CS4397 dac

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Originally Posted by STIFA

on Lampizator.eu I fount this text :
DO NOT TOUCH THE circuit consisting of C22, C23 and R2 !!! This is a resonator.

Problem is that the leads on capacitors act like antenna I think.

Should they be replaced with high quality SMD parts then instead?

What are your impressions?

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Be careful what type of caps are used here, I've found some in the PLL can make it sound surprisingly nasty
I'd certainly not use those ceramic disc plates which are microphonic
Its hard finding nice parts in SMD, COG/NPO should be ok for 1N , the 22N maybe harder

The resistors and filter caps in the standard differential to unbalanced don't make any sense to me in this circuit:confused: the + is supposed to mirror the -
They don't so it gives large DC offset:doh:

More weirdness with this little dac board, no wonder it was cheap:lolsign:

Finally getting around to working on this again as some more caps arrived. I am a little confused about the 4 smd caps L+- R+- next to the opamp. Should these be replaced or linked out>

Cheers

Iain

Does post no. 24 from Leo help with this?

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Originally Posted by leo

Be careful what type of caps are used here, I've found some in the PLL can make it sound surprisingly nasty
I'd certainly not use those ceramic disc plates which are microphonic
Its hard finding nice parts in SMD, COG/NPO should be ok for 1N , the 22N maybe harder

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What did you use?
What about that 3K resistor? What 4 that ?

Has changing original SMD parts on the PLL filter with new ones given improvement and how big?

Btw , maker of AYA dac will be soldering these parts as a favor, I just need to know what to put where. See you made one, gerat choice.
Thanks

LEO
I really cant find SMD for resonator PLL filter, can I use normal ones and which?

Fikus stated that they act like an antenna? True?

Thanks

Quote:

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Originally Posted by STIFA

What did you use?
What about that 3K resistor? What 4 that ?

Has changing original SMD parts on the PLL filter with new ones given improvement and how big?

Btw , maker of AYA dac will be soldering these parts as a favor, I just need to know what to put where. See you made one, gerat choice.
Thanks

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For the resistor I use minimelf made by BC components
These are a tight fit because they are equivalent to 1206 size but they will fit if you have a steady hand http://uk.farnell.com/jsp/level5/mod...=en/207337.xml

you can use 5mm sized through hole caps if you're struggling to find any decent SMD's, the key is to trim the legs as far as you can to the body.
Avoid types that are inductive, a thin film would be better than a stacked film

The sound improvement is subtle but worth it because its an easy mod to do.

The best advice I can give for this dac if you use co-ax in for the digital, DITCH the supplied phono socket and replace with a 75R BNC, the standard phono is real poor and causes problems

Maker of AYA dac, I presume you mean Pedja? if so please tell him Leo sends his regards;)
The AYA is a lovely dac!

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Originally Posted by jonners

Does post no. 24 from Leo help with this?

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Doh :doh: Knew the answer was in here somewhere, don't know how I missed that page when going back through!

Ta

Iain

If your using the standard output stage and intend on bypassing the four caps after the dac you MUST use some caps on the output (left and right out on the pcb socket) because of the DC offset, I'd bypass the pair of crappy standard tiny things and use better quality fitted to the output cable feeding the phono sockets

if you fancy a bit of smd resistor soldering there is some alterations you can do to eliminate most of the DC offset

Quote:

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Originally Posted by leo

If your using the standard output stage and intend on bypassing the four caps after the dac you MUST use some caps on the output (left and right out on the pcb socket) because of the DC offset, I'd bypass the pair of crappy standard tiny things and use better quality fitted to the output cable feeding the phono sockets

if you fancy a bit of smd resistor soldering there is some alterations you can do to eliminate most of the DC offset

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Ok, any thoughts on values for this. I have various ones spare but very few decent "audio" caps apart from some 100uF Oscons and some 10uf Wima's. Alternatively I could be up for having a crack at the resistors. Taking the smd caps off was easy enough. Should I measure the DC on it?

Apreciate the help, learning as I go :)

Iain