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'noodle' dac (ebay special)

post #1 of 180
8/17/08 at 4:40pm
Thread Starter 
I wanted to build a cheap dac for my father to use between his airport express and hifi.

I bought this from ebay for £30 delivered:


Spdif / toslink in, Digital / Analog converters: CS4397 24bit 192khz DAC Digital receiver : Crystal CS8416

currently house in a cardboard box (but is going in a hifi2000 case).

FOR THE MONEY: This sounds seriously good standard. Drop an opa2107 (poor mans 627) in it and it sounds brilliant. Nice rich sound, darkish but detailed. Organic highs. I doubt this will compete with your stello or benchmark, but i wouldnt be suprised if it caught a few people out.

Nest step? get shot of the coupling caps and replace with a nice film cap. Replace the electrolytics with something better like pana FC's.

In comparison with my alien dac? Its more natural, more body to male vocals, seems to have more slam and generally sounds 'bigger / more bodied'. I wont say its better, because i use my alien for portability, and this is clearly not portable - they serve different functions. However, on my home rig currently this is getting all the air time.

when i remove the stock coupling caps and replace with something like an auricap or claritycap i suspect it will move to new level.
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post #2 of 180
8/17/08 at 5:04pm
I was looking at that kit but chose the Alien as I want a USB input....
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post #3 of 180
8/17/08 at 5:05pm
Thread Starter 
gurusan - where in oxford? I live in oxford. what have you built.
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post #4 of 180
8/17/08 at 5:10pm
Just happened to look in this thread and:
You guys too? I'm here as well. All my builds are barely off the ground though...
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post #5 of 180
8/17/08 at 5:29pm
I live in North Oxford...not built anything yet..I'm a noob!



have an alien DAC kit on the way though along with a Little Dot 2 and HD 595 cans ...this is my first proper setup after a few years of a XFI which I modded and HD 205s

Do you know if there's any way to add a USB input to that ebay special DAC?
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post #6 of 180
8/17/08 at 5:48pm
Thread Starter 
you could get a cheap usb to spdif and do it that way. but you would then have two conversions, and a lot of the cheaper usb converters dont get good reviews.
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post #7 of 180
8/17/08 at 6:01pm
Thread Starter 
actually, looking at the datasheet you could build a usb > I2s converter (search these boards) and maybe try. Anyone know if this would work.

Connect serial data to sdata pin
Connect bit clock to sclk pin
Connect word select to lrclk pin
connect ground to s ground pin
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post #8 of 180
8/17/08 at 8:49pm
Please tell me that was a kit and that somebody isn't just selling DACs on eBay in cardboard boxes
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post #9 of 180
8/18/08 at 3:55am
Thread Starter 
A kit.... but you have to admit, the box looks 'tight'.
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post #10 of 180
8/18/08 at 5:09am
I bought ine recently. I've only had a few hours listening, but it seems pretty god. I have it connected to the SPDIF out directly out of my PC (with a DIY SPDIF adapter), and it still sounds pretty good. It is very revealing.

I've jus bought a HagUSB to simplify the connection. It will be intereting to compare the current SPDIF with the USB.

And, of course, the price of these units is definitely right
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post #11 of 180
8/18/08 at 5:28am
Blue tack, you serious?

















Looks great though =)
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post #12 of 180
8/18/08 at 6:20am
Thread Starter 
yes! bluetak damps and vibration and improves the optical transmission. I use it in all my builds. Cocopops provide the bext casing material, they really improve the 'pop' and 'crackle' the dac puts out. Due to the lack of cocopops housing matieal i went for the next best thing, 'nicky clarke travel hair dryer'. Whilst not in the same league as the breakfast cereal, it does provide a nice 'warm but dry', you could almost say 'airey' sound.

Just ordered my modushop (hifi 2000) cases. 1 for the dac and one for a bijou amp that i will build next.
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post #13 of 180
8/18/08 at 2:42pm
Thread Starter 
ok, serious question now.

I found this for a potential mod



basically all coupling caps bypassed and thentwo better coupling caps in place. Seems very sensible.

However, the chap recommends 3 to 10 uf film caps. Are these not too big? surely the impedance this thing is going to see is the 50k pot in my amp? most preamps will have this order of this sort of impedance - thus wont i need something around 0.47uf???
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post #14 of 180
8/18/08 at 5:03pm
Yep, you're right.

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post #15 of 180
8/25/08 at 12:55pm

Questions...

OK, so I've bought one of these and want to tweak it.

I've replaced the op-amp with an OPA2132PA (the only dual op-amp I had lying around) which is a noticeable improvement over the stock one, but intend to get an LM4562NA (data sheet here: LM4562 - Dual High Performance, High Fidelity Audio Operational Amplifier ) unless anyone knows any good reason not to.

In the photo Adamus posted a couple of posts ago, the coupling caps have been removed and replaced with links, but there appear to be lots of other changes too. I'm I right in thinking I only need to remove the 6 electrolytics that I've indicated in the photo below, replace with links and add a 0.47uF film cap plus a series resistor to each channel's ouput?



How do I decide what value of resistor to use? The dac will be connected to my Starving Student which has a 50k pot and also to my Arcam amp which has an input impedance of 22k ohms?
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