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Old 7th October 2012, 04:49 PM   #131
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I have just received the last version PCB and I have some difficult to find all parts, because there are some differences from schematic to PCB and BOM. So I have some questions for Quanghao and all guys that built the DAC:

- which 74HC04 package, SOP or SOIC?
- I cannot find any switch suitable for P2, Mouser or Digi-Key part?
- at the upper right corner of the PCB there is a kind of transistor foot print, marked XLR IN, what is rhat?
- in the pictures published from Quanghao and other guys, SPDIF transformer is not fitted. Is it not needed for coaxial input?
- in DAC shunt regulator schematic and BOM I found 6 2K2 resistors (R5, R14,...). Where are them on the PCB?
- I found 6 10K resistors in shunt regulator BOM, but I cannot found them in schematic and PCB?!?!
- in PCB shunt regulator I found 6 diodes (D21...D26), but I cannot found them in schematic and BOM. What are them?
- in the pictures published I can see some capacitor (100 nf???) at each output of the shunt regulators, but I cannot found them in schematic and BOM. What are them?
- what Mouser or Digi-Key part for IRF heatsink?
- I have to choise output tubes, what do you suggest, 5687/E182CC/6DJ8/6922 or 6H30PI?

Thanks all for any help

Andrea
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Old 10th October 2012, 07:21 PM   #132
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Anyone can help me?
thanks
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Old 10th October 2012, 07:35 PM   #133
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[QUOTE=andrea_mori;3192885]I have just received the last version PCB and I have some difficult to find all parts, because there are some differences from schematic to PCB and BOM. So I have some questions for Quanghao and all guys that built the DAC:

- which 74HC04 package, SOP or SOIC?

74hc04 , can fin in ebay

- I cannot find any switch suitable for P2, Mouser or Digi-Key part

- at the upper right corner of the PCB there is a kind of transistor foot print, marked XLR IN, what is rhat?
Not use XLR in

- in the pictures published from Quanghao and other guys, SPDIF transformer is not fitted. Is it not needed for coaxial input?

Yes, only use Cap in put

- in DAC shunt regulator schematic and BOM I found 6 2K2 resistors (R5, R14,...). Where are them on the PCB?

change by zenner diode 2.7V

- I found 6 10K resistors in shunt regulator BOM, but I cannot found them in schematic and PCB?!?!
se in the pcb

- in PCB shunt regulator I found 6 diodes (D21...D26), but I cannot found them in schematic and BOM. What are them?

- in the pictures published I can see some capacitor (100 nf???) at each output of the shunt regulators, but I cannot found them in schematic and BOM. What are them?

- what Mouser or Digi-Key part for IRF heatsink?

- I have to choise output tubes, what do you suggest, 5687/E182CC/6DJ8/6922 or 6H30PI?

5687 or e182cc

thanks
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Old 10th October 2012, 07:43 PM   #134
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Quote:
Originally Posted by andrea_mori View Post
Anyone can help me?
thanks
Please see this file !
thanks
Attached Files
File Type: zip Bom DAC.zip (11.9 KB, 86 views)
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Last edited by quanghao; 10th October 2012 at 07:46 PM.
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Old 12th October 2012, 10:58 AM   #135
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Quote:
Originally Posted by quanghao View Post
Please see this file !
thanks
Hi quanghao,

I would like you reply to all my questions, because I have difficult to find some parts, because in some case is not clear what specific part are needed.
For example:
- 74HC04, I can also find it at mouser, but I asked which package, SOP or SOIC? Have you designed PCB for SOP or SOIC footprint?
- slide switch P2: you have designed PCB for a specific footprint, please let us know what specific Mouser or Digi-Key part fit correctly onto the PCB.
- about SPDIF transformer you said to use caps only, do I need some wire link on PCB instead of transformer?
- about 6 * 2K2 resistors you said to replace them with 2.7V zener, are them the diodes marked D21...D26 on the pcb?
- about capacitors at the output of each shunt regulator I've seen in some pitcures, but I can't find in the schematic and in BOM, what are them?
- again, you designed DAC PCB to use specific heatsink for IRF540/9540, I have difficult to find a suitable heatsink, please let us know what specific Mouser or Digi-Key part fit correctly onto the PCB
- the last schematic is not aligned to PCB and BOM (either DAC PCB than IV PCB), please publish the correct schematic

Thanks
Andrea
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Old 13th October 2012, 10:56 AM   #136
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Hi Guys, for Stage 4 1660 board Lundahl lists a ll1660 and ll1660s. Would one be better than the other? Would they both work?

I see Quanghao used the 10 MA version, there is also an 18ma version. Does it make a difference if I use one of the other. .

http://www.lundahl.se/pdfs/datash/1660.pdf
http://www.lundahl.se/pdfs/datash/1660s.pdf

These are the two fact sheets from Lundahl. Any recommendations/thoughts appreciated.
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Old 15th October 2012, 05:20 PM   #137
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Anybody for my question on the Lundahl ll 1660 or 1660s? Does it matter which one I use?
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Old 15th October 2012, 06:00 PM   #138
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Quote:
Originally Posted by JohnGeneva View Post
Anybody for my question on the Lundahl ll 1660 or 1660s? Does it matter which one I use?
I believe higher rating would be fine but lower could cause the core to saturate faster. Not 100% sure on that one though...

Do
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Old 16th October 2012, 03:14 AM   #139
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[QUOTE=JohnGeneva;
Not worry about it. I make paralle for ll1660, you can choise Ll1660 18ma, or 10 ma.
Thank
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Old 16th October 2012, 03:21 AM   #140
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[QUOTE=andrea_mori

No correct, but i post all next some day later .thank
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