Successful build with zero experience [resolved]

HirkEukvic · 1270

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Offline HirkEukvic

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on: February 20, 2022, 09:30:29 AM
Well, I'm impressed. I had zero soldering experience before getting my Crack kit. Thanks to the fantastic directions, I completed a successful build in about 8 hours (seriously, I write instructional documents for a living, and the Bottlehead team definitely nailed it with these). Extra thanks to Doc B for the helpful video on how to solder. I only needed to correct one mistake (scorched the insulation on a jumper wire and had to put a new one in).

I was honestly shocked that I got my amp working on first listen since I was expecting troubleshooting headaches what with my lack of experience with anything electrical.

As for sound, the base Crack is very quiet on my ZMFs with no noticeable channel imbalance. Can't comment on musicality yet since I'm still burning in my tubes.

Question for you all though: Is it best to keep my headphones unplugged when I'm turning on the amp, or can I leave them connected? I get a loud pop when I first plug them into the jack if the kit is on, but that happens with a lot of audio gear.
« Last Edit: February 20, 2022, 02:17:43 PM by Paul Birkeland »



Offline HirkEukvic

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Reply #1 on: February 20, 2022, 09:46:15 AM
Oh, I should add that the pop is a one-time thing when plugging in the headphones, similar to connecting/disconnecting a mic or speaker from a loudspeaker system when it's turned on. I don't know if it's a cold solder joint since it's not a constant or recurring thing, and I've noticed it on some other lesser tube amps I've heard. Feel free to correct me if needed.



Offline Paul Birkeland

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Reply #2 on: February 20, 2022, 09:56:26 AM
If you're getting a pop, I would inspect the solder joint on the headphone jack where the black wires meet, as one may be loose. 

Also double check the resistance to ground at terminals 6 and 10. (they should be very close to 0, not OL)

If you have a 1/4" to 1/8" adapter, plug that into the amp and recheck the resistances at 6 and 10. (they should be 2.49K)


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline HirkEukvic

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Reply #3 on: February 20, 2022, 10:54:35 AM
Thanks, looks like the bare wire there might be loose. I'll reflow the joint later today and update if that fixes it. Terminals all passed the resistance checks last night but that doesn't mean that they didn't loosen up after I checked.



Offline HirkEukvic

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Reply #4 on: February 20, 2022, 11:39:39 AM
If you're getting a pop, I would inspect the solder joint on the headphone jack where the black wires meet, as one may be loose. 

Also double check the resistance to ground at terminals 6 and 10. (they should be very close to 0, not OL)

If you have a 1/4" to 1/8" adapter, plug that into the amp and recheck the resistances at 6 and 10. (they should be 2.49K)

If terminal 6 reports OL, what's the proper fix? 10 seems fine.
« Last Edit: February 20, 2022, 11:42:56 AM by HirkEukvic »



Offline HirkEukvic

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Reply #5 on: February 20, 2022, 11:54:47 AM
If terminal 6 reports OL, what's the proper fix? 10 seems fine.

EDIT: fixing the headphone jack ground fixed the issue. No more pop and resistances are fine.



Offline Natural Sound

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Reply #6 on: February 21, 2022, 05:41:04 AM
EDIT: fixing the headphone jack ground fixed the issue. No more pop and resistances are fine.

Good job. What will the next build be? (this hobby is addictive ;))



Offline HirkEukvic

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Reply #7 on: February 21, 2022, 05:47:21 AM
Good job. What will the next build be? (this hobby is addictive ;))

Well, I have the Speedball upgrade to install once the amp burns in a little. Then .... Ooh that's a dangerous question.   :D. I really like the look of the Mainline, eventually, but I'll wait a year or two before I can justify that.