Hello Bottlehead friends!
Would just like to detail a unique transistor issue that I was dealing with for the past few days, and was able to resolve. If you happen to have similar sound issues as I describe, check the integrity of your transistors.
Recently got my hands on a beautifully built Crack 1.1 that someone no longer had the time to operate, and couldn't justify letting it sit unused. He had purchased a Speedball Upgrade kit, but never installed it.
(https://bottlehead.com/smf/proxy.php?request=http%3A%2F%2Fi63.tinypic.com%2F2z3uek1.jpg&hash=ed2c8889d5f40a929acd7adce380989b)
I went ahead and installed the Speedball a few days after listening to stock Crack. First startup loud --- HUMM BUZZZZZ--- (even with pot at lowest setting). I thought to myself, GREAT! My soldering skills suck and I've cold soldered a joint and lifted the ground.
Went through the gamut of voltage, resistance and ground checks. Reflowed any joint that looked the minor bit suspect. Everything seemed fine: LEDs all lit, no loose bolts, audio signal even came in fine, but the buzzing was overwhelming.
One interesting thing though, when I hooked the positive lead on my DMM to B+ on the large PCB the buzzing went away... Finally, after much research and deliberation, I thought back to the parts that were included in the Speedball kit. For some reason, there were 2 extra transistors included by the previous owner. The lettering on them were mostly gone, they looked old and bit rusty...so I figured they were just old transistors that Bottlehead replaced with the newer shinier ones.
Turns out I was wrong
! The newer shinier ones were the counterfeit Korean 2N2907 transistors as noted here in 2015:
Cleaned up the leads on the replacement transistors with some jewelers polishing cloth, soldered, and walah! Sonic bliss. Only wish that the guy who gave me his Crack had bothered telling me that TWO years ago Bottlehead had sent replacement transistors to fix this problem!
On a lighter note, the Speedball has totally made the Crack sound like something that I cannot even begin to describe. Pairing with my 1st-generation Beyerdynamic T1's and I don't think I've ever heard music so good (like you want to cry
cause the music is so euphonically good
). Good luck to those of you building the Crack/Speedball and hope any issues you may have can eventually get resolved. Thank you to all the people who work at Bottlehead! If it wasn't for your great product and service, none of this would've been possible!
