Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Pfenning on June 23, 2012, 09:05:28 AM
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So this topic started in the headphone area of the forum when I was commenting on the poor sound quality of my new Beyerdynamics DT 990's. I discovered through some conversation with the forum that I had a wiring problem. I tracked down my problem and corrected it, and it made a huge difference. Now my problem is the volume isn't the same in both ears. I swapped headphones, sources and cabling to make sure my problem wasn't from the source. I posted this and Doc recommended I recheck the voltages. I followed the manual and rechecked everything. All measurements were well within 10% except pin 9 which was suppose to be 100 and measured 115, and pin B6 which was suppose to be 100 and measured 114. These are still within 15%, but the others were all so close that these jumped out at me the furthest off. What do you guys think? The right channel is the quiet one.
Pfenning
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Are the channels imbalanced at all positions of the volume pot? Does the imbalance change as the volume is raised? Both of these could be a problem with the pot.
If you have a different pair of tubes or one extra tube try swapping.
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I swapped tubes, and tested with my ipod, and it seems to be fine now. I hope to get it back into my system early this week to test it out. Thanks for the help.
Pfenning
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Just a note ... everything could be perfectly fine electrically and you may experience some channel imbalance at low volume, maybe below 9 or 10 O'Clock of the range. Or, you may not. If you do, it's only because the Alpha pots dont all track well at the lower end of the range. Some are worse than others. Point being, there wouldnt necessarily be anything wrong with the amp, or the pot for that matter. They sound fine otherwise, atleast to my ears.