Alien DAC v1.1 Construction Thread - Page 51

BOM Validation

Can someone have a look of my compiled BOM? I taked multiple BOM from here some some change suggested by the forum user.

Thanks in advance,

Dark Shadow

(Note that I did not check for minimum ordering numbers.)

1. 240-2539-1-ND is a FERRITE ARRAY, that means a bunch of ferrite parts in a single case - not what you need.

Use 490-1057-1-ND instead. You need 8, not 20.

2. 490-1673-1-ND - you need 10, not 20

I can't tell exactly what you're doing with the electrolytics, because some of these are combined Alien DAC part numbers, apparently, but:

7. 604-1058-ND - this should be the main power cap. A 1000uF will easily fit here, 680uF or 560uF are still good. 470uF is a minimum choice, so I would make it bigger - use P12354-ND instead. This is a 1000uF, 10V Panasonic FM cap It is only $0.50, and is just a couple of milimeters taller than the USB socket. You only need 1.

Your number 604-1058-ND appears to be an ELNA RFS. As noted above, there are better choices for the power cap, C2 - IMHO. This is a good choice for C13, however, which should have the low ESR. However, you might accomplish as much with a normal cap by upsizing. You can actually fit as much as 330uF, 6.3V - which is what I selected: P12918-ND. You only need 1. I can't take the additional time to research the actual ESR, but the point is it might be better to upsize a good quality power cap than by going boutique, IMHO.

8. 604-1054-ND is an ELNA RFS. For CL/CR, this is a great choice. However, you only need 2.

9. 604-1055-ND is also an ELNA RFS. For C23/C33 they may be overkill. These are the regulator "power" caps. A standard FM or FC might be a better choice, and you can upsize them to the same 330uF, 6.3 listed above. I kept them at 47uF on mine and have no issues. Your choice. You only need 2.

10. This should be R14. Not sure why you switched from Yageo on this one. It is 311-1.00MCRCT-ND You need 1.

12. This was supposed to be R31 at 31.2K. However, it looks like you searched since that exact value was not available, but you dropped the "K". Yageo has a 31.6K, which is the closest. Try 311-31.6KCRCT-ND, instead. You need 1.

13. This is R32, you need 1 (I am not checking for minimum ordering qty's, obviously). This resistor and R31 above are used to set the voltage at ~4.7V for the USB-powered, regulated version of the Alien DAC. Only REG101UA-A or REG102UA-A is needed if you are using these values for R31 and R32. REG101/102UA-5 is not needed.

14. This is RLED, you need 1.

17. 151-1081-ND may be a better choice. It has gold-plated contacts and is still only $1.02.

18. Despite the items below, REG101UA-3.3 or REG102UA-3.3 is mandatory for every option of the Alien DAC. You must use this chip no matter what. Your selection is fine.

19 and 20. This may indicate some confusion. You only need one - either the REG101/2UA-5 or the REG101/2UA-A. Both are used to regulate the ~5V portions of the DAC. "...UA-5" is set at 5V, period. However, since it has to burn some fractional volts to regulate, you must have a power supply greater than 5V. "...UA-A" is the adjustable version and you have selected the proper values for R31 and R32 above to make your DAC regulated-USB-powered.

So, you only need REG101UA-A (or REG102UA-A). REG101UA-5 or REG102UA-5 is not needed.


Whew! I hope this helps.

Thanks for the quick reply

Noted, I made the change.

Noted

This came from a suggestion from alf to try Elna instead of std caps.

Noted

Correction done.

I was sure that I missed to say something when I made my post yesturday night...

I planning to do two alien dac (I already got 2 pcb). One simple powered USB one, and the other to be enclosed in a CNC machined case that will have a headphone preamp in it...Maybe a PPA v2, I'm not sure yet. so in this case I think I will need a fixed regulator right? If so, what should be the value for R31 and R32?

Thanks again for your support

Dark Shadow

Skip those Yageo resistors.
Digi-key offers Vishay/Dale resistors which you do not have to buy in multiples of 10.

Yeah, mine are all V-D's as well. It looked like he was trying to stay with Yageo's for some reason, and I tailored my comments according to that theme.

Dark_Shadow - the Elna's definitely won't hurt in those other positions, just thought you might like some other options.

I have not studied or built the powered option. Maybe Mister X may help you with that.

Tom, twisting the L & R output wires together like this can lead to increased cross talk.

Also, if you want to try an experiment, there are some 0805 "Film" caps (I think they are polyester), Digikey part #PCF1126CT-ND, that you might try bypassing the Muses with. They should fit snugly between the pins ... I haven't gotten around to trying this yet. Additionally, you could also try some silver mica 0805 caps to see how they sound.

Is that right? I thought it was just the opposite. I've always done it - never noticed any problems.

EDIT: Don't people braid interconnects? This serves the same purpose, doesn't it?

Cool I like vishay, we use some vishay high precision resistor for strain evaluation at work...

Do you have any digikey part number to get me going so I can know the serie you used.

Thanks

Dark Shadow

Has anyone put an Alien DAC in the same enclosure as a DIY amp? I'm planning to build one and put it in the same case as a CK2III (amp board, transformer, DAC would all be in one case). Would this combination lead to any noise contamination?

Good thought. I already have the Sonicaps, though, will maybe try them first. As you no doubt know, the 0.22 Gen II's are not really that big - maybe like a 5W Kiwame. Still, that may not be enough considering the relative size of this thing. I'll put the ones you suggest on my next DigiKey order.

I'm not sure the BG's will ever equal the bass of these ES's. They really thump. Much thanks, of course, to your excellent reviews and trailblazing work in recommending these:
http://www.ecp.cc/cap-notes.html

Each signal should be twisted with its own return. So, ideally you'd want two ground wires -- one with each signal wire. When people braid interconnects, like the Kimber braid, there are 2 ground wires and one signal, or two grounds and 2 signals, but the signal and return are always balanced. Here, you have two signals which can interact with each other. Now, the importance of this is probably pretty minor, but with a very high end signal it can make a difference.

I appreciate your support on this project. I am, I think, about to embark on another round of tests. But, this time I have reason to try some of the best of the best caps, partly because I should be able to use smaller values than I have in the past. I am still trying to decide which ones to try, but I sold off my Cary cd player to fund building the best DAC I can.

OK - makes sense. I always want to know if I'm doing something wrong.

Can't wait to see the results of your latest work. As far as small vs. smaller, it would be nice to see some larger ones with the electrolytics. Although that could get very expensive, I suppose.

I like FallenAngel's boutique film cap application: