On the ODAC, and Recent Reviews

Okay, this post is in reply to our full email inbox this morning. Regarding NwAvGuy’s upcoming ODAC:

  • JDS Labs is an official distributor of the ODAC
  • An ODAC preorder page is live
  • ODAC production began late last week in the USA, and will take about 4 weeks (release = May 2012)
  • NwAvGuy has not released specific information yet; we have little more information than what’s already revealed in his blog [Edit 4/18/2012: Now Released]
  • ODAC absolutely requires a headphone amplifier for proper operation

I know many of you are looking forward to installing ODAC in your O2’s, or having it retrofitted at our factory. (For those new to this project, three wires from ODAC must be soldered to input jack terminals P1 on the Objective2, a couple traces must be cut, and the 2x9V batteries must be removed.) A retrofit is a nightmare of a design choice for us. Sorry, NwAvGUy! Soldering one DAC is no big deal for a do-it-yourself’er, but we’re faced with soldering hundreds. And that means hundreds of our past O2 customers might want to send their amps in for the upgrade. Cost for the O2+ODAC retrofit will be announced after ODAC is released. But we’ve devised a far more elegant solution.

Option 1: Standalone ODAC in Enclosure

NwAvGuy equipped ODAC with an optional 3.5mm line-output jack, for use with other headphone amps. It just so happens that ODAC fits into the same custom aluminum enclosure we built for c421. Nick sketched new end-plates, and voila:

This is only a preview! We’ve printed prototypes and tested fit. Design files are now under review by our machine shop, so things could change based on manufacturability.

Placing ODAC in a standalone enclosure means:

  • Objective2 owners can add an ODAC without modifying their perfectly good amp
  • All features of the O2 are retained (no need to remove 9V batteries)
  • Standalone ODACs can be paired with any headphone amp!
  • Same performance as coupled to the O2

This standalone ODAC edition will be added to the preorder page as soon production begins–any day now. Available approximately upon release of ODAC.

Option 2: O2+ODAC Combo

As NwAvGuy plans, we’ll offer ODAC preinstalled in new O2’s, which will look something like this:

These will also appear on our preorder page after production begins. Available approximately upon release of ODAC.

Option 3: O2+ODAC Retrofit/Upgrade

Identical to option 2, but for those who already own an Objective2. Available in late May.

Option 4: Assembled ODAC PCB

Consists only of an assembled ODAC circuit board–no amplifier or enclosure. This is the only offering on our preorder page for now. Ships mid May.


As you can see from the above images, the ODAC product lineup is well underway. All prices and preorder options will be available by the end of May.

A Note on Reviews

The first time I browsed to Headfonia.com, I couldn’t imagine seeing our products on Mike’s awesome review site. It was all high-end gear, way beyond anything we’d built at the time. So I was surprised when Mike e-mailed me for a cMoyBB sample in early 2011. The review went well.

Note: We are not a Headfonia sponsor. In fact, we don’t sponsor or endorse any audio publications. I’d rather see our great products spread through the audio community by word of mouth, and use cash-flow instead to increase product development and distribution.

Headfonia Review - Flyin’ High: JDSLabs C421

Anyway, Mike posted a well received review of our c421 last month, with the OPA2227. But he was quite opposed to the AD8620, totally contradicting my opinion.

Then came the controversial Objective2 review, which led to a follow-up article from NwAvGuy.

I’m not taking sides. I fully endorse NwAvGuy’s work and his rebuttal, and I’ve always been a fan of Headfonia.

I personally prefer to listen to c421 with bass boost on, with DT-880’s. I have nothing bad to say about the Objective2. It’s a technically brilliant amp. But I’m a bass boost guy. Hence, cMoyBB.

The fact is, audio is subjective. NwAvGuy can post measurements and discuss psychological theory all day long, but we’re humans. Our brains operate subjectively (“expectation bias”, as NwAvGuy wrote).

Case in point, Nick says O2 and c421 sound the same. But Nick isn’t an audiophile and doesn’t spend his free time reading audio forums and reviews. He just knows that JDS Labs sells nice headphone amps.

I don’t intend to discredit Mike or Headfonia. There’s a lot of truth to what NwAvGuy writes, especially in regards to expectation bias. Mike e-mailed us after the O2 review went live; I replied explaining that I wasn’t disappointed. He expresses his honest opinion in his reviews. NwAvGuy blogs about objective audio engineering. JDS Labs has to tie everything together. We build amps that we believe in, both in terms of design, and in terms of taste/expectation bias. We receive dozens of emails each week asking for comparison of one amp to another. While I could steer a customer one way or another, I sincerely avoid replying in depth to any of these messages.

Read reviews and blogs. Read specifications. Look at pictures. Borrow a friend’s amp, or go to an audio meet. In the end, pick an amp that meets your needs and expectations.

122 thoughts on “On the ODAC, and Recent Reviews”

    1. Maty,

      No, RCA’s will come later (ODA+ODAC). Check NwAvGuy’s blog. There’s a link at the very beginning of this article.

      1. If it have headphones and speakers output, I will buy one and write an annotation -as is my custom- if it not shoot the final price with shipping costs to Spain, if Spanish banks continue to operate (very bad to my country today) 🙁

        1. Hi.

          Just want to let you know that the O2 is not meant for speakers, but to operate headphones. However, you can modify RCA input and output yourself if you really need it.

  1. if only the people would actually use their brain and be logical and rational while making their statement and comments. neither both nwavguy or mike would have said anything against each other but for the few vitriol being aimed at them. i mean, come on, we have our preference but do we have to throw mud to those that oppose our view? and this coming from both the pro-objective and the anti-objective group.

    i love nwavguy’s blog. it’s a revelation, especially to those who wanted to do such measuring but can’t afford them. he spoke with such logic and rationality, it’s hard to argue against his facts. however, we are human, and human do err. a lot. we are not perfect. thus, our defect make us different from each other. which, in turn, give us our own preferences. which is what headfonia championing. in the end, it’s up to us to decide, which suit us the most. heck, then again, both yours and nwavguy’s amps are one of the cheapest in the market with some of the best review available. might just get both the c421 and the o2+odac then. 🙂

    1. Hi there JDS Labs,

      The provisional O2+ODAC Combo looks just great! Any ideas on how much the O2+ODAC Combo will cost?
      I will most certainly get one… or two 😉 Can’t wait.


      Iter Erranti – [email protected]

        1. Is that with or without the adapter? If it isn’t, is the adapter an additional $12 like with the standalone O2?

          1. Batteries are gone, so that’s with the AC adapter (North America price only).

            Edit: To keep things simpler, the O2+ODAC combo does not include a power adapter by default. The Triad 12VAC adapter can be found under the ‘Accessories’ category.

  2. Hey!

    Incredible price! Thanks for the info.
    I have another question regarding costs and prices. Will there be more expensive units released, with perhaps more expensive or special finishes?

    Thanks again,


  3. I was thinking of a more durable and perhaps aesthetically more polished enclosure, and perhaps in various color options. Something very minimalistic, nothing difficult or with excessive detail, just the essential, but sturdy and if possible in a couple of color variations. I could perhaps come up with a design, but I don’t know what kind of costs materials could impose, nor which are the most appropriated materials. Maybe it’s just a silly suggestion of mine, but I wouldn’t mind paying a little extra to obtain a more sturdy build quality and some enclosure options.

    1. I certainly wouldn’t protest a minimalist, anodized aluminum aesthetic. It would be seamless among my other gadgets.

    2. 50$ for tiny ODAC enclosure 😀 I can buy such enclosure for 5$. Drill 2 holes and you have the same quality enclosure 10 times cheaper.

      ES9023 DAC chip costs only 4$ (if you ordering 10 pcs (even cheaper for big orders)), Tenor TE7022 0.15$, pcb ~3$, other components cost 0.0x cents. I think overall ODAC value max. 15-20$.
      You guys making good business here 😀

      1. @Mantas: Maybe that’s possible where you are, but I can assure you that your estimates are way off here. As explained in NwAvGuy’s blog, ODAC is sourced and assembled in the United States. Chip manufacturers do not give North American companies the same prices given to Eastern companies. US assembly and custom machining labor is much higher also.

        At NwAvGuy & YoYoDyne’s request, we’re actually selling the ODAC boards to consumers barely above wholesale cost (minimal profit). If the ODAC really did cost only $15-$20 to build, our price would not be $99! The lower a price, the more we’d sell. It’s basic economics.

        We are free to add reasonable markup to our cased products. If you have the resources and time to assemble the ODAC, by all means, go for it! We’re huge proponents of the OSHW movement and DIY projects. JDS Labs wouldn’t exist without the OSHW infrastructure that’s evolved from DIY startups like Sparkfun, Adafruit, etc. But the fact is, custom materials and labor costs in the USA are quite high. We don’t import. We set prices that work for our customers and the business, and we build within the USA. If a price doesn’t work for us or for our customers, then it’s not a viable product and will not be sold.

        With the above in mind, I completely agree that the low price of the bare ODAC ($99) makes the standalone edition seem like price gouging. In actuality, the ODAC itself is barely a profitable piece.

        You’ll find that we have the lowest assembled O2 and ODAC prices in the world. We’ll add a “25% off” note to emphasize the low $99 ODAC price.

        Thanks for your feedback!


  4. Would be great if the USB port is on the back. Even better if the USB port and the 3.5 output line up with the c421’s USB port and 3.5 input! We all love a symmetrically pleasing stack of gears don’t we.

    Add a rubber band with “ODAc421” printed, then a right-angled 3.5 IC (like the ones ALO offer for their CLAS+Rx combo at a more sane price), and voila!

    1. We’re not in charge of circuit board design for this project, so nothing can be done about USB or audio jack placement…

      1. You could turn the PCB around, and use panel mounted Jack on the front. It would probably require a larger case though. Alternatively, I would be fine just using my dac facing backwards with both ports on the back. Maybe you could make a rear plate with a nice logo and name on it?

          1. Panel mounted jacks and a larger case won’t be feasible, sorry. We’re locked to the ODAC’s layout.

      2. I really wish there was something that could be done about the USB port placement on this dac. I absolutely love the c421, but this is just frustrating news as obviously this and the c421 would make a nice pairing.

        Sit the c421 next to this and the cable management problem becomes obvious. Matching cases, but an ergonomic puzzle.

        In the future, I’d love to see a bit better case on the c421 (not that the current one is that bad) as it needs a bit of consumer grade polish…ala Sony products. But ergonomics really need to be addressed as well. For instance, when using the c421, I can’t tell when it is finished charging nor when it is low on charge as those lights are on the rear of the unit. I’d also like to see the power switch on the front of the unit, and placing the gain switch on the rear would be fine as it’s usually a set and forget item. Also, placing the source jack on the rear of the unit would make more sense, cable management wise, as most outboard dac’s jack are also on the rear…makes for a much cleaner cable setup.

        Don’t get me wrong though. The c421 is a nice 1st generation product, but I can’t help to see where it could be with more forethought on the next generation. So a minor placement change in the USB port would go a long way to integrating it with existing JDS products.

    1. @Hyk: Please see top of article: “ODAC absolutely requires a headphone amplifier for proper operation”

      Yes, the standalone ODAC needs an amp.

  5. Will ODA+ODAC and have volume control knob (for preamplified loudspeakers) and is there any estimated price for that combo?

    1. ODA isn’t ready for release. We have no more information than what’s available at NwAvGuy’s blog. Pricing can’t be determined until he finishes the design.

  6. Since the ODA will have a bigger enclosure than the O2, maybe it’s possible to put the bass boost circuit inside? I wouldn’t mind JDSLabs-customized ODABB =)

  7. how about the rear panel on the ODAC? I think it would be neat to have the name on the rear panel, so you could turn it around and face the inputs towards the rear.

    1. NwAvGuy and YoyoDyne consulting decided to omit the line-out jack, so adding 3.5mm to every board would raise cost of every O2+ODAC combo.

      If you need the line-output jack, a standalone ODAC will be a better solution.

  8. Any chance to offer a back plate with the USB and 3.5mm jack punch out ? I can add the jack, but don’t have the machining capabilities.

    1. That’s what the standalone ODAC is for.

      NWAvGuy did not intend for the line out jack to be used when combined with the O2, as the load would be split into two amps this way (the O2 and the external amp). This isn’t a best practice. Thus, we will not produce the O2+ODAC rear panel with the line out jack.

      1. I see. It was just so having one unit can serve as a source for my speakers as well as a headphone amplifier/source so when I want to use speakers, I turn off the headphone amplifier. I will not be double loading the output of the ODAC though. Only speakers OR headphones, no point in both at the same time.

        BUT, thanks though.

  9. Very enthusiastic for the ODAC+O2 combo to be up for sale
    going to pre order ASAP!

    regarding the possible enclosure upgrade:

    seems like an interesting option for people who are looking for a more aesthetic look and/or durable enclosure, for a few more bucks I’m sure JDS Labs can lure in a crowd.

  10. Hey, one quick question.
    I will preorder an ODAC as assembled board only. Could I also get the optional 3.5mm line-output jack from you? I’m happy pay for it and to solder it myself.
    Thanks, Jonas.

      1. good idea.. It would be really, really cool for you guys to offer some rear panels with a line out hole too.. If possible

  11. I’m a total novice about DIYs and audio hardware in general. However, I’ve somewhat been keeping up with the O2 ever since getting into this hobby. The only thing that has stopped me from buying it months ago is that I happen to come across it just when its creator announced the ODA and ODAC. So I’ve been patiently holding out on buying my first amp and DAC.

    Anyway, this may be a dumb question, as I haven’t even heard what any of these amps sound like, but the bass-head in me is wondering if there’s a way to implement a bass boost feature to your O2 models, like how you’ve done to the cmoy?

    1. NwAvGuy’s no-derivatives licensee means no chance of adding bass boost to the O2. It’s not exactly in the scope of an objective amp 😉

      Our c421 has bass boost.

        1. O2 technically gives superior benchmark performance. But I personally prefer c421. It’s actually portable and has bass boost, which are important features to me.

  12. If I purchase the O2+ODAC combo, and if I purchase another amp down the road (say, c421 ;)) can I still use the ODAC by itself?

    1. No, the ODAC is hardwired to the O2 in the O2+ODAC combo. Choose the Standalone ODAC instead. You’ll be able to use this edition with any amp.

      1. I’m curious about ‘any amp.’ Can the standalone ODAC be used with a standard integrated amp for passive loudspeakers as well or is it only for headphone amps?

        1. This is important for me too. (I have preordered one.) I hope ODAC can feed into an integrate amp or a pre-amp.

          1. I purchased the Jawbone BIG JAMBOX today and hooked up the combo unit.Wow was I one happy camper.I needed the portability and size for traveling and using a converter for the ac power supply and my Ipad in my truck.The combo provides a super strong signal with the volume on the ODAC combo barely on.With base boost and the combo volume at 11 oclock the Jambox is unbelievably loud and crisp.I can only imaging what a larger active speaker will sound like.I did a lot of research and reviews and I have narrowed a budget bookshelf speaker for my 2.0 home speakers for pc and TV to the Behringer Digital Monitor MS40 $129.00- $163.00 depending where you buy from.The high end pair would be Audioengine 5+ (A5+) Premium Powered Speakers $500.00.I have spent 2 weeks studying reviews and reliability complaints ect.Of coarse as if you are buying the ODAC combo or any other piece from JDS or the other retailers we have all read the blogs on your ear has the final say.I am confident my research will be a no brainer and I will do a follow up on the cheap and expensive pair of speakers.I can only give a listening review,I am not an audiophile numbers guy.I highly recommend the Jawbone BIG JAMBOX.I listened to the sansa play 5,B&W ,Bose and other similar products I returned them all and kept the Jambox.My ear prefers that speaker and it is plenty loud.

    1. The 3.5mm jacks on the O2 are 5-pin parts (two sets of input/output terminals). Only one set of terminals is active at a time. The primary set is active when a plug in inserted; the secondary set is active when no plug is inserted.

      The ODAC in the O2+ODAC combo is hardwired to the secondary set. So, the O2 acts as normal when an input source is connected, and the ODAC is bypassed. When an analog source is disconnected, the ODAC becomes the active input source.

  13. I’d would love to get the ODAC and O2… been wanting to for months. Only hitch is that I think I prefer the convenience of having a wireless digital audio transmitter and receiver like the audioengine D2 (http://kenrockwell.com/audio/audioengine/d2.htm). Perhaps the O2 might work just as well with the D2’s RCA output using an interconnect adapter?

    1. One can’t possibly judge two audio sources without benchmarking both from the same measurement equipment. It’s unlikely to be outperformed by the ODAC (measurements shown are less impressive). But if it meets your needs, why not?

      1. It seems that the ODAC can be inserted into the O2 case and still retain the batteries. If the ODAC is mounted to the underside of the O2 board with a little filing to the sides of the ODAC board it will fit. What type of wire is recommended to connect ODAC line out to the O2?

        FYI a video or pics of how to properly connect these would be nice.

        Thanks again to JDS Labs and NWAV Guy.

    1. We shipped as many assembled ODACs as possible today:

      Only enough endplates arrived this afternoon to ship 10% of preorders. We should be up to 50% by tomorrow, and 100% sometime next week. The wait is a few days longer than our estimate, but our machine shop took their time in perfecting these parts (at my frequent and possibly obsessive requests). Every single edge and jack cutout is beautifully chamferred. I’m extremely pleased with how they everything turned out, both visually and acoustically. It’s worth the wait!

      1. Thanks John. You must be super busy these days with new orders. I only ordered last night, so you won’t have mine shipped until next week. but i would rather wait for a perfect build from you. 🙂 Thanks!

      2. John, any update on the stand-alone ODAC? Have you received enough end plates to cover all recent orders? I am still waiting for mine :-). Thanks.

        1. I flew to the machine shop over the weekend and met with them on Monday morning. The vast majority of Standalone ODAC endplates had been machined, but still required plating and artwork. This is normally a 2-4 day process. Well, it took them 4 days this time. Finished endplates should be shipped to us this afternoon by UPS Next Day (arrival Monday).

          Once parts are in, we ship fast–about 75 packages an hour.

  14. Is the standalone version in the full sized c421 enclosure (so it matches the measurements under the c421 specs)? Or has it been shortened to just the length needed for the ODAC? I would assume the former, because it would be less cost, but when looking at the renderings it gives the impression that it is in fact shorter. It would be nice if it was smaller of course, I would pay a bit more for that, but if not, I will still be happy with it.

  15. Being a early 70’s rock teen I have listened to reel to reel re-verbs tube amps ect.I purchased the 285.00 combined unit and I am blow away.The separation and sound quality is just like the old Marantz days.Blown away by this product to say the least.Anyone skeptical about purchasing should just go ahead and get one.You will not regret it.This product has and will make it’s mark.This is audiophile quality.Thanks Bob S

  16. in the future, can i just buy the assembled pcb only? without the case?

    or i must buy the standalone odac?

  17. Hi, I’m a really a newbie in this DIY world buat I want to have ODAC with 2x RCA jacks.

    From the instruction:

    If using RCA jacks:
    1. Solder short wires between RCA jacks and the line‐output header of the ODAC circuit board. Pinout of the line‐output header is: Left, Right, Gnd, Gnd. Do not alter jumpers J1, J2.

    Perhaps a few pictures will help a newbie like me to understand the instructions above?


    1. Pictures will be added to the instructions soon. You can look at the O2+ODAC pictures for now, on the previous page.

      The center pin of an RCA jack carries the signal (Left or Right), and the outer jacket is ground. This should be all you need to know to connect wires between the RCA jacks and the ODAC board.

  18. Hi John
    Just received my ODAC in its stand alone case today. To say I am pleased would be a considerable understatement. I am currently using it with my O2 amp but at your suggestion I bought it in its own stand alone case so I can use it with other amps as well. As usual your suggestions are bang on and provides me with great versatility.

    I now have several of your products in daily use in my household including 2 JDSlabs cMoybb
    c421 portable amp
    JDSlabs O2
    JDSlabs stand alone ODAC

    Your excellent products and your wonderfull customer service have made dealing with you a great pleasure. I look forward to new products from you in the future as you have made me a lifelong customer for sure.

    John H

  19. Hi John – I have ordered an ODAC for my setup, but I am curious as to whether it is what I need. I have a PC as the source, an amplifier feeding two speakers, and an active subwoofer. I will connect the ODAC to the PC via USB and to the amplifier via 3.5-to-RCA, and I can use the high level inputs/outputs on the subwoofer to feed it. Is this correct?

    As it sits currently, with the PC feeding the amp directly via 3.5-to-RCA, and then the subwoofer thru the high level in/out, the sub plays a distorted signal that is wrong. I think it is playing the left/right signal thru the sub, likely due to the fact that I am using the green 3.5m out from the mobo labeled as “left/right”. Any help is appreciated.

    1. Danny,

      Yes, an ODAC should work fine as long as your speaker/sub amps accept line level input (they must if they use RCA input).

      You need to adjust the crossover frequency and gain on your sub amp. When crossover is set too high, mid-range and higher frequencies pass through the sub. 80Hz is a good ballpark figure for crossover.

      Set gain as low as possible, play a deep test tone at maximum volume at the PC, and then increase gain until you hear distortion. Back off a little.

      And that’s how you tune a sub amp by ear…

  20. Any update on the stand alone ODAC orders? Can you please tell us what order date you are up to? After hearing the positive reviews coming out I’m looking forward to hearing it paired up with the O2 I got from you a while back. Thanks.

    1. Mark,

      100% of Standalone ODACs will ship by Tuesday.

      Check back tomorrow for a bigger update.


  21. How about boards plus backplates? should I just upgrade to the standalone vs trying to add this to my O2?

  22. was trying to ask when they are shipping. have had my preorder for a while. just wondering if I should upgrade to full enclosure so that mine will get shipped sooner. can’t wait 🙂

    1. Most orders have shipped by now (> 90%). We’re expecting a final shipment of rearplates to arrive this week, which will allow us to complete all outstanding orders.

      We added a laser engraver and CNC to our shop last week. No more production delays in the future! Pictures and videos to follow 🙂

  23. Do you send shipping notifications as course of business? I preordered on May 14th. guess I am one of the lucky 10%. 🙁

  24. Received my ODAC right on schedule yesterday. Plugged it in, sounded horrible. Then I realized the plug was only half way in…… Much better now. Thanks for getting them out the door as soon as was possible with your supplier timetables. I’m a satisifed customer – for the second time.

  25. Hi. I have a c421 opa 2227. Would the ODAC improve the sound quality once it’s paired up with the c421?

    1. Depends what source you’re listening from now 😉 ODAC will be a significant improvement over a low quality computer sound card. If it’s a reasonably high-end sound card, the difference may be less apparent. But measurably, yes, ODAC generates excellent output.

      1. I’m using it with the on board sound card. So if I use the ODAC with c421 it’s gonna sound much better right? And is the ODAC on par with O2 amp?

        1. Yes, ODAC will outperform an onboard sound card. It produces true line level output and measurably excellent signal quality. Very few onboard solutions come even close.

          ODAC is a “different animal” than O2, so I can’t answer your second question. One is a DAC, the other is an amp. They’re both designed by NwAvGuy for maximum performance in their respective spot in the audio chain.

  26. Sorry if this question was already asked or so, but there’s this question I’ve been wondering for a pretty long time. If I purchase the O2 + ODAC combo for use with a computer, would I still need a mini to mini line to connect the O2 with the ODAC then a usb line to connect to the computer or is the mini to mini process skipped?

    If true, then

    If I want to use the O2 + ODAC combo for the computer all I need is the AC adapter, the product itself, a headphone, and the usb line am I correct?

    Sorry for the question, I am really new to these stuff and your feedback would be very much appreciated! Thank you.

    1. There’s no need for a 3.5mm mini-to-mini cable if using the O2+ODAC with your computer. The audio signal is supplied digitally through the USB cable.

      We provide a 3ft USB cord. All you need is the O2+ODAC, headphones, and an AC adapter (see “Related Items” on the store page).

      On a related note: Only one ODAC is in stock!

  27. From many reviews I read, ODAC can be a really great addition to my setup.

    However, I notice there is no 3.5mm line in for Apple LOD. Is there any way I can listen from direct iPod>standalone ODAC>amp setup? Thanks.

    1. @jfw: I may be wrong, but iPad is the only device which can actually stream digital audio output (no support in iPod or iPhone). There’s a similar dock adapter for iPad called Camera Connection Kit. But it’s not useful with iPod or iPhone.

      You can use the ODAC with Android phones, with an appropriate USB cable. In summary, ODAC is supported by:

      -Windows, Mac, and Linux computers
      -Android phones

        1. Not sure. We don’t have any Anroid devices here. May have to order a few.

          ODAC needs a digital audio stream. So if a device can output digital audio, ODAC can make use of it. For iPods and iPhones, this is merely a software limitation.

          1. Hmm seems like ODAC is not the solution for my current rig. Might as well just get ODAC+O2 for my desktop setup as soon as I saved up enough money 🙂

            Thanks for the replies!

        1. jack: All RCA Output, Standalone ODACs are built with RCA jacks on the back side and a 3.5mm (and USB) jack on the front. You can only use one output at a time.

  28. I’m hooking up my ODAC for the first time to my desktop at work and what a surprised!!! i hear crackling noise along with the music. I tried out multiple cables and plug in locations 🙁 what a dissappointment…

    EDIT Aug 7, 2012: The issue is taken care of with a usb hub…. thru my HP monitor… 🙂 I’m pretty happy…. one simple solution. I’m a signal integrity engineer and this is still a puzzle why whatever noise is riding on top of that differential signal could still get thru the DAC…

  29. Could I use an ODAC without amplifier for a Sennheiser HD 595 headphone with 50 ohms? I have recently tested DAC/Amp combinations and wasn’t really impressed or satisfied with any of them and I think an old internal soundcard without headphone amp of a PC I don’t use anymore is better than any of them, or at least no worse. If an ODAC provides full hifi-soundquality I think the result might easily beat the combi-devices I used, which seemed to be severely restricted in several ways anyway.

    1. @FmH: ODAC has no amplification output stage, so performance would be severely impacted without an amp. Yes, ODAC requires a headphone amplifier. Even your soundcard has an integrated output stage (even if it’s not formally declared a “headphone amp”).

  30. Hi there!

    I’m interested in buying a standalone ODAC for a media PC. I’d like to build my own enclosure, perhaps packaging it in something novel.

    My question is regarding shielding and grounding. Both my PC and amp are in metal cases, grounded to the mains. If I build the ODAC into a metal enclosure, should the input and/or output be grounded to the enclosure, or should One or both be isolated?

    Currently I just have a 3.5mm to RCA cable between the PC onboard audio and the amp, with no ground loop noise issues, squealing from USB etc.



    1. Simon: ODAC users have not reported ground loop noise.

      We discussed proper grounding with NwAvGuy before he disappeared. He had no officially measured recommendation at the time, but was inclined to suggest direct grounding of the ODAC’s USB connector to its enclosure. This hasn’t been necessary in practice.

  31. Will be placing my order soon.
    You got me at ….” and voila:” 🙂

    How many sites I have visited and quickly left that expound their (not so) original ideas by finishing with…’ and wallah !’

    You guys rock…. Audiophiles AND literate.. if you take that much care with words then I just know your product will be all you promise and more.

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