Author Topic: discrete dac mock up  (Read 22839 times)

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Offline yeo

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Re: discrete dac mock up
« Reply #120 on: April 18, 2012, 07:54:43 PM »
hi ck

if you want to try out your dac with the resistors, you could buy them and i'll install for you. you need to pay through your nose for those resistors though.

hi kevin

glad to hear this!

hi  kp

remember, without the buffer onboard, output impedance of the ladder is 10kohm. feeding to your ad815 with its input impedance of 10kohm... isn't going to be nice.  :)


feel free to try it though!

yeo



Offline CKL

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Re: discrete dac mock up
« Reply #121 on: April 18, 2012, 08:01:57 PM »
Hi Yeo,

Those resistors are too expensive for me!  :o

Offline kp93300

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Re: discrete dac with Xmos usb i2s converter
« Reply #122 on: May 03, 2012, 08:00:05 AM »
Hi
I manage to get the 2 to sing tonight.
The xmos is powered by usb line and a diy salas low voltage shunt at 3.5 V for the digital isolator chip  IL715.
i am using a ATOM based fanless pc with Window 7 and Foobar .
I am having a constant background  distortion that is very obvious with soft music. This is not present when the music is paused or between tracks.. This is very similiar to what i heard  with the i2s signal from QLS 550 also . However, it is much more prominent here.
 I wonder where to troubleshoot.

regards

kp93300

Offline kp93300

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Re: discrete dac with Xmos usb i2s converter
« Reply #123 on: May 03, 2012, 08:01:52 AM »
more pictures

Offline yeo

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Re: discrete dac mock up
« Reply #124 on: May 03, 2012, 02:50:09 PM »
hi kp

check for bad solder joints. especially on the xmos board since it's new.

if you have music, then the i2s wiring is correct but bad solder joint could contribute to such noise.

i once built a discrete monica which has a "whooshing" sound in the background. like there's wind blowing. turned out that there was one such bad connection.

yeo

Offline reo

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Re: discrete dac with Xmos usb i2s converter
« Reply #125 on: May 07, 2012, 04:04:13 PM »
Hi
I manage to get the 2 to sing tonight.
The xmos is powered by usb line and a diy salas low voltage shunt at 3.5 V for the digital isolator chip  IL715.
i am using a ATOM based fanless pc with Window 7 and Foobar .
I am having a constant background  distortion that is very obvious with soft music. This is not present when the music is paused or between tracks.. This is very similiar to what i heard  with the i2s signal from QLS 550 also . However, it is much more prominent here.
 I wonder where to troubleshoot.

regards

kp93300
Hi kp93300
did you manage to bring your power up to feed your digital isolator chip to 5 volts and at least .460mA and above but not more than .600mA .500mA being adequate for my WaveI/O card ., and myself use the J2 to J5 and the ground from H4 instead of using the isolated I2S output.
I have fiddled a little further and now using the master clock from the WaveI/O to connect to BuffaloII and use the Wave's clock instead therefore bypassing another stage on the BuffaloII .
I still use usbMonica2 with all her mods but  the discreet dac could be my solution for getting the best of both worlds , BuffaloII with her strong high and low end and usbMonica with her full wide mid range sound frequencies .

rolie

Offline kp93300

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Re: discrete dac mock up
« Reply #126 on: May 08, 2012, 05:02:10 PM »
Hi Rolie,
I tried your suggestions and power the isolator chip with 5V regulated from a 7805 . The 7805 is powered from a 1 amp smps regulated power supply.
The distortion is still present.
The current demand for the isolator chip is very small because the 7805 is barely warm.

I have not been using the B2 for a while after playing with the discrete monica. I will try the xmos wave io  card on the B2  some time later.
I quote -- (I have fiddled a little further and now using the master clock from the WaveI/O to connect to BuffaloII and use the Wave's clock instead therefore bypassing another stage on the BuffaloII .) . How do you do that ?

thanks

kp93300

Offline reo

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Re: discrete dac mock up
« Reply #127 on: May 09, 2012, 01:05:45 PM »
hi kp
when looking at your BII. with the twisted pears facing upright you will notice the +, and neg. pads at the R17 mark. The R17 is for bypassing the digitizer on the BII., but to disable the power that feeds that component you will remove, if you have installed the middle trident regulator which is the snap in one, the middle one . If you didn't use  the trident regulator,  disable the resistor on the underside of BII that regulates that middle power supply.

From the WaveI/O master clock signal you will  connect the line to the right R17 pad., then the  left  pad of the R17 is the return signal that goes to the negative of the Master clock., keep both signal at same length as the other signal wires from WaveI/O to BuffaloII . the shorter and of equal length your wires connections from WaveI/O to BII. are the better the signal will respond .
By doing this exercise of using the Wave card and BII it will confirm that your Wave card is faulty, or not .
Oh PS i'm not using the isolating I2S, i rather use the J2 to J5 connections from the Wave card to BuffaloII.

rolie

Offline kp93300

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Re: discrete dac mock up
« Reply #128 on: May 10, 2012, 06:57:20 PM »
Hi Rolie
Thanks for your instructions.
Your master clock signal is the MCK signal in the wave Io board ?

regards
kp93300

Offline reo

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Re: discrete dac mock up
« Reply #129 on: May 11, 2012, 03:13:41 AM »
hi kp
yes the MCK would be the J5 on the Wave board.

 Please feel free to post results that compare both dacs .

regards

rolie

Offline CKL

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Re: discrete dac mock up
« Reply #130 on: May 20, 2012, 10:32:34 PM »
This clock is a perfect match to my EVO:

Phase noise (@1kHz): -145dBC/Hz min.
Precision: +/- 1.5ppm 0°C to 50°C
Temperature stability: +/- 1ppm
Vcc stability: +/-0.3ppm

Offline cw

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Re: discrete dac mock up
« Reply #131 on: June 04, 2012, 01:08:28 AM »
@all tester,
some news from the diy dac? How, is the sounding after the test phase?
Regards ..........Carsten

Offline yeo

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Re: discrete dac mock up
« Reply #132 on: June 04, 2012, 02:22:24 AM »
hi carsten

i have been selling discreet monica since i put up the article. however there is a backlog now so i'm having a hard time to cope. hey, it takes me one whole day to build one so i wished i could speed things up.

email me if interested.

i'm only selling built up version like the one you see on the article. all aluminium chassis with toroidal transformer. about sgd2000 depending on input options. for now i offer spdif input but may offer usb input later.

yeo

Offline Rinaldo

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Re: discrete dac mock up
« Reply #133 on: June 18, 2012, 07:28:56 AM »
Hello CKL,

I do as well own a Hiface EVO and I am considering an EVO Clock that would reclock both the Evo and my Studer D730 CD Player.
Unfortunetaly I wouldn't be able to reclock my DAC (a MSB TEch Platinum DAC III) as the clocking interface is f......g proprietary.  :-\

Could you tell us a little more about the improvements you have been experiencing with the external clock against no external clock ?

Jean-Paul.

Offline CKL

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Re: discrete dac mock up
« Reply #134 on: June 18, 2012, 05:01:13 PM »
Hi JP,

With the clock, the sound has become more natural. Without the clock, the sound is more hifi. So I can't say the clock has made a big improvement. May be I am using Eneloop 9V battery to power the EVO making the little difference.

Clock is troublesome as you may not know it is compatible with your DAC without buying it. Still, the EVO clock is not very expensive comparing with many others.