Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Loquah on November 12, 2012, 04:39:15 PM
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Hi all,
Not sure if this belongs here or in the technical thread so apologies if it's misplaced.
I have just finished building my Crack and in voltage tests everything tested well except for a significant voltage difference coming off pins B4 and B1. I read 80V on B4, but 87V on B1. The manual says that 10-15% variation is expected, but everything else was much closer to the readings in the manual so I thought it was worth checking in.
I'm a complete newbie to circuit design. Good with a soldering iron, but no knowledge of what each component is doing within the circuit! :)
PS I am using 240V as I'm in Australia (in case that makes any difference)
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Could be the variation in the value of the 22k1/1W resistors? Should be fine, but wait for confirmation on this one please - I don't want to be the one to say go ahead and plug in your tubes and have you fry your Crack and say bugger! ;)
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I read 80V on B4, but 87V on B1.
Looks good, provided you are seeing the same voltages at 1 and 5.
This voltage varies by the emission of the 12AU7, which can vary a bit, especially between a new production tube and an old stock tube.
-PB
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OK, great. Thanks.
It sounds sweet so all OK. I was worried that it might have affected the L/R balance or something, but seems all good.