Gamma-2 (γ2) DAC Thread

[Beefy]

I had that sound going through my head as I posted......

Quote:

Originally Posted by mace1337 /img/forum/go_quote.gif

 

[amb]

Quote:

Originally Posted by simwells /img/forum/go_quote.gif Just looking at ordering the necessary parts to build my Gamma-2 now, but was wondering if there was a paticular reason the recommended capacitors for the multilayer ceramic capacitor X7R 1µF 25V were these; EPCOS|B37984M5105K|CAPACITOR, 1UF, 50V | Farnell United Kingdom

The preferred part is actually TDK FK24 series for their low profile, but Farnell does not carry this line. The Epcos is still acceptable at 7.5mm high. Any higher and the cap will start to bump into parts on the other side when the two boards are plugged in to each other.

Quote:

These add up to a lot when I add the neccesary number, was wondering if there was a cheaper but equally good alternative available? Something like this maybe? VISHAY BC COMPONENTS|K105M20X7RF53H5|Ceramic Multilayer Capacitor | Farnell United Kingdom

This one is listed as "US Stock". Since you're in the UK, you'll have to pay an extra £15.95 fee...

 

[simwells]

Ah missed that, well I think I'll order everything but those caps and the other couple of bits not stocked through farnell via farnell anyway.

 

[mace1337]

Quote:

Originally Posted by simwells /img/forum/go_quote.gif Ah missed that, well I think I'll order everything but those caps and the other couple of bits not stocked through farnell via farnell anyway.

I mentioned this last page, but mouser carries a lot of the parts and all orders of 75€ or over are free shipping. Digikey has free shipping over 60ish.

My parts for the M3 I built were here in three days from both mouser and Digi-key.

Also, I'm not sure why you're going for 1uF when the parts list mentions 0.1uF, which should be significantly cheaper.

 

[jarpatus]

Quote:

Originally Posted by mace1337 /img/forum/go_quote.gif Mouser has a pretty good selection though, they have the Nichicons ES, KW, FW and all that, and they deliver anywhere in the world for free if your order is over 75€

Thanks mace1337, I totally missed free delivery and did not consider mouser because I tought I will have to pay extra (local in town suppliers can order from Farnell without extra fees but not from Mouser or other overseas-only company).

It looks I am forced to build another y2 so I can order missing part(s) from Mouser within the same order 8) Is it against spirit of DIY if I'll make few extra DAC's and try to sell them and gain little profit?

 

[fierce_freak]

I got my y2 done yesterday but I'm getting no sound. When measuring voltages I get the proper 3.3v and 4.5v, but in the places indicated that should be 5v I'm only getting ~4.66v. Does that point to anything in particular? I'm going to go back over my soldering for the WM8741 and the SRC4192 when I get some spare time.

 

[amb]

Quote:

Originally Posted by fierce_freak /img/forum/go_quote.gif I got my y2 done yesterday but I'm getting no sound. When measuring voltages I get the proper 3.3v and 4.5v, but in the places indicated that should be 5v I'm only getting ~4.66v.

If this is USB power, then it probably just means that your computer's USB "5V" is a little low, but not low enough to make things "not work".

You have to be a bit more specific than "no sound". What other testing have you done? Does the companion γ1 work (i.e., you hear audio from the WM8501 output via the front jack)?
Have you verified the polarity/orientation/value of all parts and their solder joints? All jumpers set properly for the configuration and options you're building? etc...

 

[fierce_freak]

Yep, the y1 portion works properly (I hear audio from the WM8501 output via the front jack). Polarity/orientation/value has all been checked. I'm almost willing to bet it's my soldering of the WM8741 and SRC4192. I just hope I can fix it without ruining another board and having to start over. I have a bad habit of lifting pads.

 

[amb]

There is little risk of lifting pads if all you're doing is reflowing the joints. Use plenty of liquid flux, only a tiny amount of solder, and avoid too much heat. If your X1 oscillator is the SMD version, then reflow its joints too.

 

[rille2]

I read here about alternatives for U7. But this was in a quite early state of the project. Could I use the LME49721? OPA2365 and AD8656ARZ are hard to get at the moment in Europe. The LME49721 is available. Are there any other alternatives?

 

[amb]

We never tested with LME49721, so I don't have any actual bench or sonic experience to share on this opamp. Based on the datasheet specs, it has enough supply voltage range and rail-to-rail swing capability to do the job. However some other specs are not as good as those of AD8656 and OPA2365, and its 9mA maximum output current also falls far short.

A quick search of Farnell Germany shows both OPA2365AID and AD8565ARZ currently in stock...

 

[GWorlDofSPACE]

Quote:

Originally Posted by amb /img/forum/go_quote.gif We never tested with LME49721, so I don't have any actual bench or sonic experience to share on this opamp. Based on the datasheet specs, it has enough supply voltage range and rail-to-rail swing capability to do the job. However some other specs are not as good as those of AD8656 and OPA2365, and its 9mA maximum output current also falls far short. A quick search of Farnell Germany shows both OPA2365AID and AD8565ARZ currently in stock...

I have AD8565 installed and do not use Y2 direct whit my headphones, so
does it make any difference to switch to OPA2365???

 

[amb]

Quote:

Originally Posted by GWorlDofSPACE /img/forum/go_quote.gif I have AD8565 installed and do not use Y2 direct whit my headphones, so does it make any difference to switch to OPA2365???

They are both excellent, just slightly different in sonic character. Don't bother changing it unless you enjoy desoldering an SMD opamp (and risk board damage).

 

[GWorlDofSPACE]

Quote:

Originally Posted by amb /img/forum/go_quote.gif They are both excellent, just slightly different in sonic character. Don't bother changing it unless you enjoy desoldering an SMD opamp (and risk board damage).

I had some issues whit SMD X1, so I DO not enjoy SMD!
Thanks.

 

[MisterX]

Would be a major pain with all of those other parts in the way.