CS4397 dac

[alb]

A good result then.
You are fortunate to have a wife who has sufficient interest, to be able to hear differences.
My wife seldom comments on anything, unless i emerge from the garage with some ridiculously large home made speakers.

[Tripmaster]

Im back!

Here are a few more photos of my project.
















Here is a list of the components changed so far...

C3 Jamicon 220uf
C18 Jamicon 220uf
C11 3.3uf Tant
C10 Vishay 0.1uf ERO 1837
C7 Vishay 0.1uf ERO 1837
C9 Vishay 0.1uf ERO 1837
C16 Oscon 150uf
C8 3.3uf Tant
C12 3.3uf Tant
C25 Oscon 150uf
C26 Oscon 150uf
C13 3.3uf Tant
C41 Wima 0.1uf
C19 Panasonic FC 2200uf
C21 Panasonic FC 470uf
C17 Oscon 150uf

Bypass caps are SCR 8uf with R68 resistors
Using standard JRC opamp and have also tried LM4562

The output sounds a little bit veiled and lacking sparkle. The internal coax is a 50ohm cable from Maplin. I was after 75ohm to match the 75ohm socket but the chap at Maplins said it would not make any difference because the cable length was so short.

Leo recommended keeping the transformer close to the DAC. Do you think I have mine too far?

Can you recommend changing any of the parts to help improve the sound?

Thanks

Richard

[Tripmaster]

Hi Tripmaster, just wondering what are those 2 black caps for? Could you explain your setup basically? I have done similar job, but still waiting to get Vishay for c9 . My board's analog part is intact, all I will be doing is remove those e-lytes after digital and steal signal for my lampizator tube stage.
Just interested in your approach...and those 2 black caps

Hi Stifa

Sorry for taking so long to respond I have been up to my neck in solder!

The two black caps are SCR 8uf coupling caps for the output. These were pinched from a pair of speaker cross-overs.

How are you getting on with yours?

Richard

[Makgajwer]

There is my project.
DAC is built in to the Cambridge Audio D500SE. Original output stage is unusable for me, so I decided to build tube stage. It's SRPP using E88CC. Sounds very good, far better than original opamp based circuit.
Photos and comments:
-purple frame original trafo moved to make room for additional trafo (for tubes)
-green frame additional trafo for tubes
-yellow frame filament supply
-red frame anode supply
-turquoise-coloured frame DAC board
-pink frame tube output stage
http://www.audiostereo.pl/zalaczniki/1167490_1.jpg
http://www.audiostereo.pl/zalaczniki/1167490_2.jpg
http://www.audiostereo.pl/zalaczniki/1167490_3.jpg

[fordgtlover]

There is my project.
DAC is built in to the Cambridge Audio D500SE. Original output stage is unusable for me, so I decided to build tube stage. It's SRPP using E88CC. Sounds very good, far better than original opamp based circuit.
Photos and comments:
-purple frame original trafo moved to make room for additional trafo (for tubes)
-green frame additional trafo for tubes
-yellow frame filament supply
-red frame anode supply
-turquoise-coloured frame DAC board
-pink frame tube output stage
http://www.audiostereo.pl/zalaczniki/1167490_1.jpg
http://www.audiostereo.pl/zalaczniki/1167490_2.jpg
http://www.audiostereo.pl/zalaczniki/1167490_3.jpg

What are those great little tube PCBs and where can I get some. Nice job BTW.

Cheers

Rob

[fordgtlover]

Hi!

I just want to thank for all the great help I found here.

Just for fun I did a measurement of my Lawrence DAC before I started modding.

This is the frequency measurement before doing anything.



As you can see, the -3db point is at 13.000hz!

After changing out the resistors to the same value and then changing C32, C33, C34, C35 to 150pF it now looked like this!



And it sound great! My wife said that it sounded better than my extensivly modified Zero DAC. And I have to agree. Next step, better opamp and modify the power supply.

Thanks guys for the help!

Thanks for the heads up on the FR. Did you change the resisters as discussed by Leo in this post?

Where he suggests R8,R9,R14,R17 to 30k and C32,C33,C34,C35 to 150pf.

[Puffin]

Has anyone tried to connect a clock to this board?

[Makgajwer]

What are those great little tube PCBs and where can I get some. Nice job BTW.

Cheers

Rob



Thanks.
"Those great little tube PCBs" are custom made in Poland.

[fordgtlover]

What are those great little tube PCBs and where can I get some. Nice job BTW.

Cheers

Rob



Thanks.
"Those great little tube PCBs" are custom made in Poland.

Do you sell them?

[Makgajwer]

I don't sell them. I buy them ;-)