Wolfson WM8740 DIR9001 PCM2706 DIY DAC

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Hi,

recently I've found one interesting diy DAC kit based on Wolfsons. I had previously FMJ DV27 from Arcam using Wolfsons WM8740, was pretty happy with the stage and resolution. Any suggestions regarding this one?:rolleyes:

Already found 3 dedicated transformers home that could be used with it, however couldn't find any decent chassis, does anybody have one or know the place where it could be bought?
 

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I will be interested to hear the comparison of this to a DV27 as I know the person who designed the DV27. The DV27 uses a 4 layer PCB and this PCB is 2 layers. The layout on this PCB doesn't look great as the ground plane is very segmented. However looking at a PCB is a poor predictor of how well it will work from an audio point of view.

I can tell you that this PCB will probably would not pass EMC regulations but since it is a kit it doesn't need to.

I hope it works out well. If not I have some ideas on how you might be able to improve it.

Regards,
Andrew
 
hi Andrew,

thanks for the comments. The most simple way of improving this diy dac I have already found - change opams to some decent ones like LM4562, for instance.

it's really interesting whether this dac could be at least close to DV27, however the last one isn't a benchmark too, just an old good DVD player with separate psu and famous WM8740. So I guess if I use this kit with good transport it shouldn't be far from DV27 at least theoretically :)

Some time ago I had Arcam's CD23, that was something. Not sure that any DIY kit could get close to dcs's dac...

ac2010
sure I will, just need some time to get the kit from China and assemble all the stuff.
 
received the kit today :)

pcb looks to be very decent and pleasant to work with. Components are the following:
-Nippon ASF 3300uf psu
-Panasonic FJ 1500uf psu
-FC, Cerafine, BC 036
-don't know the brand of film caps, though hope they are of good quality

the scheme (pls se att) looks quite simple. Any ideas of improvement except good opams, for instance, LME49710, separate transformers for 9-0, 9-0, 15-0-15v:rolleyes:
 

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I also have this kit. Elna electrolytic capacitors seem to be fake, Nichicon Muse (100M/25V) seems genuine. I am not sure about ON Semi 7808 stabilizers, those seem to be fake too. I will definitely pick up another stabilizers and all caps. PCB layout is not clear, no labeling on some parts, rear side has a lot of misprints. The count of parts doesn't correspond to PCB layout. What I see at glance, this kit will be a headache to put together.
 
well, not sure about these fake Elnas, could be just some old series.

all labels present on my pcb, btw already have assembled it and could post few photos later. Found that few caps and resistors were surplus and three resistors 1k5 were missing, though it's not a big point as I suggest.
 
Can you possibly qualify this statement with a photo, or a reason for this comment? I am curious to know about Elna fakes. I didn't realise there were Elna fakes. Thanks.
I had fake motorola transistors before, also Duracell NiMh batteries, ON semi stabilizers, those are already in dumpster. You can read net throughout about forging semiconductors and other parts in China.
 

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MC7808, here you go. I could quite easily separate the back side just by my fingers. No tools. All parts look suspicious to me. Lets believe Chinese don't have enough know how and technology to counterfeit DACs like WM8740 for now.
 

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finished mine, works perfectly! Unfortunately don't have any CD player currently with digital output to compare this DAC with my good old heavily moded Philips CD350.

btw, tried to to separate back of my rectifiers and could affirm that it's quite difficult only by the fingers. Anyway, I've changed them to be safe :)

will post some pics once get a camera.
 
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