Gamma-2 (γ2) DAC Thread

[dumbears]

Today, my y2 started to make a lot of noise after playing music thru USB for sometime. However, there isn't any problem when plugging in y1 phoneout.

What is the possible cause of it? I'm thinking if it's my doing of adding a 5V transformer to y2 2 days ago. My fault was I didn't check its voltage until recently. The reading I got is 5.2V.

Pls advise. Thanks in advance.

-----------------------

I opened up the case and check all the soldering points again. Once again, I found a few ground soldering points weren't soldered properly. I wonder how I can secure all the ground soldering points. I did solder them and checked on them, but they just didn't hold well.

Any good suggestions in ground soldering? Sorry, I knew I asked this before, and I tried the suggested methods. I'm still lack of the skill to get the solder hold on the ground.

 

[xnor]

Btw, does the ASRC buffer audio and thus reduce usb audio glitches?
(spec says something about 64 samples, isn't that less than 1ms with 96kHz?)

Quote:

Originally Posted by thoppa /img/forum/go_quote.gif but I'm more interested in ...

an asynchronous diy usb dac that supports at least 24/96

(I'd prefer doing the upsampling on the computer.)

 

[thoppa]

I'll leave it to someone else to explain async upsampling....not to mention software vs hardware upsampling... not getting drawn into that....

....but I will say my y2 does support 96/24...because I'm not (yet) using the y1 as the iis source...I'm using a usb Teralink x2 which is asio and 96/24 and has iis output.... and it's a lovely combination.

 

[xnor]

Quote:

I'm using a usb Teralink x2 which is asio and 96/24 and has iis output.... and it's a lovely combination.

How would that work with USB if the product page says "no driver needed"?

 

[thoppa]

There is a driver in development, and Michael at Teradak very kindly sent it to me, so a few people here at head-fi have been testing it.

It works well with XP sp3 and Foobar, and others tell me it works with Vista and Win 7. I haven't found anyone with Win 7 64 bit and an X2 to test it yet.

I don't know the details of how the data is sent but it seems to me that iis gives better definition than spdif, but I've only tried this with the X2 and y2 so I don't know if this is a 'generally true' thing.

 

[xnor]

I see.

I've got more questions.

So with the AD8656 the y2 can also drive headphones, but is there a catch? (compared to the OPA2365)

And secondly, how well does it cope with usb latency? My laptop shows ~1ms latency spikes (measured with DPC latency checker) every now and then, that's a problem right? (Disabling wi-fi seems to help.) The rest is in the 250 - 500us range.

 

[thoppa]

I guess it's true to say there is no free lunch.......I believe from what I remember reading on the datasheets that the op will outperform the ad for things like distortion and rejecting noise and ripple on the power supply.

However, they have 'character'. From the op amp rolling I've done, AD chips often sound neutral, dynamic with a strong centre focus. BB chips seem to be more varied but are often a bit warmer and have less of a centre focus. LM chips tend to be a bit brighter and more detailed with a wider soundstage. But that's a very broad generalisation.

I think latency problems will depend on how good your PC is. But I generally first find out what size buffer will cause audible errors and then add at least 50% to that. The driver for the x2 has an auto buffer. However, if you are not doing editing and mixing, and just playing files, then I don't see why anyone would want low latency, unless they can hear a difference between buffer sizes. I can't but I haven't 'really tried'. No doubt there is a thread somewhere discussing this....with some people saying you can't, and others saying you can, and others stoking the debate...and someone saying some esoteric and ultra-expensive widget solves it....

For the y2, I just tried a Ploytech usb asio driver to work with the y1 usb module I just finished (y1 provides iis to the y2). It is a weird install, asking me to remove and re-attach the y1 several times, and delete a newer file for an older one, but it works and improves the sound quality. Unfortunately, it is far from free and costs over half the price of the x2. And I think I prefer the x2 anyway !

 

[xnor]

thoppa, I appreciate your answers but I'm more of a facts guy. And that generalization (whoever it originates from) really is stupid, imo. :/

You're mixing up things when talking about latency. I was not talking about playback latency (which doesn't matter (to me)).

Afaik, the y1 USB DAC is a PCM2707 with a sampling rate of up to 48 kHz max. Event the most exotic driver couldn't change that, right?

 

[thoppa]

Latency is a loop-back delay no ? Feel free to educate me

But maybe you should PM me....this thread is supposed to be about the y2...and we're adding noise...

 

[WyldRage]

I need some help with my gamma2 build. It didn't work at first, the voltage measures were exact, but my computers didnt recognize it when I plugged it in. The switch does turn red, with either the walwart or USB plug. After resoldering the SMDs for the third time, it actually worked ONCE, even managed to get sound out. So I put it in its enclosure, and try again an hour later: it doesn't work anymore.

I still get correct readings on voltage, but the switch is red and the computers don't recognize it. I'm uploading pictures of my build, I'm thankful for any help I can get.

Cheers,

 

[ShinyFalcon]

First thing I would do is to clean the flux off. There may be an unintended connection somewhere on the USB portion. Do you have an external optical/coaxial out device that you can test the y1's optical/coaxial in with?

 

[WyldRage]

Tried the optical, there is a slight reduction in noise, but that's all. The light still stays red.

Also gave it (another) good scrub, no dice.

 

[amb]

- Does the computer recognize it as "USB Audio DAC" when plugged into the USB port?
- Did you install the correct parts in U4D and U9D (MCP100 and MCP101, respectively)? Check the voltage at U2D pin 9 after power-up, it should be at 3.3V.

 

[mace1337]

Quote:

Originally Posted by WyldRage /img/forum/go_quote.gif I need some help with my gamma2 build. It didn't work at first, the voltage measures were exact, but my computers didnt recognize it when I plugged it in. The switch does turn red, with either the walwart or USB plug. After resoldering the SMDs for the third time, it actually worked ONCE, even managed to get sound out. So I put it in its enclosure, and try again an hour later: it doesn't work anymore. I still get correct readings on voltage, but the switch is red and the computers don't recognize it. I'm uploading pictures of my build, I'm thankful for any help I can get. Cheers, -Removed pictures-

Looking at these pictures I can see a few things:

-Clean off all flux
-Clean of all blobs of solder that don't belong, you have a few sticking to parts and to the board.
-Check the length of the leads of the through-hole parts, some of them look too long, or have a tuft of solder on them.
-Check for bridged pins with a multimeter, U1D on the Y1 for example looks like it might have some bridged pins on the picture. Check all IC's

 

[WyldRage]

My thanks for the help, I got it working (again). I just reflowed... re-soldered the SMD components, for the 3rd or 4th time.

I just hope it will work more than once this time.