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westers  
#1 Posted : Thursday, December 3, 2015 11:32:45 AM(UTC)
westers

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Hi

I'm planning on using a Sympatico with a Mesmerize DCB1 Buffer, hence no coupling caps in any of those systems to protect against DC on the ouptuts.

I have a Raspberry Pi and an iqaudio i2s Dac (directly attached to the Raspberry Pi board), and want to use this as a "dip my toe" into computer based audio. In discussions with iqaudio, they've informed me that they don't have dc caps on their dac outputs. Instead, the DAC internal line drivers use a charge pump to generate a -ve supply and so the output swing is an ac-coupled signal. Any dc offset is corrected through feedback and because of this, is likely to be very small, somewhere in the 100uV region

My understanding of the above is that the DC on the outputs of the iqaudio can be considered as not an issue, and thus no additional DC protection caps need to be put into the Sympatico. Is that a fair assumption?
westers  
#2 Posted : Thursday, December 3, 2015 7:36:43 PM(UTC)
westers

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I've done some more digging and I'm 99.9999% sure I don't need to worry about this. Most diy designs get you to measure DC offset, and they're saying that mV's of DC offset is fine, so if we're talking about uV's off offset, that's not going to be any cause for concern.

I'd still be interested in your thoughts though.
Brian Donegan  
#3 Posted : Thursday, December 3, 2015 8:20:43 PM(UTC)
Brian Donegan

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mV is nothing to worry about in general.

The Sympatico's differential front end can deal with more offset than you have easily.
westers  
#4 Posted : Friday, December 4, 2015 4:13:31 PM(UTC)
westers

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Thanks Brian, I thought I was worrying about nothing, however good to get some expert confirmation.
vladimirb0b  
#5 Posted : Sunday, May 22, 2016 5:13:01 PM(UTC)
vladimirb0b

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Worst case scenario, how many volts can it handle with the center tap as the only ground?

I am in the same boat as the OP, trying to avoid caps from the signal path. My simulator pegs it to the V+ rail with 1V in but it might not have good models.

Thanks!
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