[sdiy] cs4344 DAC output stage

[julian schmidt]

Am 13.09.2012 18:19, schrieb Eric Brombaugh:
> On 09/13/2012 08:30 AM, julian schmidt wrote:
>> Hello all,
>>
>> I'm designing a cortex M4 based audio/synth board using the cs4344 DAC
>> and a cs5343 ADC.
>
> Cool! I've got a couple projects like that in the works too:
>
> http://ebrombaugh.studionebula.com/synth/stm32_4chl/index.html
>
> http://ebrombaugh.studionebula.com/synth/stm32f4_codec/index.html
>
> The hardware design was fairly easy - I'm finding that the firmware is 
> a lot more fun.

what kind of elkos did you use? My board is full of the big aluminum 
elkos for the DACs.
I just see the small smd packages on your board. Did you use Tantal? Any 
pro's or con's for alu. vs tantal besides the size?
I havn't done much smd design until now ;)

nice board by the way. glad to see some other people poking around with 
ARM chips.

I see you used an usb power source in one of the designs.
What have you done against noise introduced from the USB port?
while using the discovery board (and other usb devices) I noticed a 
ground loop(?) introducing noise to the audio outs as soon as usb and 
audio out was connected to the computer.

Do you like the overall sound quality of the cs4344?

julian
>
>> As i'm new to designing with DAC/ADCs here's a question.
>>
>> Is there an opamp needed for the DAC output stage?
>> I've seen opamp output stages in quite a few designs using different
>> kinds of DACs, but the datasheet for the cs4344 just states some R/C
>> filters after the dac output as reference design.
>
> That really depends on the signal input requirements of the equipment 
> you're driving it with. The CS4344 data sheet circuit gives a 
> recommended hookup for line-level outputs, sufficient to drive ~1Vpp 
> signals for typical audio line inputs. It's not enough for the ~5Vpp 
> signal levels typically used in modular synthesis applications though. 
> In that situation you'll want some gain.
>
> Eric
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy