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Old 25th March 2013, 03:57 PM   #281
Coris is offline Coris  Norway
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The caps and the resistor too have to be removed, before connect in place an oscillator. Or cut out the two traces which it goes to XI/XO.
The processor pins XI and XO are XtalIN and XtalOUT of an internal circuit which it resonate with the original quartz. That original clock component is an resonator, but not an oscillator. When is to connect an oscillator, the internal circuit it function completely different.
The oscillator OUT pin it have to be connected to the XI pin (input clock pin) of the processor, and the XO have to be open. Does not work (right) to connect the oscillator OUT to the XO pin. That because all the old components around that original quartz it have to be removed, to have an normal function of that clock circuit inside the processor.
Having the resistor in place one connect actually the IN pin and OUT pin together and mess that circuit when is to apply the clock coming from an oscillator. Heaving the caps in place (one or both) the oscillator signal goes to GND, or its output level decrease so that it is not enough to activate the internal clock circuits as it should. This means malfunction, and all the rest problems with the audio signal...

Doing right this mod it have to work from very beginning. One not have to struggle so much with the quality of the signals, noises and so on. The general improvement of audio signal is obviously right after connecting an oscillator in that place (in the right way)...

Last edited by Coris; 25th March 2013 at 04:08 PM.
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Old 25th March 2013, 04:00 PM   #282
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Quote:
Originally Posted by Corvus5 View Post
The quality is too good. I'm upgrading my headphones as it is hard to notice any big difference from upgrading the xonar card.

The caps are floting in the space - the ground was destroyed along with the quartz pads. They are not being used and the clock is soldered betweend XTALI and its cap. The resistor is however stil present. Changing clock placement is something I don't want to do.
If the caps are out of ckt, then what you have is fine. The resistor STAYS (it was not removed in either tutorial I noted earlier).

As far as you headphone out... Upgrading headphones themselves is a good idea. The Xonar's headphone ckt. is not worth modding IMO. If you want to DIY headphone ckts, look at separate amp projects at places like Tangentsoft.net, amb.org or HeadWize.
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Old 25th March 2013, 04:11 PM   #283
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Quote:
Originally Posted by Coris View Post
The caps and the resistor too have to be removed, before connect in place an oscillator
Not the resistor, just the two caps. This is per both the manual instructions I prev. mentioned.
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Old 25th March 2013, 10:44 PM   #284
Coris is offline Coris  Norway
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What is the role/function of that resistor?
What "manual instruction" is that?
How do you know that what is there is right?
Have you done this mod yourself so with that resistor in place and it is working well for you?
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Old 26th March 2013, 02:56 AM   #285
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Default Answers

Quote:
Originally Posted by Coris View Post
[1]What is the role/function of that resistor?
[2]What "manual instruction" is that?
[3]How do you know that what is there is right?
[4]Have you done this mod yourself so with that resistor in place and it is working well for you?
Answers:
[1] Not sure. I've often seen this topology before on decoder chips like the AV100. Methinks it may be some sort of feedback (X_o to X_i on the AV100) important internally for the decoder DSP. Or the X_o may be linked to other chips on the PCB...and that R "damps" the signal ??? Perhaps others reading this can comment.
[2] The instruction (installation) manuals are by two separate aftermarket XO clock manufs.: LCAudio and Tent
[3] I don't. But two separate XO manuf. -- LCAudio and Tent -- specifically note that it should be left alone. So the R stays, for stock X1 crystal-only , as well as osc. (XO) such as the Vanguard many of us are upgrading to.
[4] Many times. Mostly in CDPs, but also in certain outboard D/As. That said, I've never experimented with removing it after upgrading from xtal to osc. (XO). If the osc. XO works for you with this R removed, and the graph looks clean and the sound is unaffected or even improved, I can't explain that.

Question for Coris/others:
Why remove the R if upgrading from simple (two-terminal) xtal to (4-terminal) osc. clock?
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Last edited by hollowman; 26th March 2013 at 03:15 AM.
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Old 26th March 2013, 04:29 AM   #286
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For a possible answer to [1], check out the diagram in the first post of this thread I created back in early Jan. Look at the patent schema figure at the end. For this TCXO, note component 3 (R ?) "feedback-buffers" inverter logic. But if one removes the 5a and 5b (caps), R3 is effectively opened.
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Last edited by hollowman; 26th March 2013 at 04:33 AM.
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Old 27th March 2013, 09:53 AM   #287
Corvus5 is offline Corvus5  Poland
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Take a look at the measurements I took today. I usualy had 100nF, I removed it and the sound was awful. Added tantalum, still fresh. The difference is measurable.
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File Type: png G36 - THD comparison 2.png (30.1 KB, 113 views)
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Old 27th March 2013, 03:52 PM   #288
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Default Which cap are you talking about?

Quote:
Originally Posted by Corvus5 View Post
Take a look at the measurements I took today. I usualy had 100nF, I removed it and the sound was awful. Added tantalum, still fresh. The difference is measurable.
Which cap are you talking about?

Some reg. designs use BOTH (small and large value) caps per their datasheet suggestions (if the above is for LM7805, are you using datasheet suggestions?). Parallel the two and listen/measure. Or try the default 0.33uF per Fairchild PDF.
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Last edited by hollowman; 27th March 2013 at 04:12 PM.
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Old 27th March 2013, 09:08 PM   #289
Coris is offline Coris  Norway
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I come again with some (better/right) measurements...
I have generated (Audition old/new) the signals (see pictures): -2dB, 192Khz sampling, 32bit. ASIO 32bit/1ms is used to play out the signal. Picture 9 have an -3dB signal. Oscilloscope coupled directly (10:1) to the RCA output on one channel. I assume that another one have similar parameters...
That`s it! Looks good, looks bad, is another story. It sounds just wonderful (much, much better than an original card) and this is important at last...
(Maybe I will do something about the HF noise to lower that at the output... As one can see, the output Vpp level is all the time the same, no matter the frequency which goes through... )
Attached Images
File Type: jpg no signal.jpg (212.2 KB, 100 views)
File Type: jpg HFnoise.jpg (257.5 KB, 97 views)
File Type: jpg 1.jpg (272.8 KB, 91 views)
File Type: jpg 2.jpg (270.1 KB, 21 views)
File Type: jpg 3.jpg (242.0 KB, 16 views)
File Type: jpg 4.jpg (232.0 KB, 18 views)
File Type: jpg 5.jpg (250.4 KB, 18 views)
File Type: jpg 6.jpg (257.7 KB, 17 views)
File Type: jpg 7.jpg (254.4 KB, 15 views)
File Type: jpg 8.jpg (262.7 KB, 16 views)

Last edited by Coris; 27th March 2013 at 09:24 PM.
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Old 27th March 2013, 09:09 PM   #290
Coris is offline Coris  Norway
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...the last ones...
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File Type: jpg 10.jpg (273.5 KB, 22 views)
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