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Help needed for my DIY DAC

Wharfedale Speakers

cha_indian

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Dec 14, 2007
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My PCM 1798 DAC kit (WIP)

Hello guys,

I have almost completed soldering a DAC kit and would be testing it very soon. I am not sure whether i soldered the correct resistors and was wondering if i could test them before i power the DAC ??

Also the chassis is made of teak wood. Can you guys help me in grounding the DAC?? what is the best way to ground a wooden DAC ?



 
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cha_indian

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Dec 14, 2007
Messages
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Location
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Thanks for all the replies guys....

The kit is HiFiDIY's PCM 1798 kit. It costs 159 USD.

Cranky, I am sure i have soldered the correct resistors because i checked and double checked, but still ..... !!! This being my first foray in to DIY world iam jittery just like the citizens of Andhra and Telangana :lol:

Guys, would a wooden cabinet induce unwanted radiations into the board ??
 

cmsajith

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My suggestion would be to use the power supply in a spearate (may be metal) box and bring only the required DC current to the wooden DAC box and you can keep the power supply away from the wooden box.
 

cha_indian

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The thing is that there is no seperate power supply..... I the power regs and caps are integrated into other dac components and whole thing is only in piece of board.

The transformer is R-Core
 

sachi

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In my experience, DAC's aren't as susceptible to magnetic fields generated from a transformer's winding.

I wouldn't worry about separating the transformer from the DAC for the time being.
If you do have problems one way of reducing magnetic field effects would be to use mu-metal foil. There are some who have used this to shield their toroidal transformers in headphone amps and preamplifiers with varying degree of success.

Reducing EMI can mostly be acheived by proper layout and circuit design techniques. Anything after that stage is going to be cumbersome to implement.

AS to worrying whether you have the resistors in place right or not..well if you have double /triple cehcekd with the schematic and the components are where they should be, then just throw the switch (keep a bucket of sand ready just in case ;) )
 

cha_indian

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Thanks for the replies guys...

Another issue with my plan is to separate all the ports (sockets) from the DAC board. I want to mount all the input and output ports directly on the back plate of the case. .... there are Optical input, SPDIF input, Analogue RCA outpout, USB inputs ports that are to soldered on the board itself.

Can you give my some ideas as to how to mount all the ports on the case ??
 

sachi

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Location
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Thanks for the replies guys...

Another issue with my plan is to separate all the ports (sockets) from the DAC board. I want to mount all the input and output ports directly on the back plate of the case. .... there are Optical input, SPDIF input, Analogue RCA outpout, USB inputs ports that are to soldered on the board itself.

Can you give my some ideas as to how to mount all the ports on the case ??
Well in this situation you just move the board over to the edge of the case and drill holes in appropriate places so they align with the board giving you access to the inputs and outputs. At the very least the side which has the toslink input needs to be flush up against one side of the case.
 

cha_indian

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there are some practical problems with moving the board towards the backplate.

I want to build a seperate board that has all the ports and then fix the board to backplate..... I needs ideas on how to fix the board to backplate...
 

sachi

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there are some practical problems with moving the board towards the backplate.

I want to build a seperate board that has all the ports and then fix the board to backplate..... I needs ideas on how to fix the board to backplate...
It would be messy , mainly for the digital inputs. The outputs you can just run the wires from the main board to the back panel.

WHat kind of problems would you have with moving the board right up against the rear panel?
 

cha_indian

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the plan was also to integrate my EHP 606 into the same box and make the DAC+EHP606 into one single unit . There was also a plan to fix in a DVD Drive on the front plate.

The problem is that the back plate cannot take all the ports of DAC as well as EHP606. Space is the constraint. I also have find space to install a cooling fan.
 
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kaushik

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there are some practical problems with moving the board towards the backplate.

I want to build a seperate board that has all the ports and then fix the board to backplate..... I needs ideas on how to fix the board to backplate...
Grab an Araldite rapid ,make your own plate for back plane
like this:
A grainy looking plastic will be beautiful,take thin plastic cover from a business notebook(not laptop :D).Attach to a cardboard. Do drilling and fit sockets etc .


To fit it on wood dont use screws it will spoil the look,use Araldite rapid.do a window cut on back of wood box,put that epoxy from inside stick the plate,done!. You need pic?
 

cha_indian

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Location
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Can anyone explain the process of wiring a Rcore transformer. The diagram given in the manual is like:

Red----------
115V 50Hz
Blue----------

Green--------
115V 50Hz
Black---------

The above respresentation is the primary. There are many secondaries and i plan to check the voltages with multimeter after the primary is sorted out.

What needs to connected together to make a Negative, Positive and Earth wires so that i can create a cable.

Hope
 

sachi

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519
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Location
Portland, Oregon
Can anyone explain the process of wiring a Rcore transformer. The diagram given in the manual is like:

Red----------
115V 50Hz
Blue----------

Green--------
115V 50Hz
Black---------

The above respresentation is the primary. There are many secondaries and i plan to check the voltages with multimeter after the primary is sorted out.

What needs to connected together to make a Negative, Positive and Earth wires so that i can create a cable.

Hope
you basically wire up the primaries in series.

Which means you join blue and green together, then red and black are your active AC leads. Red goes to Neutral, black goes to live.

As reference Transformer wiring
Edit: Please be sure to wire it up right before applying mains AC..if u have it wrongly wired you'll see some fireworks. be extra SAFE when dealing with AC mains..always insulate all AC points.
 
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