My latest project - DAC + headphone amp

[Ryssen]

I also have AVR ISP programmer. I just happen to pick it up for future AVR Adventures

Can you do the programing for me/us would be stubid if I buy this card and can´t use it.

 

[Sylvania]

Hi

Link to a simple AVR programmer:

http://www.myplace.nu/avr/yaap/index.htm

connector and 5 resistors works...

Best regards Kim Olesen

 

[Geek]

Hi Gmarsh,

Do you have a closeup picture/scan of the top of the PCB's available?

 

[Geek]

The blank (unpopulated) PCB's?

Also, someone asked for schematics and stuff. My Guru made these from Eagle layouts:

Schematic
Topsilk

 

[Geek]

Moderation: Please delete above two posts of mine.

 

[rjkdivin]

AVR Programming

gmarsh,

I got myself an AVR ISP MKII programmer, and have downloaded the ATMEGA8L datasheet and ATMEL Pers Comp Program, but I am very new to this........are there some helpful hints as to what programming is required, or some specific code you can provide?

Any further help would be greatly appreciated.

I know we don't even have boards yet, but I'm getting ready!

Robert

 

[Ryssen]

Sounds good,too rely on you for programming.

 

[gmarsh]

Re: AVR Programming

gmarsh,

I got myself an AVR ISP MKII programmer, and have downloaded the ATMEGA8L datasheet and ATMEL Pers Comp Program, but I am very new to this........are there some helpful hints as to what programming is required, or some specific code you can provide?

Any further help would be greatly appreciated.

I know we don't even have boards yet, but I'm getting ready!

Robert

Attached is the most recent Mega8L code for the DAC - .hex file ready to program, C source file and makefile. It's the same as the previous code except L/R aren't swapped anymore.

To recompile, you'll need WinAVR - http://winavr.sourceforge.net/

Set the Mega8L fuses/flags for a 4MHz IntRC oscillator when you program.

(edit: file is actually attached now)

 

[matjans]

hey guys,

sorry about not getting back to you for the group buy. I've been too busy lately with my last exams and preparations for my final thesis.

Unfortunately my studies take up so much of my time I have to pull out. That, and the fact that i'm *totally* broke (which is normal for a student, i suppose). Sorry 'bout that.

I wish all of you good luck building & listening! Maybe if there's going be a second run i'll step in again. I've been dying for a good headphone amp. I'll have to do with the good 'ol m-audio audiophile usb for now. Good thing foobar finally has a decent asio output plugin.

Matt

 

[kct]

Hi,

I am new here and came across this project thread while searching for a nice headphone amp with digital in. This is exactly what I was looking for. Thanks to gmarsh for sharing this great project with the general public. This is awsome.

So I guess I missed the boat for a PCB, if someone still has an extra one I like to buy it. Or if another group buy comes up, please count me in for a PCB.

Cheers

Kay

 

[Ryssen]

http://www.diyaudio.com/forums/showthread.php?s=&postid=1089081#post1089081
Merry X mas!

 

[kct]

Hi,

I was wondering if there would be any interest to a slight modification/addition. I really
like to have an optical output so this unit could be looped through an optical path.

I hope one can get away without having to buffer the output of the optical RX for the
TX. The optical TX and support caps could be omitted and not be populated if one
would not want this option.


I checked into a GB with PCB Pool, as per there online quote 10 pcs.
4 layer 160 x 100 mm board would be about $ 220 US

Please see picture.

An externally hosted image should be here but it was not working when we last tested it.

 

[kct]

Posted again, with changes I propose.


Changes summary:

- added option for Optical Out with Buffer IC and decoupling Caps.
- moved power configuration to make room for it
- moved fuse holder slighly
- moved Regulator components IC U11, C47, C22 to get clearance for installation in case
- repositioned Crystal and C34
- added option for LED1, R33 (I like to see if the unit is powered)
- put a trace underneath the D/A chip, 0 Ohm R28 can be omitted then
- and changed Label to HD-1.1 to up-rev it.

These proposed changes are of course open for discussion.

I hope the option for the optical out finds interest.

An externally hosted image should be here but it was not working when we last tested it.

 

[Algar_emi]

Hi gmarsh. I'm in the process of updating with the current prices and completing the parts list. So far I have a few questions:

The processor is not available:ATMEGA8L-8AI, Part OBSOLETE
can you suggest a compatible replacement?

I cannot see these parts:
MLCC, 2.2uF, 25V, X5R, 0805, cannot see them on the schematic
C1: 0.022uF, not in the part list
C2: 1000pf, not in the part list

Thanks in advance.

 

[Algar_emi]

Here the updated parts list. It is for the original Eagle PCB design.
gmarsh there is resistors marked TBD. I guest they are "To Be Determined". Can you give me these parts values.

Thanks...

 

[Algar_emi]

Line Output option

Just asking if this circuit can do the trick. I'm not asking to have this inlcuded on the PCB, but I may try to had by myself a small home made SMD pcb with these parts, mounted on the back of the PCB. I tried to used as many standard parts as possible (same parts used on the stock PCB).

Let me know if the circuit can work and if my parts values make sense. Just one channel is shown.

Thanks in advance..

SB

 

[alladinboy]

ATmega8L obsolete

ATmega88 is not assigned to replace ATmega8 (Atmel say), but is pin compatible and have large Ucc capabilities (you don't need 'L' voltage versions like ATmega8L). I have built (in another DAC construction, just for test) with ATmega88 and work fine. But take care - ATmega88 hat a lot of differences in registry names and IN/OUT instructions.

 

[suds]

Can I make PCB for this ?

Hi,

Can I make PCB for This Project ?

I can post estimated cost once I get go ahead from author,
and latest gerber files, is any changes are done.

-suds

 

[kct]

Hi Suds,

see this thread:

http://www.diyaudio.com/forums/showthread.php?postid=1513092#post1513092

Cheers

 

[Space489]

Does anyone know very simple DAC DIY project? I need high quality DAC with volume control for SPDIF rca from PC to my active speakers. Speakers input resistance is 10k ohm.