Preamplifier with CS3310

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Hi everyone,

First, try to understand my english, it isn't any good. But to the point, i'm planning a preamplifier to my DIY-system. You can see my plans from schematic (sry for quality), and i need some feedback about it.

First, is input and output buffers ok? Is resistance level ok?
Second, power supply: CS3310 has +/-5V for analog parts and +5V for digital part. In CS3310 datasheet, both digital +5V and analog +5V is connected together via 10ohm resistor.
Is it better use own, well regulated power supply for digital +5V?

I think that PCB would be very critical part. I have made some plannings already, but first i need to know how i made power supply.

Controlling CS3310 is already done with PIC16F84, so it wont be any problem.

- Mika, newbie here and newbie with analog electronics
 

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If you end up using the CS3310, use a separate power supply for the digital 5V. The trick is how to tie the analog and digital grounds together. One school of thought is to keep the grounds completely separate up to the IC and use a ferrite bead wire to connect the grounds. Depending on your resources, a ground plane for the analog section would not hurt either. But keep the ground plane away from any of the digital stuff. If perf boarding then you could try star grounding but watch that the length does not get too great.
The PIC could create some hash onto the ground plane when active. Good luck isolating it.
As you may know, when the CS3310 goes into mute mode, the internal amp is disconnected and an internal 10k to ground is used. So it is a good thing you are not using it to drive your interconnects as is the case in my Golden Theater GTX-1. You can hear the hum rise more than 20dB when muting and using non-sheilded interconnects like the Nordost type because you are almost like an antenna. If you don't use the mute function you could use the CS3310 to drive your cables directly if you don't mind being limited to bipolar 5volt swing. Less can be better.

I want to make a project like this for 5.1 + channel audio like DVD Audio or multichannel SACD where you need the analog domain control. My GTX-1 does not have analog pass-thru. I would be interested in how this project goes. Good luck
 
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