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zonneveld  
#1 Posted : Sunday, December 7, 2008 3:28:32 AM(UTC)
zonneveld

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I just ordered the USB receiver module (to start with). I was just wondering if the analog output is sufficient to directly drive a power amp such as LM3875 (gainclone). The datasheet of the PCM2707 says something about 550 mV output. Do i need a preamp or can i go straight into the LM3875 for ful drive.

Gerard
Brian Donegan  
#2 Posted : Sunday, December 7, 2008 6:01:33 AM(UTC)
Brian Donegan

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You can definitely drive the chip amp directly. If you need to, you can adjust the gain resistors of the chip amp to increase it's output, but it's probably not needed.
zonneveld  
#3 Posted : Sunday, December 7, 2008 7:14:11 AM(UTC)
zonneveld

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Thanks for swift answer.

One more question about analog output: The C12-C13 and R10-R11 are there to filter out any HF still in the signal, but doesnt the PCM2707 take care of this already and couldnt you just ommit this configuration.
Dougie085  
#4 Posted : Sunday, December 7, 2008 7:22:45 AM(UTC)
Dougie085

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Before I got my Opus I was running a chipamp with the USB module without issue.
zonneveld  
#5 Posted : Sunday, December 7, 2008 7:42:12 AM(UTC)
zonneveld

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"Before I got my Opus I was running a chipamp with the USB module without issue."


I will almost certainly go for the Opus as well. I just wanted to start with the USB first to see how this works out.
And i will probably end up with buying the sympatico as well ;-)
Brian Donegan  
#6 Posted : Sunday, December 7, 2008 9:25:33 AM(UTC)
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zonneveld wrote:
Thanks for swift answer.

One more question about analog output: The C12-C13 and R10-R11 are there to filter out any HF still in the signal, but doesnt the PCM2707 take care of this already and couldnt you just ommit this configuration.


C12 and C13 are there to remove DC offset from the output. R10 and R11 provide a ground reference. Both are needed for analog output.
zonneveld  
#7 Posted : Sunday, December 7, 2008 10:18:17 AM(UTC)
zonneveld

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Oke, i thought it was a kind of zobel filter. thanks for this info! I already regret choosing the cheapest shipping option cause i cant wait to hear it play. If I buy the Opus (with PS) i will probably choose a faster shipping option!!

Thanks again
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