My Delta Sigma USB 1.1 DAC Build

[kaushik]

I have just started working on an USB1.1 based dac... some time searching over the places and net i am able to gather components, some schematics and info .

Plan is like this :

Dac with some future add on space in the enclosure .
Metal enclosure ,with wood for styling.
Brushed aluminum front ,LED back lit logo panel,
gold plated RCA for output.

Burr Brown chip based ..
USB only for now.

Some info I would like to add:
It may not be able to beat CD player.But surely better
than on-board PC sound card.



I think these glances are enough for now.
With time i will reveal more as the build progresses ..

 

[iaudio]

I have just started working on an USB1.1 based dac... some time searching over the places and net i am able to gather components, some schematics and info .

Plan is like this :

Dac with some future add on space in the enclosure .
Metal enclosure ,with wood for styling.
Brushed aluminum front ,LED back lit logo panel,
gold plated RCA for output.

Burr Brown chip based ..
USB only for now.

Some info I would like to add:
It may not be able to beat CD player.But surely better
than on-board PC sound card.



I think these glances are enough for now.
With time i will reveal more as the build progresses ..

Kaushik, that brain of yours never sits idle does it? Is it gonna be USB only or are you planning to put \provision for optical input too?

Also I couldnt figure out the metal/wood enclosure part What did you mean by that?

 

[kaushik]

Kaushik, that brain of yours never sits idle does it? Is it gonna be USB only or are you planning to put \provision for optical input too?

this one is USB only..if any one wants optical etc..there are several designs,i can help with getting components(almost all )..planning for that type next after this one.

Also I couldnt figure out the metal/wood enclosure part What did you mean by that?

metal and wood combo like

but my look will be different with extruded aluminum on top..and bottom.Back panel will be fully made from wood.
I will but CAD drawings rendered to 3d soon ...itz some where online i kept..

 

[mnhegde]

Best of luck for the DIY project, kaushik. Keep updating the thread (if possible with pics) .

 

[iaudio]

Best of luck for the DIY project, kaushik. Keep updating the thread (if possible with pics) .

Wow, the metal wood enclosure looks lovely! Good luck.

 

[kaushik]

Enclosure concept .. is as follows ..

Front I will keep clean , no allen screws,back side L-pad and
threads on back side of aluminum is the plan.
Pic:

Electronics i can handle well ..
Suggestion for the window cut for logo (D) on aluminum are awaited.
Drill and hammer is one way .. the filing to perfection is very difficult.
any other options : plasma cut, laser cut for less in bangalore???

 

[santhosh]

Way to go mate:clapping:. Just love the aluminium and wood finish and also your drawings.

I know of a place in Peenya, Bangalore who should be able to do the laser cutting at a low price. Will get back to you with more info.

 

[kaushik]

Way to go mate:clapping:. Just love the aluminium and wood finish and also your drawings.

I know of a place in Peenya, Bangalore who should be able to do the laser cutting at a low price. Will get back to you with more info.

than you santhol2.. will wait for your PM,laser cut is only for front so will not be expensive i hope..I am searching for USB shielded cable.. there are many need to visit SP road.

 

[santhosh]

than you santhol2.. will wait for your PM,laser cut is only for front so will not be expensive i hope..I am searching for USB shielded cable.. there are many need to visit SP road.

What exactly is USB Shielded Cable? Is it just thick insulation. If you are after braided shielding sleeve, I know a shop on S.P Road where it is available. I wanted it for my speaker cables and finally found a shop dealing in these after lot of searching. I even asked a HFV member who has used it in his DIY Speaker Cable, but never got a reply.

 

[kaushik]

No ,braided cable is used for speakers .. (to cancel out inductance with the cable capacitance etc..i am not sure)
simple shielded Usb cable is good ,without ferrite beads .
According to USB.org ferrite beads may degrade the digital
signal.

As the dac is simple one lets try with a decent cable not too costly not too cheap I tested 'gefen dac' a while ago and they gave good shielded cable .I am looking for something similar.

But there is a world of USB cables for 'audiophiles'
eg. 50$ kimber to 550$ Synergistic Tricon USB might be
useful for very hi-end Dac.

 

[kaushik]

i got a shielded cable made by 'copartner'.
After seeing several designs I made board from
PCM 2702 based schematics . This is revision 1.

Pcb will be ordered,not home made so that extra pieces
can be useful for other forum members .


Next revision once done I will give order for the fabrication.
Most places tooling charge is high for PCB as Qty is less.
One of my friend in delhi has some contacts,I am hoping
to get PCBs done at a low cost through him.

Because the chip is in SSOP28 pack ,low cost methods of PCB cant be used by
fabricator. I dont want to use SSOP to DIL adapter
like:
image :

that may add unwanted effects to the audio.
here is physical model of the PCB rev 1

need to add a ground plane on top , components re re-arrangements
UPDATE1:
Dac kit arrived (it will be moded adding some extra sections and test ,that is my version 1 of dac)
.
The PCM2702 is a high-performance DAC. The output drive is kept low to minimize noise
and needed to add a buffer .

I will solder and test ,only will update at night.

 

[kaushik]

Soldered DAC chip and family members (capacitors).

Summery so far:
>I am building a PCM2702 USB dac.

thought pcb order + local build of USB dac
>plan change ,decided to run moded DAC demo
then if some people like the DAC ,will go for
full pcb and assemble. In the test demo version
the extra sections will go on GP boards.

 

[kaushik]

Getting less time ,some components came late..so going slow

op amps at output...yet to test

 

[mnhegde]

@ Kaushik : Looks very interesting. Finalised any enclosure designs (I know its a bit early to ask)??

 

[kaushik]

@ Kaushik : Looks very interesting. Finalised any enclosure designs (I know its a bit early to ask)??

the wood and metal combo is on the plan,i removed the L-pads in the design and new wood frame will hopefully fit the brushed AL front.

top and bottom will fit HDD Al enclosure..front is a AL brushed panel.

 

[kaushik]

Regulated power supply board done , finally:yahoo: ..


it is 99.8% complete ...it will power the op-amp stage.It may not look cool but should give a clean supply
until I order the pcb this GP board prototype i will use , if needed modify a bit
..oh good idea i will make the PCB art work ready , will be handy for the future.

 

[audiodelic]

looking good congrats .... :clapping: keep going

 

[vjcritic]

What software are you using to design the Chassis?

 

[iaudio]

Regulated power supply board done , finally:yahoo: ..


it is 99.8% complete ...it will power the op-amp stage.It may not look cool but should give a clean supply
until I order the pcb this GP board prototype i will use , if needed modify a bit
..oh good idea i will make the PCB art work ready , will be handy for the future.

Good job Saar! So I am sure there s gonna be full time music this weekend at your place and a listening impression in the following week of the delta sigma usb dac.

 

[kaushik]

@vjcritic,
I used ironCAD trial..
@Iaudio
sad part is Mr opamp is not available in the market, ebay devices are fake sometimes..letz see if i can get a decent audio grade op-amp from analog devices for a good price.
already told some dealers to check in mumbai.


But there is music flowing as i already made the DAC and running with slow op-amp just for trial,this resulted in lack of dynamics...
when i reach certain decent SQ level i will put a review of sound .