Crack with Speedball - loud pop and damaged driver [FIXED]

[grufti]

450C is seriously hot for soldering electronics. Even 400C is hot. Watch your solder. You should be able to see when it gets sucked in.

[Lowercase]

When I originally built everything I had it set at 350°C and then did some of the reflowing at 400°C. I’ll keep it closer to 300° going forward.

I know I’ve had some weaker joints, but I really think I’ve got them all nailed down now. But I took a look at the 6080 on warmup again and noticed a bright spot on one side of the grid. You can see it in the video below. Is something stuck between the plates? If I plug in my headphones that’s when it arcs, it seems like something is logged in there.  Seems to have stabilized now but, the lightest tap on the amp causes sparking and then a pop in the headphones.

[Paul Birkeland]

You could try a different 6080, just to narrow things down. 

[Lowercase]

Ordered a new tube. Will report back once I get it. Thanks again!

[Laudanum]

Have had this happen with a 5998.   Didn't see any hot spot on the plate but tube would intermittently spark internally with an accompanying static in the headphones.  Was worst when first fired up but continued intermittently afterward.   Fortunately,  that tube was purchased from a reputable online dealer and they replaced it for me without issue.  5998's tend to be more expensive than most 6080's and 6AS7's.  Also fortunate in that my headphones survived unscathed. 

Hope it's as simple as a new tube. 

Best of luck.

[Deluk]

450C is seriously hot for soldering electronics. Even 400C is hot. Watch your solder. You should be able to see when it gets sucked in.

I'm using a Weller non adjustable solder station. Used it when I worked in Avionics, boards, wiring looms, black boxes etc. Always used a #7 bit, just varied the shape and size of the bit to suit the job. Now and then a #8 bit if using high temp solder. These are the Weller numbers
"The temperature rating of each tip is indicated in the part number: -7 = 700°F / 370°C. -8 = 800°F / 425°C. -9 = 900°F / 480°C"
Good solder helps. Cardas for the win. Expensive? How much do you use? I have a small reel of standard stuff that will see me out but the Cardas just works so well, with easy melt and flow.

[Lowercase]

Got a couple RCA 6AS7’s and so far so good.

I included a shot below of the 6080 that shipped with the kit. You can barely make out some black specs behind some of the thin wires. This is the spot where the arcing occurred and the brighter spot on the tube itself when running.

I noticed with the newer tubes I put in, no more sparking either when inserting the headphone jack in and out. I’m thinking the inserting of the jack was just enough to jostle whatever was in the tube to cause the spark and pop. Going to leave it running for a bit longer to see if anything happens again though.

Also curious, when I originally tested the Crack I used my cheaper Sony MDR-V6s. They are much lower impedance than what is recommended to run, could the lower impedance have caused the pop to be much louder than what would have been with my HD650s? Don’t want to risk damaging my nicer headphones, but I didn’t find any other stories of blown drivers when searching, so I would assume that’s pretty out of the ordinary. Also don’t want that to happen again while I’m listening. 

Sorry, but cannot for the life of me attach an image. Keeps telling me I’m not using a .jpg.

(https://i.imgur.com/yBL1pW0.jpg)