Author Topic: ENSONIQ DP/4+ DC Offset and Distortion adjustement  (Read 487 times)

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Offline renaTopic starter

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ENSONIQ DP/4+ DC Offset and Distortion adjustement
« on: August 22, 2024, 05:34:19 am »
Hello, I recently fixed an Ensoniq DP/4+ (multi effector for music) that had a few dead opamps and now I would like to adjust the DC off set and distortion.
Those parameters are adjusted with trimpots, but I don't understand what to look for and where.
Can someone help me please ? I would like to understand what those two parameters do and how to adjust them.
 

Offline Kurets

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Re: ENSONIQ DP/4+ DC Offset and Distortion adjustement
« Reply #1 on: August 25, 2024, 01:51:32 am »
I expect that DC offset is just to have signal centered around zero on the output of U16 (pin 7).  The distortion adjust pin changes the low reference of the internal PCM DAC, so presumably you would adjust this for minimum distortion in the converted digital output. As this is some kind of effects processor I guess it goes back to analog somewhere, which you could also use as a point of measurement.

Signal generator and scope with FFT function would be your friend I think.
 

Offline renaTopic starter

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Re: ENSONIQ DP/4+ DC Offset and Distortion adjustement
« Reply #2 on: September 06, 2024, 05:30:39 am »
Hello, thank you and sorry for my late response !

I've got a signal generator and a distortion meter at hand.
FFT meter would be better ?

"you would adjust this for minimum distortion in the converted digital output"
Should I monitor the digitized signal at pin 27 of the AD converter ?
 


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