Wolfson WM8740 DIR9001 PCM2706 DIY DAC

[noSmoking]

Thanks,Cobretti

Hi,
I looked up the values,so I had the correct ones,but thanks for the info ,but why not just put the part# on the board,alot of mysteries I think,But all is working as it should and as soon as a DIR 9001 gets here I will test it out and see how it sounds .
Did you replace any caps I have cerafines and some panasonics in those values,and since there is vertical room use a pre reg for the 7808,or just change it to a adjustable LT1117 board that's a complete regulator(sure electronics) with low noise, The 5.0 and 3.3 are Lt1117.
Did it find the input correctly?
SO how do you like the sound you are getting and what is your set up?
Happy Listening!
Fred

 

[cobretti]

I changed all caps! Electrolytic capacitors those come with the PCB were fake. I wouldn't bother with Elna Cerafines unless you are 100% sure they are genuine. Mine caps looked suspicious with bad printing, so I didn't use them. Just picked up some good Nichicons, no rocket science. You have to put 7808 regulators where they belong. Pre-regulators for 7808 is not required (if I understand your question well). 7808 are actually pre-regs for 1117 3.3V and 5.0V regulators. I got Texas instruments 3.3V and 5.0V regs, 7808 are I believe National Semi.
"Did it find the input correctly?" What input? Do you mean USB? Yes, no problem with setup. Win 7 found it and install it within 5 seconds. I like the sound, using it on daily basis with CD player SP/DIF and my desktop PC. I use SMD TPA6120 headphone amp. from Sjostrom. Sounds good. But, I have 1/2 done b22 amps from AMB (not in th ebox yet) tested it on this DAC, the sound is about at least one grade better with these b22 amps! I was amazed what the DAC can do.

 

[noSmoking]

hi,
I will be replacing all the caps also ,I bought a bunch of Elna caps and know their genuine,got them before this crazy cap think started up,so I will use them in it,Thanks for the advice,I will have the DIR soon and will see how it sounds!
Thanks,
Fred

 

[noSmoking]

Hi Cobretti,
I think I might have fried a wm8740 (max 260 deg soldering)so I got some ordered I put the new Dir 9001 chip in and it ran for a couple of mins and started fading out ,sounded like thermal decay,but they have a new wm8741 chip now,(mouser) got alot of new features,so I have 2 of those ordered too,along with some oscons so I will put them all in when they get here,BTW does both of the 7808's get hot or just one? my one on the outside (left) gets warmer than the one closest to the inside.....I got the fully assembled board today it sounds good so far,layout was different had 2 pots and different chip layouts but most the same componets plug N play so far,lol

 

[cobretti]

Hi Cobretti,
I think I might have fried a wm8740 (max 260 deg soldering)
I don't think 260 deg soldering temperature is too high, it depends on heat up time though. I normally solder much higher, around 400 deg. C but trying to shorten the soldering time if I can. Those WM8740 I soldered with micro butane pen. I can not even imagine how hot it got when I was holdig the pen close, my guess is close to 600 deg. easy. so I got some ordered I put the new Dir 9001 chip in and it ran for a couple of mins and started fading out ,sounded like thermal decay,but they have a new wm8741 chip now,(mouser) got alot of new features,so I have 2 of those ordered too,along with some oscons so I will put them all in when they get here,BTW does both of the 7808's get hot or just one? Both (and all of them) stabilizers run hot especially 7808, it may seem they are too hot when you touch them but in fact, it is normal operating temperature. If you are concerned about the heat that might rise after while especially when you put it into the enclosure, make some ventilation holes in the enclosure.my one on the outside (left) gets warmer than the one closest to the inside..... Both of 7808 are about equally hot, they get hot because they feed another 9 SMD stabilizers.I got the fully assembled board today it sounds good so far,layout was different had 2 pots and different chip layouts but most the same componets plug N play so far,lol

 

[noSmoking]

so you use a butane pen to solder,I was concerned about too much heat,I'll try a torch and see how it does,Thanks!

 

[cobretti]

Yes. I use water soluble lead free paste and a micro torch. You should practice with a few components before you solder, just to figure out how much heat to apply and find out the melting point distance. Bringing the pen too close will burn the PCB protecting layer.

 

[noSmoking]

Hi,
I'm going to look for a torch locally, I use the water soluble flux,man that stuff really helps out,got most of the parts today wm8740 and 41's,I am getting tired so I will sleep before I tackle it,
Do you have 2 pots on your board? they are near the opamps,I have not traced them down yet,I wonder if they set the output offset?I will scope it and see after I get the kit board to working,I have 2 of them one was a kit and the other came ready to play,it has the pots on it ,same parts but not layed out the same,has better caps ,but I just read the labels,I did test several different caps on my sencore,all polycarbonates,all read the value the same but esr was just tenths of a ohm different,I want to build a opamp with removeable caps and play and see if different ones do matter.....Have you tried different caps for different sound?

 

[cobretti]

Hi,
I'm going to look for a torch locally, I use the water soluble flux,man that stuff really helps out,got most of the parts today wm8740 and 41's,I am getting tired so I will sleep before I tackle it,
Do you have 2 pots on your board? they are near the opamps,I have not traced them down yet,I wonder if they set the output offset?I will scope it and see after I get the kit board to working,I have 2 of them one was a kit and the other came ready to play,it has the pots on it ,same parts but not layed out the same,has better caps ,but I just read the labels,I did test several different caps on my sencore,all polycarbonates,all read the value the same but esr was just tenths of a ohm different,I want to build a opamp with removeable caps and play and see if different ones do matter.....Have you tried different caps for different sound?

You can grab a micro torch in Home Depot or Lowe's. They also sell a butane filler. Do you mean trimpots? No, I don't have any pots on the board. I didn't try any different caps. I purchased all caps new mostly Nichicon with low ESR, high temp and long life. I think an emphasis on CAPs selection is widely exaggerated and I am really sceptical about any sound improvement, unless, of course, you put really low grade el. caps like those that came with my board. (probably fakes from China). I don't think many people would find any difference in blind listening tests. IMO.

 

[noSmoking]

hi,
I got a torch and it is way better that I was,I have got afew traces lifted when I did it with out a torch ,I have removed and replaced 4 chips with no problems,I am enclosing a board I got with the pots on it ,I emailed him and he said it was for 0 adjust on pins 1 and 6,a new improvment!
I replaced the 8740 with the 8741 suppose to be pin compatable but it just gave out white noise so I removed and put 8740's back in and it working again,so I 've got some research to do,

 

[noSmoking]

btw the square plug that is empty is for a headphone amp out L,R G 12+

 

[cobretti]

Probably, yes. It should be the same as RCA outputs, my guess.

 

[noSmoking]

hi,
This board sounds great I am working to getting a box for it to live in it's been playing for 3 days now so we will see how it sounds in a week or so ,
btw I did put some small mostly vertical heatsinks on the 7808's and it did cool them a bit.still listening to diff opamps.....
Happy Listening!!!!!!!!!

 

[dtses]

here are few pics of mine

finished inside but still have some work on the case.

Also considering to add optical input (need it to connect LG LED). Found several options:

-just add this inside the case
-use separate device
-or build my own and connect it to Coax input. It looks very easy

 

[noSmoking]

that's a nice rig you got going tell me what is the silver wire I can tell they run ac but what kind are they!
I will make a picture of the heatsinks I put on 7808 they are not real pretty but you can hardly feel the warm on them now I actually consider cutting them in half and let then get a little warmer,lol.

 

[jnewbold]

I don't need the USB input on a DAC. Can I simply leave off all the all parts associated with PCM2706 etc? Seems pointless to populate the board with stuff I don't need.

Joe.

 

[noSmoking]

Hi jnewbold,
Yes omit those parts and it will work fine I have one running like that .
Cya!

 

[cobretti]

here are few pics of mine

finished inside but still have some work on the case.

Also considering to add optical input (need it to connect LG LED). Found several options:

-just add this inside the case
-use separate device
-or build my own and connect it to Coax input. It looks very easy

Looks nice, I just don't understand why you running silver power wires loop all around the enclosure and back. I think you would do better if you go straight to fuses.

 

[dtses]

Looks nice, I just don't understand why you running silver power wires loop all around the enclosure and back. I think you would do better if you go straight to fuses.

well, frankly speaking that seems to me the only way to put ferrite filter inside the box Anyway, I think half of a meter of this silver mains doesn't influence on anything.

here are few more pics

 

[bartmalow]

Hi,
Anyone can advise me on transformer to be used for this dac. I have some old toroidal transformer. I presume it's about 40-50AV with secondary output voltage 2 x 15v and 2x 10v.
Do you think it would be suitable? I have also chassis mounting transformer 2x9v, 12VA. I was planning to buy 30AV 2x15v for the analogue circuit.

Cheers,