EVENT OPAL setting bias
Hi everyone, I thought that I'd share this situation and ask for some assistance as I "fine tune/optimize" the amps.
While my Event Opal monitors sound okay, I decided to take some measurements.
I'm the second owner and given that one heat sink operated noticeably warmer then the other, even at idle, I wanted to ensure bias is set correctly/ optimally.
And, I have some reason to believe that the first owner had been messing around inside...
There is no trim pot for offset, only for bias (white vr bias, the black vr is for output level to balance freq response)
The monitors have been discontinued for a few years.
The manufacturer set bias according to crossover distortion ( AP analyzer).
I only have access to an oscilloscope.
* The values across the 0.05 ohm resistors on the left side are suspect.
Are the other values "normal" or indicative of something not quite right?
What is the best/ optimum way to set bias for these amps?
See attached measurements, photos, schematics,etc...
Cheers
SW
Hi everyone, I thought that I'd share this situation and ask for some assistance as I "fine tune/optimize" the amps.
While my Event Opal monitors sound okay, I decided to take some measurements.
I'm the second owner and given that one heat sink operated noticeably warmer then the other, even at idle, I wanted to ensure bias is set correctly/ optimally.
And, I have some reason to believe that the first owner had been messing around inside...
There is no trim pot for offset, only for bias (white vr bias, the black vr is for output level to balance freq response)
The monitors have been discontinued for a few years.
The manufacturer set bias according to crossover distortion ( AP analyzer).
I only have access to an oscilloscope.
* The values across the 0.05 ohm resistors on the left side are suspect.
Are the other values "normal" or indicative of something not quite right?
What is the best/ optimum way to set bias for these amps?
See attached measurements, photos, schematics,etc...
Cheers
SW
Attachments
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left amp.jpg894.2 KB · Views: 307
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left drivers.jpg667.8 KB · Views: 287
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left ground wires .jpg503.3 KB · Views: 280
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left input.jpg758.1 KB · Views: 264
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left ps.jpg961.3 KB · Views: 262
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datasheet.pdf240 KB · Views: 61
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opal amplifier measurements.pdf50.2 KB · Views: 104
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low freq amp schematic.jpg147.9 KB · Views: 228
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hi freq amp schematic.jpg137.2 KB · Views: 222
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