@chungjh,
Thinking about your 260.8 amp. 55 degrees celsius measured at the heat sink is often referred to as optimum operating temp for many Pass amps. Reportedly, 55c is also a setup tuning point where Pass Labs sets the bias on many of their X/XA amps. It's re-checked many times during the first week of build validation testing. Bias is not set or checked until hot right at 55c. Some manuals note 55c as the sweet spot for warmup and listening time.
Last year I recall someone who finally sent their amp back in, found out it was not reaching optimum bias and temp. Simple adjustment fixed it.
Gotta infrared thermometer (heat gun) to check how fast it gets to 55c?
Thinking about your 260.8 amp. 55 degrees celsius measured at the heat sink is often referred to as optimum operating temp for many Pass amps. Reportedly, 55c is also a setup tuning point where Pass Labs sets the bias on many of their X/XA amps. It's re-checked many times during the first week of build validation testing. Bias is not set or checked until hot right at 55c. Some manuals note 55c as the sweet spot for warmup and listening time.
Last year I recall someone who finally sent their amp back in, found out it was not reaching optimum bias and temp. Simple adjustment fixed it.
Gotta infrared thermometer (heat gun) to check how fast it gets to 55c?