Building an Audio Note DAC Kit

Audio Note DAC 2.1 Kit - Some Serious Digital to Analog Conversion!

This kit belongs to a friend who is serious about his musical quality, and I've volunteered to do the build.

So... just what the hell is a DAC anyway, and why would you need an expensive bit of kit like this, when you already have a DAC built into your CD player by those nice people at the factory that made it in the first place?? And you've read that right, if you own a CD player, you actually already have a DAC in your house! You audiophile you!

Well the basics are:

CD's store music in bits - that is 1's and 0's.
Your CD player will read the CD and send those 1's and 0's to the built in DAC.
Your built in DAC will then convert those 1's and 0's to an analog music signal.
Your DAC will then pass that music signal along to be amplified a little before sending it off to your main amp.

Needless to say, when you are serious about your music, this is a critical process that needs to be done very well in order for enjoyable, fatigue free sound.

Most CD player manufacturers, in an effort to keep that shiny CD player at a price cheap enough to sell to the masses, will make some "price" compromises when it comes to the Digital-to-Analog conversion and amplification process, relying on basic DAC converter chipset's and less than adequate signal amplification stages. These DAC's and amps also share the same power supply as that of the CD mechanism, which itself is very demanding on power because of the constant feedback movements involved in the read-back process, meaning there may be less than stable power being supplied to the DAC circuit.

Solution: Buy something like this and bypass those little cheap & nasty built in circuits!

Nuts in the audio world call it the "two-box" alternative. The first "box" being a CD player that has had it's internal DAC bypassed (or a dedicated CD transport) which will just spit out 1's and 0's via a optical or coax digital connection. The second "box" of course is something like this kit - a dedicated DAC that converts the digital signal into an analog one and using a high quality internal signal amp, produces the line-level output that can be fed into a main amplifier.

Most dedicated CD players will have a digital output on them as well as the analog output. If you connect the digital output of your CD player to a DAC then you will bypass the CD player's "internal DAC" (digital-to-analog portion of your CD player) and the external DAC will then be responsible for the conversion process.

Enough of the boring stuff - Let's get into it!.

	Here's the kit as it comes out of the box - very well packed, wrapped and protected. We have the rear and front face plates, the build manual, the kit itself, and an audio test CD, a music CD and a CD with electronic copies of the manual and schematics... Nice.
	Ripping the bubble wrap off reveals a solid chassis stuffed with more packing material... weighs a damn tonne, so wonder what's inside here, must be more than foam!
	Popped the lid off the chassis and foam and component bags start tumbling out. This thing was extremely well packed for transport!
	Get rid of all that packing material and all the goodies appear. Multiple packs of PCB's and wires, components, hardware, a small choke and a very nice & decent transformer! If there was ever a time for me to get nervous as the "builder" of this expensive little kit, it was now. Looking at all those components, all those expensive caps and valves and circuitry, thinking of how many ways this could go pear-shaped... But then, hell, over the past few years I've built two chip amps, a studio series pre-amp, numerous little Altronics kits, two sets of speakers and installed a set of HID lights on the STi (with no instructions!) and have had no major fcuk ups so I must be doing something right! Time to get started - click on the pic for a higher res view.
	Don't know what this is, so just started soldering wires onto it to make it look important... Just kidding - have wired the tranfo for 240V operation. Hope that's the voltage over in Singapore where you are Chris!
	Tranfo, choke and power fittings all installed in the chassis.
	Power supply hardware all wired in and ready to go. Too easy.
	Now, this looks more complicated... The "M2 Power Supply" board. My first experience with a kit that contains valves - 3 of them across the middle of the picture there. Some very nice caps being the Jensen and Audio Note one (the two biggest caps down the bottom left) and a whole heaps of resistors, diodes and others. Click on the pic for a higher res view.
	First things first - I know the manual states to put the valve bases in first, but I always do my resistors first. I follow a general rule of installing the smallest components first, working up to the largest components. After the resistors came the valve bases, then the diodes.
	Finished board with all components in place.
	Next was the wiring and the regulators. This is the board all completed and ready to go into the chassis. Click on the pic for a higher res view.
	Regulator heatsink in place and all power inter-connect wiring done. At this point I had the power fuse in and had completed the "non-power" tests with the multi-meter. All good and all readings within the specs. I suppose the next step is to plug it in, cross the fingers and turn the power on!
	One sure fire way to find out if you've followed the instructions properly... trail by fire! Plugged in and powered on, and can't tell you how magical it was to see those two valves light up! Especially when the house-mate was hovering wondering aloud just how big a bang some of those nice big caps would make if I'd stuffed it up! Joy! Grabbed the multi-meter, flat battery (damn thing) so borrowed the house-mates multi-meter and all power on tests came back within spec. Double joy!! Click on the pic for a higher res view.
	Squint and you can just see two specs of light which are the valves a-glowing. The little canon point and shoot I use for the quick and easy shots just wasn't up to the task of capturing the vales in all their glory... Time to break out the serious equipment.
	Nikon D50 + Tripod = Sweet picture!! Look at them little buggers glowing away there - is a real pity all the valves in this kit are hidden away behind the chassis, but one of the sayings in golf, "drive for the show, but putt for the dough" applies here as well. Yes the valves glow, but that's only as a consequence of their operation, it's what they do to the music that matters! Click on the pic for a higher res view.
	Close up of the board. Click on the pic for a higher res view.
	Well, back to the build. Here's the digital power supply board all constructed and wired up ready for insertion into the chassis. No valves on this one, but some nice Black Gate caps and some LED's to make up for it!
	Digital power supply in, wired up and powered on. Outputs on the pads all as expected so going along well.
Welcome to Part II
	View of the 6922 board components. Component count is actually pretty low (but oh what lovely components they are!) so should be a nice quick build for this one.
	All in and done - too easy. Got those big Audio Note caps strapped in there. Hate to have one of them come loose and rattle around the box... would cause some real damage!
	Under side of the board - valve pins wired and the fiddly little cap/resistor combos across R3 and R8 in place.
	Close up of the board. Click on the pic for a higher res view.
	Got the board in place and wired into the power supply. As always, the fiddly wiring and buggering around took longer to do than it did to build the board. I hate inter-wiring!
	Next board to build is the USB board that was optioned with this kit. Small board, lots of little parts, just know this one will be fiddly to do.
	Some time later... USB board all done.
	Checking for position in the case with the digital board in place alongside. Next step was wiring the digital power supply across to supply the digital board. My tip for the next builder out there is to solder in the power supply side of this wiring BEFORE you bolt the board to the chassis. If there's one thing I hate, it's having to pull boards on and off the case to do a few fiddly bits of wiring...
	Now, did I already mention that I hate having to pull boards on and off the case to do a few fiddly bits of wiring... Right. So. Next tip. Solder in the signal leads to the 6922 board before plonking that one in place as well. There is no way in hell that you will solder these into place (with any form of confidence of doing it right) once the board has been bolted down.
	Installing the IV transformers is really the last major step of the build. Only a few bits of inter-connect wiring left over once these are done. One small problem I had here was that the assembly instructions note to use the aluminum spacers with the plastics "holders" to essentially lift the IV's up, and then the wiring stem face downward... You can see here that I've totally ignored that - for two good reasons. 1. When on the spacers, the moldings on the holders was at the exact same height as the PCB's and was overhanging on the boards, pushing down on them. Didn't fit in other words. 2. Wires facing down definitely meant have to pull boards out yet again to do soldering!
	So here we have the IV's in and wired up without having to pull boards out. Used a bit of shrink wrap around the wires to keep it all nice and neat. Click on the pic for a higher res view.
	Onwards to the last few bits of wiring. Installing the link, ground and signal wire between the USB board and the digital signal board. Still one last resistor to go in here on the R36 slot.
	Now, did I already mention that I hate having to pull boards on and off the case to do a few fiddly bits of wiring... Right. So. Next tip. Trying to get the coax lead soldered into the digital signal board was damn impossible while it was in place. The pads for the leads already had solder on them and could not get a fix that I was confident with, and really wanted to put the leads through the board. Bloody solder wouldn't come off using my solder wick, couldn't get the lead through while the solder was there... Pull the bloody digital board out, and off course the USB board and IV's had to go with it because short wiring is tidy, but it also leaves limited flexibility. Still couldn't get the solder out, had to resort to pulling the pin-vice out of the toolbox to drill the pads out so I could get the leads through. So... solder the coax lead in place earlier than I did!
	All done... all boards in place, all the inter-connect wiring done and chassis hardware all in place and set to go. Click on the pic for a higher res view.
	Love this board... just a thing of simplistic beauty.
	Damned coax lead!
	My usual testing routine for stereo equipment building... plug the dang thing in and see if there's any smoke! :) Again, was magical when all those lovely valves started glowing. Still using the little Canon here so you might just make out the glow of the valves. Click on the pic for a higher res view.
	Time to pull the Nikon out for a better pic. Click on the pic for a higher res view.
	Oh yeah... that's nice! Click on the pic for a higher res view.
	Shiny, shiny, bling, bling!!! This thing really needs a perspex cover for the top to let all those shiny electrons free to at least dazzle all those non-audiophiles out there who won't see the sense in an expensive DAC but will at least say how pretty it looks! Now, lets just hope it's not all glow and has some go... Time to break out the supplied audio test CD! Click on the pic for a higher res view.
	It Lives! Just grabbed what I had free to do the music test. Dug my old Sony Amp out, matched that with the Dali Concepts and feed the DAC using the Cambridge CD player. I tell you what - am impressed with the DAC as it made the Sony sound a lot better than I remembered, and am sure once the system gets a few more hours in, it will only get better and better. Click on the pic for a higher res view.
	Time to test out the USB input. Grabbed the laptop and plugged the USB cable across and Windoze XP immediately detected and installed a new "USB Audio DAC" piece of hardware... as opposed to freezing up or crashing as Windoze is prone to when presented with new hardware! Best bit - no drivers required. Just plugged it in and away it went. Apologies for the pic.
	This is what it install as under the device manager.
	To send the digital signal out to the DAC you will need to head in and edit your default sound playback device to the new USB Audio Dac device.
	Laptop all plugged in, running iTunes playing some COG through the DAC. Personally, anyone that would buy and use a DAC 2.1 to playback MP3's or similar would, IMHO require a good slap to the head! Playing compressed source material through something like this is just an insult! Whack a CD into the computer and play that, or better still, buy yourself a bloody good transport and do the Audio Note kit some justice. Click on the pic for a higher res view.
To wrap up: Just a few final notes. If you buy and build one of these kits, a) I'm jealous, and b) enjoy. My experience with the kit was extremely positive aside from some of the final inter-wiring issues. The kit itself is of fantastic quality, all parts and components are superb quality and the build process is, for any experienced builder, pretty much fool-proof. The supplied instructions were very good, and the real bonus is the care and labeling that has gone into the packaging and markings on the packages. Was nothing better than grabbing a pack, with the component value/s and board positions labeled on the outside and knowing straight away what they were, and where they went. Not much work for the multi-meter during the process, except to confirm voltage outputs during testing stages. If I had to build another - there would be some wiring I would do on the boards as I was building them. Definetly the series of power output wires on the digital power supply, the signal out leads on the 6922 board and that damn coax lead on the digital signal board. Also make sure you place the link and the resistor related to the USB conections on the digital signal board before that one goes into place as well.
Updates! Chris has taken posession of his new toy and has been very impressed with the performance once plugged into his sytem over in Singapore. But, as always with us Audio Nuts, enough is never enough and some experimentation was decided on in an effort to optimise the sound. Chris has sent me over his tale, so will hand over to Chris: Chris's tale of of Tragedy & Triumph... Bazza you legend! (Chris insisted this stay in the tale despite my modesty!) System setup: - Shunyata Hydra 8 - Leben CX300 - Apple macbook transporter - Audionote DAC 2.1 signature - Cardass neutral reference - Whatmough P33 signature So there I was, rubbing my hands in glee, after lugging the weighty DAC in-out of international airports. Should be a simple, unplug the Cambridge AV amp (with an internal DAC), and plug in the Audio Note DAC…right? Well, did all that was needed, systems hooked up, i-tunes setup playing (lossless format) through the USB output. Turned up volume to see if there were any hums…nope, no hums. Good. A few crackle & pops. Brought the volume back to 9 o'clock position. Lined up my audio testing tracks. The violin theme drifts along….hmm…things sounded better…but for some reason also unbalanced?? Not much sound coming out of the right speaker! Is it the DAC? PANIC! Did something happened during the flight?? Quickly swapped cables, changed balance R&L…still the same. Even brought back the Cambridge AV…still the same! phew* Not the DAC! It's the amp (Leben CX300). Promptly visited the shop for a check up on the amp! Swapped a few tubes, still the same also! Definitely broken! A few days later picked the amp again, sans the recalcitrant resistors. Let's try another listening test… - The frequency coverage has increased. Bottom range has more body (whilst not sounding fat & flat), and top range has also provided lower harmonics (eg: cymbals are more realistic). - The natural decays of each instruments and voice become apparent. It's just… natural. - Staging has also changed, to the extent that I needed to re-position the speakers as I was losing the bass. Very interesting, I'd be keen to understand why this is the case. So, it's been about a week. I'm still revisiting my album collections and discovering new nuances in the recordings. Highly recommended upgrade! Audio testing tracks: 1. Bach Concerto for 2 violins in D Minor BWV 1043, Largo Ma Non Tanto (Itzhak Perlman & Pinchas Zukerman) 2. More than this. Nora Jones, Charlie Hunter. 3. Nanu, Chucho Valdes 4. When Your Mind's Made Up, Glen Hansard & Marketa Irglova. Once soundtrak. 5. Into the Trees (Serenetti Part 3), Trentemoller 6. Blue Rondo A La Turk, Dave Brubeck 7. Bach: St Matthew Passion, BWV 244 - Choral Jesu, Was Hast Du Verbrochen. Anthony Rolfe Johnson, Barbara Bonney Did I mention Bazza is a legend? Bazza you legend! Geeze, thanks mate, hope you enjoy the DAC for a long time to come!
	The system... Chris, take the dang protective plastic sheet off the front of the DAC!
	The DAC in it's new home with the Valve Amp in the background.
	The valve amp...
	The DAC again...