Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: larmader on January 29, 2019, 01:47:25 PM
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The volume pot on my crack build has a section of the sweep that doesn't change the volume very much. That is, as I turn the knob to increase the volume, it seems like there is a section about mid-way through the full range of the knob that doesn't change the volume very much compared to the beginning and the end of its arc. Is this normal? Is there a way to get a more "even" (linear?) volume pot?
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This isn't particularly abnormal. If the channels are well balanced then there isn't anything to worry about.
Usually we get the opposite wish, which is for the first 1/4 of a turn on the pot to be stretched out to be more like the first 1/2 of the turn, as so few folks find themselves with the pot all the way up.
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Audio pots are called "logarithmic" but are actually two linear sections. So the region between 1/4-1/2 and the region between 3/4-full are kind of flat. To get a more constant change rate, you need to get stepped attenuator$.
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So the region between 1/4-1/2 and the region between 3/4-full are kind of flat.
Yeah, this is roughly what I'm getting. Thanks for confirming!
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Ok, so I thought I would post a follow up. It turns out that there was something going on with the stock 6080 tube in my crack. In addition to what seemed like unusual volume behavior, it was also exhibiting an intermittent scratchy sound in one channel. I replaced the 6080 and with the new tube the volume knob behaves differently. I can't turn the volume up nearly as much before it gets quite loud. With the previous tube I could turn it way up. This tube also fixed the scratchy sound.