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Twisted Pear Audio Opus DAC
Jul 13, 2008 at 8:11 PM Post #706 of 994
Okay, you guys have swayed me to pick up the metronome too.
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Quote:

Originally Posted by akione
My personal preference is for the IVY rather than Ballsie.
I find it sounds smoother and more seductive.
The Ballsie sounds more 'Hi-Fi' to me, although both are excellent.


I've seen similiar comments. I've already ordered the Ballsie though, so, I just hope the Opus/Ballsie/Metro couples well w/the SE Beta22 I built. In any event I think it will be a step or two (maybe more I hope) above the Zhaolu I have.

It's good to know a 2" high case will work. I didn't want to go beyond that unless I had to.

Thanks guys.
 
Jul 13, 2008 at 9:15 PM Post #708 of 994
I am thinking about making my USB receiver module into a portable DAC and casing it in a Hammond 1455C802. What would be the best way to connect it to the Opus from the portable case? SPDIF? or I2S? If I use I2S would I jumper DO to DI and have both analog and digital available at the same time, or should I use a switch to put it in SPDIF, thereby making the analog outs available? I guess the connections would be easier with SPDIF because it would be a simpler connector and not require a switch, but would it introduce more jitter or other distortion than I2S?

Scott
 
Jul 15, 2008 at 7:40 PM Post #709 of 994
I would use S/PDIF. It was designed for inter-component communication. I2S was not; it *can* be done, but is going to be a lot trickier.

I have one in a Hammond case in front of me, but with no outputs. I built one a while back for my brother with a headphone jack on the front and stereo RCA jacks on the rear (either side of the USB jack), so adding an S/PDIF jack on the back would be pretty simple.

For mine, I used the shorter case (1455C801), which is slightly too short for the USB board. I just chopped the very end of the USB module off on the chop saw (could score and snap with a utility knife). If you cut it to the exact length of the case, it leaves the USB jack mounting points and allows a nice overhang of the jack that will stick through the rear panel.

The only other issue is the height of the included SILMIK caps, but you could swap them out for something smaller.
 
Jul 15, 2008 at 7:58 PM Post #710 of 994
Quote:

Originally Posted by BrianDonegan /img/forum/go_quote.gif
I would use S/PDIF. It was designed for inter-component communication. I2S was not; it *can* be done, but is going to be a lot trickier.

Let me dig up some pictures if I can find them...


I was thinking the same thing about SPDIF, but then started thinking (very dangerous) about somehow docking the portable dac to the Opus. Maybe use a mini din connector with some physical docking mechanism. I don't really need to do this since I ordered another usb module and can have one inside the Opus and one portable, but I just thought it would differentiate my build from all the others.

Scott
 
Jul 15, 2008 at 8:01 PM Post #712 of 994
A potentially good solution to both problems would be to use S/PDIF and transmit the clock as well. You still need the S/PDIF receiver though.

I2S is a bit more difficult and unwieldy, but should work okay over short distances (2-3 feet at most). CAT5 gets you 4 tight tolerance twisted pairs, easy to get connectors and cables, and just happens to be the right number of conductors for I2S.
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. Using them with differential signaling would help a lot for some distance (and require transceivers), but it does work over short distances. A signal transformer might help too if crosstalk becomes a problem. Put a signal and ground on each pair, should work fine with nothing fancy for a couple feet.

Edit re your last post: I think it's a good idea! Not crazy at all. Should be quite trivial to get working too if you go the S/PDIF route.
 
Jul 15, 2008 at 9:07 PM Post #713 of 994
Funny you should mention CAT5...I was also thinking that a RJ45 jack might be another good way to connect the usb module to the main dac. I was even thinking about cutting a large hole in the front panel of the main dac where the whole usb module would be inserted, then the RJ45 would be engaged when the module is fully inserted. I would just leave enough of the usb module sticking out the front to be able to get a grip to extract the it.
The distance from the usb module to the boards inside would only be about 3 inches, so I2S might still be an option. I would try the usb powered Opus as well, but I will also be using other receiver boards and a balsie, so I will need power for when I forget my usb dac at work.
OK, sounds like I have a plan...if it doesn't work, I'll just build it with a dedicated usb module.

Scott
 
Jul 17, 2008 at 12:41 AM Post #716 of 994
Quote:

Originally Posted by alxwang /img/forum/go_quote.gif
Does anyone know where I can find a build instruction so I can know how difficult to build it? Thanks


There is information on Twisted Pear Audio. Check there first, then ask here if you need more input.
 
Jul 26, 2008 at 2:54 AM Post #719 of 994
A quick question about the IVY: I just finished building my ver 2.0 kit and I don't have caps C13-C16. Looking at the board traces, they look like filtering caps, but I just want to be sure they're the optional filtering caps and not a required component that I'm missing. I want to start with an unfiltered configuration, so should I just leave C13-16 open?

Also: The electrolytic caps that come with the Opus, those are coupling caps if you run the Opus in SE w/out an output stage (I will jumper them since I'm using the IVY) right?
Thanks.
 
Jul 26, 2008 at 2:58 AM Post #720 of 994
Quote:

Originally Posted by dgbiker1 /img/forum/go_quote.gif
so should I just leave C13-16 open?
Thanks.


Yes, leave them open.
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There is a IVY manual written, and it should be up on the site soon.

Those caps are only used for a hybrid configuration for the Buffalo DAC.

In most cases they should left open.

Cheers!
Russ
 
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