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Old 5th May 2011, 07:47 AM   #31
awpagan is offline awpagan  Australia
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Quote:
Originally Posted by dtses View Post
cheers cobretti!

seems to me that it's a cap in the output stage, pls see att. Not sure what is the purpose of it, but maybe someone could explain.
Lookup RC circuits
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it's probably a polyprophylene or cheaper ceramic
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Old 5th May 2011, 11:42 PM   #32
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Quote:
Originally Posted by awpagan View Post
Lookup RC circuits
RC circuit - Wikipedia, the free encyclopedia

it's probably a polyprophylene or cheaper ceramic
Never seen a cap with such color coding.
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Old 6th May 2011, 12:28 AM   #33
erin is offline erin  Australia
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check out the comment on capacitors....
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Old 12th May 2011, 07:50 AM   #34
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cheers!

finally found and ordered chassis for the dac. It's not the best you can find, though bearing in mind dac's price I suggest it's ok. Moreover front plate could be replaced with some thick black glass for instance. Inside is enough place for pcb and three transformers.

Also ordered new genuine FCs and Silmics to replace all caps and be 100% sure of decent parts used there.

One question makes me feel uncertain. Could anyone pls explain me what is the purpose of quartz here (near the usb) and could it be replace with external clock as further upgrade?! As far as I know in CD players quartz/ clock determines the speed of a disc or some other stuff too?!

Last edited by dtses; 12th May 2011 at 07:55 AM.
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Old 12th May 2011, 08:56 PM   #35
gfiandy is offline gfiandy  United Kingdom
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I think that cap is a EMC filter cap to reduce hf noise on the output cable.
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Old 12th May 2011, 10:04 PM   #36
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Quote:
Originally Posted by gfiandy View Post
I think that cap is a EMC filter cap to reduce hf noise on the output cable.
Please don't take it the wrong way but I still don't understand. What kind of purpose is it suppose to serve? If that should be a low pass filter the cut off frequency is 15.9MHz (I hope I calculated it right). From my point of view it's not supposed to be there at all. But I might be wrong. regards
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Old 13th May 2011, 08:43 AM   #37
cyteen is offline cyteen  England
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The 12Mhz crystal on the front edge is used by the PCM2706 you could try this.

The other crystal I can't make out but presume that it is for the dac, If you had a low jitter clock you would be better off using it here than for the pcm2706.
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Old 13th May 2011, 04:29 PM   #38
gfiandy is offline gfiandy  United Kingdom
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It is intended to reduce the radiation of the clock and it's harmonics onto the cable which would form a good antenna to radiate the noise.
This is very common practice in electronic equipment.
A clock typically has significant energy upto it's fith harmonic so a 12MHz clock will have energy upto at least 60MHz.
Regards Andrew
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Old 23rd May 2011, 09:13 PM   #39
jackies is offline jackies  United States
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Any more comments on the sound? I'm tempted to order one...
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Old 24th May 2011, 09:50 AM   #40
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I'm on a way to change all psu caps to FCs and 10uf, 47uf to genuine Elnas, at least to be 100% sure that I'm getting maximum from the parts. Swapped diodes to fast Schottky ones.

Also finishing adjusting the case that turned up to be very good for price paid 30 USD (incl. European delivery)
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