pvision
Well-known member
I have a dbx 160A with a noisy bypass switch. I had a snoop around and found 8 VDC on pin 2 of the output
I can't find a schematic for the 160A but believe it's broadly similar to the 160X & XT. The XT has a pair of 5534s to drive the output, the two opamps being used for the two halves of the balanced output
There's no 5534 in the 160A but there is a pair of 5532s. Assuming one of those to be the output drivers I checked them for DC on the outputs. IC6 is the driver for the balanced output and has 8 VDC on pin1. It has 4 VDC on the input
The 160XT is all DC-coupled apart from a blocking cap between the input buffer and the VCA. Assuming the 160A is similar I need to find where the DC is getting on to the audio path
Finding the fault is tough without a schematic and/or a layout. A schematic or suggestions how to proceed gratefully received!
Nick Froome
I can't find a schematic for the 160A but believe it's broadly similar to the 160X & XT. The XT has a pair of 5534s to drive the output, the two opamps being used for the two halves of the balanced output
There's no 5534 in the 160A but there is a pair of 5532s. Assuming one of those to be the output drivers I checked them for DC on the outputs. IC6 is the driver for the balanced output and has 8 VDC on pin1. It has 4 VDC on the input
The 160XT is all DC-coupled apart from a blocking cap between the input buffer and the VCA. Assuming the 160A is similar I need to find where the DC is getting on to the audio path
Finding the fault is tough without a schematic and/or a layout. A schematic or suggestions how to proceed gratefully received!
Nick Froome
