According to this picture below (source) OpAmps are OPA564, TL062C, OPA1602A (which I've seen in other amps too).While DC across the pot is the "usual suspect" for crackling it is not always the case. I built a little pre-amp during Covid and was only able to get a cheap pot for it due to supply chain issues and it was noisy within a few months. I was using good op amps with very little DC offset so the first thing I tried was replacing the cheap pot with an ALPS pot and it completely solved the issue. I would try some heat from a heat gun or hair dryer to soften the glue. Not sure what op amps are used in this but if NE5533 op amps, which have relatively high DC offset, I would try a blocking cap first, if using op amps with low DC offset I would try replacing the pot first. Good luck.
According to this picture below (source) OpAmps are OPA564, TL062C, OPA1602A (which I've seen in other amps too).
What level of DC offset spec can cause this?
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This looks OK on paper, I have no idea about this brand and about potential fakes. Since it is sealed not sure how much deoxit will help.These are the specs of the volume potentiometer inside the THX-789.
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[Hot Item] 9mm RV91110g0kq Dual Unit 6pins Volume Control Rotary Potentiometer for Audio/ Amplifier
Resistance: Variable Resistor Function for Resistance: Load Resistor Installation: SMD Resistor Material: Carbon Film Resistor Packaging: Throught Hole Type: Rotary Potentiometersannidg.en.made-in-china.com
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They're about 10-15 times cheaper than a high end Alps pot. Probably worth replacing. Would be good to know if there is a DC issue though as wellThis looks OK on paper, I have no idea about this brand and about potential fakes. Since it is sealed not sure how much deoxit will help.
It will work if you can figure out how to mount it. The original is 9.5mm wide and that Alps is 27 mm wide.... this is a big difference and would require some case work and wiring gymnastics. It is a great pot... quiet and accurate with a great "feel". I don't think Alps makes 9mm pots I have used their 16mm and 27mm. For 9 mm "Alpha" is a well know brand but also lots of "fake" ones. A 9mm pot will never have the feel or performance of a 27 mm pot.Would this one work?
Alps "Blue Beauty" Potentiometers | HIFICollective
Alps "Blue Beauty" Potentiometerswww.hificollective.co.uk
Please be sure to update in case you ever find anything out. Monoprice dropped my THX 889 warranty claim because they were unable to provide a replacement unit (and I preferred to keep the current unit instead of returning for refund since I hadn't found anything better to replace it with).Bringing back this thread from the dead...
I wonder if anybody ever successfully found a replacement or solution for this?
I've had the crackling problem for a while now. My workaround is to typically just spend a few seconds turning back and forth the knob to "clean it" until it somewhat stops cracking enough in the quadrant I need to not drive me crazy while adjusting volume between tracks....
Do those have enough power to drive my HE6SE v2 headphones?