounding, Tracing the Signal etc. post. All of them came back as properly grounded, although it also says to check transformer terminal 4 to 22, but mine doesn't seem to have those.

Resistance:

1 - N/A
2 - N/A
3 - 0
4 - N/A
5 - N/A
6 - 0
7 - 2.92k
8 - 0
9 - 2.96k
10 - 0
12 - 0
13 - N/A
14 - 0
20 - 0
22 - 0
B3 - 2.92k
B6 - 2.96k

Voltage:

1 - 85v
2 - 176v
3 - 0v
4 - 176v
5 - 80v
6 - 0v
7 - 107v
8 - 0v
9 - 107v
10 - 0v

Pics attached. More on request. Thank you all very much in advance.

« Last Edit: March 05, 2021, 03:53:00 PM by Paul Birkeland »



Online Doc B.

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Reply #1 on: March 05, 2021, 01:40:42 PM
You need to fully solder the inboard black wire connection on the headphone jack. Probably the most common error.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline larcenasb

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Reply #2 on: March 05, 2021, 02:20:34 PM
Nice to see you got your kit and have it built, DeweyCH! Try not to get frustrated--Bottlehead kits refine invaluable troubleshooting and problem-solving skills. There's always a reason something may be wrong, and with a cool head we can discover, fix, and understand it. Cheers and I hope you get your amp singing soon!

Lowell B.


Offline DeweyCH

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Reply #3 on: March 05, 2021, 02:45:55 PM
Oh my god, I thought I had that all soldered in. That did it, thank you Doc!



Offline DeweyCH

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Reply #4 on: March 05, 2021, 02:46:42 PM
Sounds great!