Loud Pop In Right Channel Followed By No Sound [resolved]

[Colonl_Charisma]

Thanks PB and Derek.

PB - I did use the white nylon insulating washers. I attached a photo to verify.

Derek - I did not know that the rosin core is supposed to burn off. I will go over my joints again with the highest heat setting. Joints are supposed to be shiny, correct?

[Colonl_Charisma]

Okay, I've been reflowing/reheating my joints and I'm seeing a lot of brownish oil coming out of them. Now a lot of them are also turning shiny.

[Paul Birkeland]

If the brownish flux hasn't come out of the solder joints, then they were never adequately heated.

[Colonl_Charisma]

I had no idea that I was supposed to do that haha. I was just touching my soldering iron to the joints. I realize now that I should have let it sit there for a couple of seconds. A lot of that brownish oil is coming out of every joint lol.

[Deke609]

I did not know that the rosin core is supposed to burn off. I will go over my joints again with the highest heat setting. Joints are supposed to be shiny, correct?

Sometime the rosin/flux just floats to the surface -- e.g., with Cardas Quad Eutectic solder -- and never burns off. But that's fine as long as its not stuck inside the joint. 

As for shiny: in my limited experience, most good joints end up shiny, not not all of them -- e.g., some joints with a lot of metal mass will cool quickly and look a bit dull, even if you've used high heat, but they're sound. What I look for is the solder turning watery - not just liquid/molten, but running like water into the joint.  It's easier to see when you use only a moderate amount of solder.  For me, the key is make sure I am heating both the wire(s) and the terminal lug at the same time. And if multiple wires attach to the same terminal, I will often go over each wire connection separately to make sure each one gets heated properly.

I often put a tiny dab of solder on the iron tip to facilitate heat transfer (it conforms to the shape of whatever your soldering and gives you greater surface area contact -- but some people think this isn't proper practice -- it works for me -- but I only use a TINY dab).  I also find it helpful to put the soldering tip on one side of the wire and apply solder to the opposite side - this way I'm not applying solder directly to the soldering tip which would instantly liquefy the solder and create the false appearance of a properly heated joint.

cheers, Derek

[Deluk]

The tip should be properly wetted before putting it on a new joint. Wipe the tip on your wet sponge  and apply a little solder. If you are unhappy with how it looks on the tip do it again. The tip should be clean and shiny with no black or brown crusty bits. You can add a tiny bit of solder to the clean tip if needed. Apply tip to the joint and use the wetted tip to the joint. Allow it to heat up properly before adding solder so it flows into the joint. Allow it to flow into the joint fully before removing the tip. Don't dab at it or move the wire. Allow to cool for a few seconds. If reflowing a joint apply the clean and wetted tip to the joint and allow it to flow fully. You may or may not need touch with new solder.

[Colonl_Charisma]

Thanks PB, Derek, and Deluk! I reflowed all joints last night. After a few more attempts at trying to diagnose the issue I have made no progress. I've decided to throw in the towel and send the amp to Bottlehead through their repair service. Hopefully, we can get a post from PB later down the road as to what the issue was so that it can help others in the future.

As of now, all resistance and voltage checks pass, LEDs light up and do not blink or turn off, and tubes burn.

Issues that cannot be resolved:
1) 6080 tube glows blue once it begins to heat up and once a threshold is reached the tube flashes with sparks in the center of the tube. If headphones are plugged into the amp during this time there is a very loud pop associated with the flash that comes from the headphones followed by no sound in the right channel.
2) If headphones are plugged in after the 6080 tube flashes, the right channel will cut out after a pop or crack is heard. Left channel seems to be operational.

[Lowercase]

Unless I missed it reading through this post, did you ever replace the power tube that came with the kit? I had something similar happen. Pop in right channel and a small spark inside the power tube. Did the whole reheating routine, but still had issues, usually within minutes of startup. Finally replaced the power tube and no issues since.

[Colonl_Charisma]

Hi Lowercase,

I did replace the stock GE 6080 tube with another GE 6080, but the same issues were still present. I ended up sending my Crack amp in for repair because I was unable to figure out the issue after re-flowing the solder joints and doing a couple chopstick tests. Once I hear back from PB I will update this forum thread as to what was causing the issue.

[Colonl_Charisma]

Hi everyone,

I appreciate all the help that I received during this post. The issue seems to have been a bad tube. I received my amp a couple of weeks ago, and I love it. Amazing sound, and I have already started tube rolling.