plumsolly
Well-known member
I was running some frequency tests on my Auditronics 110 console today and I realized that all the channels have a disturbing high frequency rise when they are at their lowest two gain settings. See the graph here:
When the gain is turned up beyond the first two points, it evens out to a normal looking response. I changed the mic amp chips in most of these to 5534s and some of them I put DOAs in - the symptoms are the same for both. The first thing I did when I realized what was happening was to add a 150/120pf cap across the feedback network - (this is recommended in the Auditronics literature for upgrading to 5534's to limit the bandwidth of the amp stage to prevent high frequency oscillation) This didn't help. Then I added a 22pf comp cap between pins 5 and 8 of a 5534 channel to see if that would help. It did not.
Any thoughts would be really appreciated - thanks, Ben
When the gain is turned up beyond the first two points, it evens out to a normal looking response. I changed the mic amp chips in most of these to 5534s and some of them I put DOAs in - the symptoms are the same for both. The first thing I did when I realized what was happening was to add a 150/120pf cap across the feedback network - (this is recommended in the Auditronics literature for upgrading to 5534's to limit the bandwidth of the amp stage to prevent high frequency oscillation) This didn't help. Then I added a 22pf comp cap between pins 5 and 8 of a 5534 channel to see if that would help. It did not.
Any thoughts would be really appreciated - thanks, Ben