Entech 203.2 DC offset question

theAnonymous1 · 2nd February 2007, 03:49 PM

I have an Entech 203.2 DAC I want to DC couple to an amp but there is -13mv offset on one channel and 9mv on the other. The output op-amp is an OPA2134PA.

Is the DC offset coming from the op-amp, or is it possible that something before the op-amp like the CS4329 is causing it?

If it is the op-amp, would it be possible to use two OPA134PA on an adapter to be able to trim the offset?

Thanks in advance.

theAnonymous1 · 3rd February 2007, 01:52 PM

Anyone??

stephensank · 4th February 2007, 01:34 AM

Such a low offset voltage is absolutely not worth worrying about, and may actually disappear when the blocking cap is eliminated. Even if it remains(and is almost certainly the dac chip's fault), it will not have any negative effect on your preamp/amp or on the sound. If it was near or over 100mV, then it would be something to try to remedy, with either an offset adjust resistor/pot circuit, or with adding a dc servo amp to each channel.

theAnonymous1 · 4th February 2007, 01:30 PM

Thank you very much for the reply. If for any reason I do have an issue, I guess I will try try putting in the adapted OPA134 with offset trim circuit.

2nd February 2007, 03:49 PM	#1
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	Entech 203.2 DC offset question I have an Entech 203.2 DAC I want to DC couple to an amp but there is -13mv offset on one channel and 9mv on the other. The output op-amp is an OPA2134PA. Is the DC offset coming from the op-amp, or is it possible that something before the op-amp like the CS4329 is causing it? If it is the op-amp, would it be possible to use two OPA134PA on an adapter to be able to trim the offset? Thanks in advance. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

3rd February 2007, 01:52 PM	#2
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	Anyone?? __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

4th February 2007, 01:30 PM	#4
theAnonymous1 diyAudio Member Join Date: Feb 2004 Location: Anonymityville	Thank you very much for the reply. If for any reason I do have an issue, I guess I will try try putting in the adapted OPA134 with offset trim circuit. __________________ "If you don't like funerals don't kick sand in Ninja's face." - Ninja

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4th February 2007, 01:34 AM	#3
stephensank diyAudio Member Join Date: Oct 2006	Such a low offset voltage is absolutely not worth worrying about, and may actually disappear when the blocking cap is eliminated. Even if it remains(and is almost certainly the dac chip's fault), it will not have any negative effect on your preamp/amp or on the sound. If it was near or over 100mV, then it would be something to try to remedy, with either an offset adjust resistor/pot circuit, or with adding a dc servo amp to each channel.

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