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y1 gamma-1 DAC - Page 51

post #751 of 1535
7/11/09 at 4:59pm
I don't get the same results for the transmitter, says Obsolete and wont let me put it into the cart.

EDIT: I sent an email asking for the status on these Toshiba parts.
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post #752 of 1535
7/11/09 at 5:30pm
digger945, TOTX147PL is obsolete. The only viable source at this time is Farnell, who still has stock. The next revision of the y1 PCB will support the Sharp GP1FMV31TK0F, which is also out of stock at Digikey, and they told me that the lead-time is 15 weeks.

EDIT: Or, you could use this transmitter:
http://www.sysconcept.ca/product_inf...roducts_id=159
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post #753 of 1535
7/12/09 at 2:13pm
One more question. Was anyone able to use the optical out of y1 under mac in pass through mode? That is , to pass the sound through the y1 so that a dts enabled dac can decode the audio?

I've been trying with VLC and Cog but still I cannot force DTS music to go out of y1.


Any suggestions?
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post #754 of 1535
7/12/09 at 5:08pm
There is no "pass through" mode on the y1. The S/PDIF outputs (config C or F) are only active for USB input, and the PCM2707 receiver chip does not handle non-PCM audio streams.
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post #755 of 1535
7/14/09 at 1:12am
Hey Ti,
I'm planning on building a full version of the gamma 1 for the gamma 2 proto phase. Since I don't really need the optical input, can I just skip installing it and just use the coax input for S/PDIF? If so, is there anything else I can omit from the circuit ?
There seems to be a general consensus that there is no real avantage for one (coax) vs the other (optical) or vice versa from a SQ perspective.

I'm still having a debate with myself over whether I should get one anyway, just for completeness sake (say, for resale at some point).

JD
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post #756 of 1535
7/14/09 at 1:25am
Quote:
Originally Posted by amb View Post
digger945, TOTX147PL is obsolete. The only viable source at this time is Farnell, who still has stock. The next revision of the y1 PCB will support the Sharp GP1FMV31TK0F, which is also out of stock at Digikey, and they told me that the lead-time is 15 weeks.

EDIT: Or, you could use this transmitter:
Sys Concept Inc. Fiber Optic Products Attenuators, Patch cords, Laser Diodes, Connectors, MP3, Toslink, Hybrid Adapter and more: 16Mbps Optical Transmitter (Toslink)
Will the next revision still support the TOTX147 also?
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post #757 of 1535
7/14/09 at 1:27am
MrSlim, yes you can omit the TORX147PL (and L1D and C12D) if you don't want optical input. I would also install a wire jumper between the TORX147PL's output pad and GND pad.

As for advantage of coax vs. optical, the popular opinion is that (properly implemented) coax is better, but having both input types give you the maximum flexibility with difference sources, and lets you connect one of each type (and USB too) and switch between them.
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post #758 of 1535
7/14/09 at 1:28am
Quote:
Originally Posted by funch View Post
Will the next revision still support the TOTX147 also?
Yes.
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post #759 of 1535
7/14/09 at 6:20pm
Quote:
Originally Posted by amb View Post
MrSlim, yes you can omit the TORX147PL (and L1D and C12D) if you don't want optical input. I would also install a wire jumper between the TORX147PL's output pad and GND pad.

As for advantage of coax vs. optical, the popular opinion is that (properly implemented) coax is better, but having both input types give you the maximum flexibility with difference sources, and lets you connect one of each type (and USB too) and switch between them.
Great, thanks Ti..
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post #760 of 1535
7/15/09 at 10:00am
I just placed an order for my TOTX147PL with Newark. The $20 handling fee only applies (in the US, anyways) if you're having them drop-shipped direct from Toshiba. Else, there is no handling charge - just a one week lead time.

I bought 5 of these as well, if anyone doesn't want the headache/wait, I'll let 3 of them go for the cost of shipping.
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post #761 of 1535
7/15/09 at 1:34pm
Please clarify the "Reset" circuit formed by U4D, U9D, and the integrator R8D, and C21D. It appears that the integrator is used for the delay, from U4D to hold "Enable" low while U4D provides VCC to U9D to place the DAC in "high performance" mode then turn "de-emphasis" OFF. I know this is over simplified.
The data sheets give the info about holding enable low until the DAC is powered up, and setting the DAC to high performance mode, and the info about de-emphasis. Data sheets also give info about the 150 ms delays of the MPC100/101. My question is about the timing between U4D, U9D, and the integrator.
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post #762 of 1535
7/15/09 at 1:55pm
Quote:
Originally Posted by m_Lowry View Post
Please clarify the "Reset" circuit formed by U4D, U9D, and the integrator R8D, and C21D. It appears that the integrator is used for the delay, from U4D to hold "Enable" low while U4D provides VCC to U9D to place the DAC in "high performance" mode then turn "de-emphasis" OFF. I know this is over simplified.
Yes, this is correct.

Quote:
The data sheets give the info about holding enable low until the DAC is powered up, and setting the DAC to high performance mode, and the info about de-emphasis. Data sheets also give info about the 150 ms delays of the MPC100/101. My question is about the timing between U4D, U9D, and the integrator.
See the timing below, as captured on my scope. Horizontal scale is 100mS/div, vertical scale is 1V/div.
- The yellow trace is the input 5V rail, showing the rising edge as the power is applied.
- The cyan trace shows the output of U4D reset manager going high to 3.3V after approximately 250mS, enabling the CS8416 S/PDIF receiver/mux.
- The violet trace shows the U9D reset manager going high at the same time as U4D, but going low after 250mS delay. This appears at the DEEMPH pin of the WM8501 DAC.
- The green trace is after the R8D/C21D RC delay, into the WM8501's ENABLE pin. You can see that the WM8501 gets enabled while its DEEMPH is held high to activate high-performance mode, and then DEEMPH is set low by U9D to turn off de-emphasis.

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post #763 of 1535
7/15/09 at 2:03pm
Quote:
Originally Posted by jh0n View Post
I just placed an order for my TOTX147PL with Newark. The $20 handling fee only applies (in the US, anyways) if you're having them drop-shipped direct from Toshiba. Else, there is no handling charge - just a one week lead time.

I bought 5 of these as well, if anyone doesn't want the headache/wait, I'll let 3 of them go for the cost of shipping.
I'll take one, and YGPM.
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post #764 of 1535
7/15/09 at 3:47pm
Thanks, Ti. The capture of your scope, with your explanation, is exactly what I needed to clarify the operation. I had actually forgot about the reset of the CS8416.
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post #765 of 1535
7/15/09 at 4:24pm
Has anyone compared the SQ of the y1 when using USB power vs a high quality 5V dedicated power supply(or not so hight quality, ala wallwart)?

I expect this may become more apparent when the y1 is coupled with the y2...
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