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y1 gamma-1 DAC - Page 47

post #691 of 1537
5/28/09 at 8:16pm
Quote:
Originally Posted by amb View Post
jamess71, you must be confused because Jeff does not supply a kit for the γ1.
Anyway, the only parts worth experimenting with are the output coupling caps. Opinions vary on those, so changing them might only be a "sidegrade" rather than an upgrade.
Thanks Amb. I was confused, the last kit I got from Jeff was the Bijou. ;-) I have Elna RFS, caps in there now, I'll leave em be. Thanks again for an Awesome dac and design.
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post #692 of 1537
5/28/09 at 11:39pm
Quote:
Originally Posted by amb View Post
Wiatrob, try reflowing the solder joint at the WM8501's left channel output pin.
Joint looked good but I reflowed anyway. Good connection from top of pin to C26 -- Bad WM8501?
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post #693 of 1537
5/29/09 at 2:15am
Wiatrob, if you've ruled out a bad connection, then the only possibility left is the WM8501 itself.
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post #694 of 1537
6/5/09 at 10:25pm
Thanks,Ti, I'll report back on the fix soon...
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post #695 of 1537
6/6/09 at 12:53am
So guise, I was being a klutz and I forgot to order a piece of X1U for the USB board.

I don't think it's wise for me to get it online again (shipping fee sucks) just for that part alone so which of the following is a good substitute for the X1U? (just pick the best alternative out of these options)

AVX HC49SF 12MHz 12pF
AVX|HC49SFWB12000H0PESZZ|CRYSTAL, HC-49, 12MHZ | Farnell Malaysia
EUROQUARTZ 12MHz 18pF
EUROQUARTZ|12.000MHZ HC49/4H/30/50/40/18PF/ATF|CRYSTAL, THT, 12.000MHZ | Farnell Malaysia
IQD FREQUENCY LF A158K 12MHz 30pF
IQD FREQUENCY PRODUCTS|LF A158K|CRYSTAL, 12MHZ | Farnell Malaysia
AKER 12MHz 18pF
AKER|CA-12.000-18-3050-X|CRYSTAL, HC49/US, THT, 12.000MHZ | Farnell Malaysia
CITIZEN AMERICA 12MHz 18pF
CITIZEN AMERICA|HC49US12.000MABJ-UB|CRYSTAL, 12M, 18PF CL, HC49/4H | Farnell Malaysia

I don't know much about digital circuits but it seems to me that the first option seems to be the best one to get as an alternative. Will I suffer any loss in performance by using any of the options above?

Thank You!
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post #696 of 1537
6/6/09 at 1:20am
The spec'ed crystal is 20pF with temperature stability of 30ppm, so whichever is closest to that would work best. That said, I could simply send you one if you don't mind the wait. PM me for details.
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post #697 of 1537
6/6/09 at 2:32am
thanks amb. I sent you a PM about it.
This is a gift intended for a friend before he leaves the country for australia.
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post #698 of 1537
6/8/09 at 8:33am
great work on updating the website
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post #699 of 1537
6/8/09 at 8:42am
Is it possible to install 2x phono jacks in the area marked pink below? I don't suppose you know off the top of your head what's the recommended distance off the bottom?

Also, what program do you use to draw your dimension diags? I was going to mock something up to double check
LL
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post #700 of 1537
6/8/09 at 5:48pm
I hope this drawing will be of some use for you:



If you wanted vertical clearance, I'm not sure. What do these phono jacks look like?
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post #701 of 1537
6/8/09 at 6:32pm
Quote:
Originally Posted by individual6891 View Post
Is it possible to install 2x phono jacks in the area marked pink below? I don't suppose you know off the top of your head what's the recommended distance off the bottom?
This depends on what jacks you have in mind.

Quote:
Also, what program do you use to draw your dimension diags?
I printed from Front Panel Designer into a PDF printer (file), then on Linux, captured the image from adobe reader into a PPM file using xgrasc, then did all the drawing in xpaint, and saved as a PNG file.
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post #702 of 1537
6/11/09 at 10:00am
Is there a difference in output quality between the lite and the full version when using USB?
I noticed that the AMB site states that in lite config the USB board outputs I²S and in full config it outputs S/PDIF.
So in full config the digital to analog is done by the better chip?
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post #703 of 1537
6/11/09 at 10:27am
Quote:
Originally Posted by king.mark View Post
Is there a difference in output quality between the lite and the full version when using USB?
Not really, at least none that I could measure or hear.

Quote:
I noticed that the AMB site states that in lite config the USB board outputs I²S and in full config it outputs S/PDIF.
So in full config the digital to analog is done by the better chip?
In both configurations, the D/A conversion is done by the Wolfson WM8501 chip.

In the lite config, the path looks like this (bold face denotes chip, italic denotes data format):

USB -> PCM2707 -> I2S -> WM8501 -> analog out

In the full config it looks like this:

(When the input selector switch is set to "USB")
USB -> PCM2707 -> S/PDIF -> CS8416 -> I2S -> WM8501 -> analog out

(When the input selector switch is set to "Coaxial")
coax -> pulse transformer -> S/PDIF -> CS8416 -> I2S -> WM8501 -> analog out

(When the input selector switch is set to "Optical")
optical -> TORX147PL -> S/PDIF -> CS8416 -> I2S -> WM8501 -> analog out

The CS8416 chip serves as an input receiver that allows you to select between three S/PDIF sources (switch operated), that's why in the full config the PCM2707 chip needs to output S/PDIF. The CS8416 outputs I2S to the WM8501 DAC.
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post #704 of 1537
6/11/09 at 10:53am
Quote:
Originally Posted by king.mark View Post
Is there a difference in output quality between the lite and the full version when using USB?
I noticed that the AMB site states that in lite config the USB board outputs I²S and in full config it outputs S/PDIF.
So in full config the digital to analog is done by the better chip?
With USB Audio, it is generally believed that "direct to I2S" is a better solution than S/PDIF conversion, however in the case of the Gamma 1, the "lite" configuration skips the clock recovery step that the CS8416 chip provides.
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post #705 of 1537
6/11/09 at 11:00am
Any reviews yet?
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