| Sonic t-amp, ALPS pot, crazy problem - Click HERE for Original Thread |
| Reeb |
Hi guys
Yes I am totally new here but I have been monitoring things for a while. I recently reboxed a sonic impact t-amp and it has morphed into a thing of beauty, really. I added an ALPS pot :
http://www.elfa.se/elfa-bin/setpage...dok=2012603.htm[/url]
and everything works spiiffingly...until....things warm up for 20 minutes or so and then the strangest thing happens - the volume becomes unbalanced. Turning the volume knob down reduces the volume on the right channel but keeps the left channel relativeley constant. At minimum volume (which is "off" at startup, the left channel still puts out quite high volume. Furthermore, this continues up the scale so that you have to put the volume at around 1 oclock to get balanced L/R gain. WTF ?!?! I am at a loss for solutions. The ALPS pot is brand new from a reputable dealer. I wired it according to the directions on the tnt-audio reboxing guide .
Any ideas? Anyone had this kind of thing happen before? Can a good POT warm up and go nuts?
Thanks for any help. I will attach a pic of the new amp. Screws were not in the sides at this stage so there is a gap. |
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| anatech |
Hi Reeb,
Sounds like your pot is losing it's ground reference on the left channel. Could be a thermal fault in the pot.
Take it out and hook up your meter to it (or do that in the case). Heat the pot up with a hair dryer, or use the amp to do it. You may see the reading go from some value of resistance to open or very high resistance. Measure from the common pin to the hot input pin (across the control). You do not want the pot in circuit when you do this.
-Chris |
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| cowanrg |
| could it be a bad solder joint? |
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| anatech |
Hi cowanrg,
Yes, absolutely it could.
I did have a Nobel pot do this once. Drove me crazy since it was thermal too. Ground pin intermittent where the connection inside to the board was made.
-Chris |
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