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Alien DAC v1.1 Construction Thread - Page 52

post #766 of 1562
actually, fallen angel's boutique film cap application would be so much better if he had shorten the legs.

Sigh, parasitics inductance is bad
post #767 of 1562
Quote:
Originally Posted by TzeYang View Post
actually, fallen angel's boutique film cap application would be so much better if he had shorten the legs.

Sigh, parasitics inductance is bad
Considering that the interconnect cable at the other end of those coupling caps are going to be much longer than the capacitor lead, it wouldn't make much difference.

If these were power supply decoupling caps for a high speed, wideband opamp, a compensation cap or some other circuit that deals with RF, then it's a different story. It would be very important to keep the lead inductance low in those cases.
post #768 of 1562
Quote:
Originally Posted by amb View Post
Considering that the interconnect cable at the other end of those coupling caps are going to be much longer than the capacitor lead, it wouldn't make much difference.

If these were power supply decoupling caps for a high speed, wideband opamp, a compensation cap or some other circuit that deals with RF, then it's a different story. It would be very important to keep the lead inductance low in those cases.
now why didnt i thought of that

Thank you for pointing that out amb.
post #769 of 1562

Help needed for the PCM 2702 soldering.

It look like I don't have the right equipment to perform a good job for the soldering of the PCM2702, because I think I just scrapped one board...



Anyone willing to trade 3 (or maybe 4 if the damaged board can not be saved) PCM2702 to solder the PCM for me on it or make your price... I'm more interested in the design of the case then to solder this extremely tiny SMD =)

Thanks in advance,

Dark Shadow
post #770 of 1562
Minimalist enclosures for the Alien DAC ...


... using the CMoy method. There's still plenty of room for some nice bypassing film caps, too.
post #771 of 1562
Tomb,, nice work on those enclosures.

I like that someone agrees with me about those Blackgates, they're more expensive but definitely pay out!
post #772 of 1562
Quote:
Originally Posted by MASantos View Post
Tomb,, nice work on those enclosures.

I like that someone agrees with me about those Blackgates, they're more expensive but definitely pay out!
Thanks - but it's no comparison to the excellent casework you're offering on yours in your sponsored thread.

I agree that the BG's have more dynamics and detail - I just wish they had the bass of the ES's.
post #773 of 1562
Dark Shadow,

These pins #11, #12, and #13 are dangling outputs. So your PCB is till useable.
post #774 of 1562
Quote:
Originally Posted by kuohsing View Post
Dark Shadow,

These pins #11, #12, and #13 are dangling outputs. So your PCB is till useable.
Hm. The PCB does look usable, nothing that can't be cleaned up. Lots of flux and lots of desoldering braid and it should come out looking OK.

But although the pins aren't connected to anything, I don't think they should be connected to each other either. I think I noticed some weirdness with the USB not being recognised when I bridged some of those pins.
post #775 of 1562
Quote:
Originally Posted by kuohsing View Post
Dark Shadow,

These pins #11, #12, and #13 are dangling outputs. So your PCB is till useable.
Quote:
Originally Posted by Calroth View Post
Hm. The PCB does look usable, nothing that can't be cleaned up. Lots of flux and lots of desoldering braid and it should come out looking OK.

But although the pins aren't connected to anything, I don't think they should be connected to each other either. I think I noticed some weirdness with the USB not being recognised when I bridged some of those pins.
Thanks for hint...

My only problem is that I do not want to scrap them trying to solder the PCM2702...I know now that I do not have the practice and equipment to solder them... Like I said in a earlier post, I'm looking for someone that have some space time to solder the PCM on my two boards with compasation.

After that, I will solder the rest and continue to work on my case design (will be CNC machined case with LCD display, preamp and maybe I will also add a Gainclone in it to use it at work.)

Dark Shadow
post #776 of 1562
Hey guys,

I've got the weirdest thing happening with one of my AlienDACs. When I plug it into my desktop PC, I get a device not working properly error and my the USB port hub (not external, just the set of USB interfaces on the motherboard) stop responding.

The weird part is that it works perfectly on my laptop

has anybody had this kind of problems, or have any idea of what's going on?
post #777 of 1562

Oscillator Noise?

I had asked previously about a problem I am having but without any reply so I will try again. I built the Alien DAC and it works. However, there is a hum even with no USB connected and running on a battery. The hum seems to be around 60Hz, but also seems to go up in frequency with time. I am thinking that it has something to do with the oscillator. Rather than build a new board from scratch does anyone have suggestions as to where I should start? I did use a BOM that listed the ferrite arrays rather than the single ferrite SMD. Could that have caused the problem?
post #778 of 1562
Quote:
Originally Posted by lmiller View Post
I had asked previously about a problem I am having but without any reply so I will try again. I built the Alien DAC and it works. However, there is a hum even with no USB connected and running on a battery. The hum seems to be around 60Hz, but also seems to go up in frequency with time. I am thinking that it has something to do with the oscillator. Rather than build a new board from scratch does anyone have suggestions as to where I should start? I did use a BOM that listed the ferrite arrays rather than the single ferrite SMD. Could that have caused the problem?
Sounds strange, the oscillator is 12MHz. Which ferrites did you use?
post #779 of 1562
I'm not sure if this is the exact part number but it is similar to Digikey 240-2539-1-ND. In thinking back (I built the board in March), I'm not sure the ferrites could have anything to do with the problem since initially I did not install the ferrites, but simply wired across the pads for the ferrites. If I do hook the DAC to my computer, it plays music without a problem, but I get the hum/buzz along with the music. And I get the hum powering the DAC with a battery and nothing connected except the outputs to a headphone amp. Of course when the battery is removed, the hum goes away. It sounds like 60 Hz, but could be higher and the frequency seems to go up slightly over time. Something is oscillating, but I don't know where to look.
post #780 of 1562
No offense, but it sounds like you should've installed the ferrites.
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