Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: clauswitz on April 05, 2011, 08:35:07 AM
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I've just completed building my Crack and all the resistance and voltage checks are correct except for the very last check to see how high the voltage to the headphone jack spikes after you turn it on. Mine gets up to about 11 volts and the manual says don't plug in headphones if it get much over 9 volts. I just don't know if 2 volts is much over since on one hand its just 2 freaking volts, but on the other hand it is over a 20% increase. Any advice on this so I can start using this great amp would be much appreciated.
Thanks in advance.
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Leave your meter connected there for a few seconds with the amp on and you will see the voltage drop. After it drops there is no problem at all plugging in your headphones.
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Ah, I forgot to mention that it does drop back down to zero, I just wasnt sure if that 2 volts was a big deal. I was working on the assumption that the 2 volts itself most likely wasn't a big deal but that if that was a sign of another problem I didn't want to break my headphones. Especially as I'm most likely to leave them plugged in pretty much all the time since I dont have another pair that I actually enjoy listening to.
Thanks for the information. Once I get home from work I'm going to enjoy listening to the amp for awhile before I start on the speedball upgrade.
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Just leave your phones unplugged till the amp has been on for 10 seconds or so. Then there will be no DC sent to the drivers on startup.
Since it goes to zero phones will never see the "thump."
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Yes, Grainger is right, that's what I meant to say but didn't - the voltage present shouldn't be enough to be an issue, but if you want to really play it safe plug them in about 20 seconds after you turn the amp on.