tag:blogger.com,1999:blog-6890046273025265768.post4696050421356103011..comments2024-03-18T03:10:30.572-07:00Comments on NwAvGuy: O2 DetailsNwAvGuyhttp://www.blogger.com/profile/00309644608738074125noreply@blogger.comBlogger199125tag:blogger.com,1999:blog-6890046273025265768.post-497705231497916282012-05-01T11:21:26.016-07:002012-05-01T11:21:26.016-07:00Due to an issue with Google Blogger with more than...Due to an issue with Google Blogger with more than 200 comments, I have disabled comments for this article. Please see the <a href="http://nwavguy.blogspot.com/2011/08/o2-summary.html" rel="nofollow">O2 Summary</a> for the latest comments and you can leave any comments there.<br /><br />POWER JACK PROBLEM: Please see the <a href="http://nwavguy.blogspot.com/2011/08/o2-summary.html" rel="nofollow"NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-70728921533346796972012-03-12T02:56:05.728-07:002012-03-12T02:56:05.728-07:00Yay just finished my O2 and it sounds great! I wa...Yay just finished my O2 and it sounds great! I was able to more or less build it and pass all testing in one go which is testament to how easy this thing is to build. <br /><br />The only issue I had was I was hearing some odd humming when pushing down on the volume knob which had me scratching my head for a bit....then I noticed that since I was using a 20mm pot the metal faceplate of it was Yangoranghttp://yzrandome.blogspot.com/noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-53952054981295479472012-03-07T21:55:59.535-08:002012-03-07T21:55:59.535-08:00Yea....their website pictures look wayyy nicer tha...Yea....their website pictures look wayyy nicer than what I actually received which is such BS.<br />My quotes for this front panel will likely be quite astronomical since I'm quoting for such a small quantity and CNC milling/engraving typically has an expensive initial setup. Perhaps if more people want this thing I could order like 20 and distribute them via my eBay store.Yang Zhouhttp://yzrandome.blogspot.comnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-19250087790303114642012-03-07T11:28:45.152-08:002012-03-07T11:28:45.152-08:00Hi Yang. I also got a front panel from JDSL and I...Hi Yang. I also got a front panel from JDSL and I agree with you. I actually scraped off the 'DISTRIB BY JDS Labs' part because Im not a fan of it on my panel. I'd be interested to see what they send you back.Rob Mellohttps://www.blogger.com/profile/10783724563309151341noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-77490223993104863582012-03-06T19:12:08.367-08:002012-03-06T19:12:08.367-08:00Does anyone else think the JDSLabs O2 front panels...Does anyone else think the JDSLabs O2 front panels are not so great? The lettering feels rather cheap on them, and the edges and finish feel rather rough.<br />I'm requesting a quote from a machine shop for some stainless steel front panels right now - here's a rendering of the CAD model I submitted: http://i429.photobucket.com/albums/qq20/Yangorang/Image-1.jpgYang Zhouhttp://yzrandome.blogspot.com/noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-50221050120174828622012-03-05T18:02:31.672-08:002012-03-05T18:02:31.672-08:00You need to be careful because +/- 12 volts (24 vo...You need to be careful because +/- 12 volts (24 volts total) from the O2's AC supply puts more stress on an op amp driving headphones. The O2 works because it uses two op amps in the output stage which provides twice the power dissipation. But a typical single op amp Cmoy might have problems going from 9 volt rails to 12 volt rails.<br /><br />In terms of the JLH vs O2 I don't see any NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-68675857841156588282012-03-05T11:11:40.785-08:002012-03-05T11:11:40.785-08:00Sorry if these questions seem like noobish or I ha...Sorry if these questions seem like noobish or I have missed some essential facts, but the whole documentation of O2 is quite a task to grasp.<br /><br />I don't have much of experience of DIY electronics except some soldering of DIY speaker crossover circuits and low pass filters etc. so I am aware only of the basics of electronic designs. I do also have engineer's degree but on a quite Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-15204721659168908182012-02-25T14:03:34.488-08:002012-02-25T14:03:34.488-08:00NwAvGuy,
I just want to give a big thank you for a...NwAvGuy,<br />I just want to give a big thank you for all of your hard work on the O2. Your countless hours to create such a fine sounding amp, and the time to help shepherd many of us newbies through the build and test process is unfathomable. As a first time DIYer, I built my 02 with absolutely no issues by simply following your vast and detailed instructions. My Q701's now absolutely Rob Mellohttps://www.blogger.com/profile/10783724563309151341noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-48513486264830681232012-02-23T07:09:31.540-08:002012-02-23T07:09:31.540-08:00There used to be a few eBay LME49600 bare boards f...There used to be a few eBay LME49600 bare boards for sale but I have been told by others they have various problems (no surprise for audio stuff being sold on eBay). The LME49600 is fussy about PC board layout and some designs have issues with excessive DC offset.<br /><br />Unless you have really rare headphones that need more than 7 Vrms, or more than 200 mA peak current, the LME49600 has no NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-2989316859676384682012-02-22T22:41:14.844-08:002012-02-22T22:41:14.844-08:00Do you know of another LME49600 based amplifier de...Do you know of another LME49600 based amplifier design that's a bit more practical? I was honestly just considering buying the LME49600 reference board to try out but the thing costs $250 so I'd rather just build an O2 heh...Yang Zhouhttp://www.linkedin.com/in/yzhouynoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-11436194148715430792012-02-20T20:23:28.537-08:002012-02-20T20:23:28.537-08:00With the AC power disconnected, you could carefull...With the AC power disconnected, you could carefully heat the solder connection and use a small flat screwdriver to "lift" one end of D1. Then plug the AC in and and make the appropriate measurements to verify both MOSFETs are off. Then unplug the AC, solder D1 back in place, and do the same with D5.<br /><br />You can also use cheap disposable headphones and check for bad transients on NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-74483333641669185002012-02-20T18:28:08.336-08:002012-02-20T18:28:08.336-08:00How would you test if the MOSFETs were damaged if ...How would you test if the MOSFETs were damaged if you were building an O2 for AC only operation (i.e. battery terminals were not installed, and batteries were not purcahsed).Kennoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-37364622079283597562012-02-18T17:17:58.751-08:002012-02-18T17:17:58.751-08:00I would guess if you listened blind, level matched...I would guess if you listened blind, level matched (exact same volume) driving the same headphones from the same source, they would sound the same. But our brains can easily deceive us otherwise. If one has the volume set slightly higher, for example, you will hear a difference.<br /><br />But it is possible something is wrong with one of your O2s (assembly error, soldering problem, etc.).NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-1016815015789769622012-02-18T07:37:23.671-08:002012-02-18T07:37:23.671-08:00Hi nwavguy!
I've built TWO O2 amps now with th...Hi nwavguy!<br />I've built TWO O2 amps now with the same parts, but they sound a little different from one another. I'm not sure which is better, but would part variation account for the differences?<br />Another difference I could tell is my soldering standard for the second one is a lot better than the first, because I don't have a lot of practice. Might that account for the Chia Weihttps://www.blogger.com/profile/00897735836697322919noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-45995126212760852852012-02-16T14:29:22.610-08:002012-02-16T14:29:22.610-08:00Here's a fun fact : My O2's power manageme...Here's a fun fact : My O2's power management section wasnt working.So I thought that mosfets were fried.A few hours of investigation , measuring etc I found out mosfets were not the problem.But the comparator's voltage referance was.<br />Genius me bought the most efficient Led I could find.Real bright with just 1mA.But the forward voltage is 1.3V!<br />Sorry for extra comment in thispeahttps://www.blogger.com/profile/10899895922399055584noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-46866031010272433392012-02-03T19:40:17.241-08:002012-02-03T19:40:17.241-08:00There have been several parts questions lately. In...There have been several parts questions lately. In the interest of keeping the comment count down (Blogger has problems with more than 200 comments per article), here are all the answers in one message:<br /><br />NJM2903D can be substituted with any LM2903 in a DIP8 package. Mouser has several like the LM2903NG and LM2903PE4.<br /><br />As I've answered a few times already, the mil spec NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-37526264600723503222012-02-02T06:45:34.957-08:002012-02-02T06:45:34.957-08:00The line out from the Benchmark was driving the O2...The line out from the Benchmark was driving the O2. I also tried using my Transporter (which has an extremely high quality DAC and analog output stage) to drive both the DAC1's analog line input and the O2. My ABX box can switch both the input and output simultaneously so the Transporter was only driving one device at a time, not both at once.NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-85502353565600427622012-01-30T02:27:12.621-08:002012-01-30T02:27:12.621-08:00NwAvGuy> Maybe it's already been discussed ...NwAvGuy> Maybe it's already been discussed here, but I'm just curious - when comparing O2 vs. Benchmark DAC1 in blind listening tests when nobody could tell the difference, what gear was used to drive the O2 (ie. the input)? Some high-quality reference sound card or the DAC1 itself via its analog outs? Could you please explain more about the test? Thank you...Mireknoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-79475729420535664862012-01-27T06:45:57.285-08:002012-01-27T06:45:57.285-08:00@bellsprout, I talk about the gain resistors in th...@bellsprout, I talk about the gain resistors in this article. Also see my All About Gain article from last fall. There are many dynamic headphones that need more than 2 Vrms including even my HD650 and the HD600 as well as many AKG's and Beyers. The DT880-600 needs over 5 Vrms. Also see my More Power article.NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-50273876029554917282012-01-27T01:07:30.813-08:002012-01-27T01:07:30.813-08:00Looks awesome, NwAvGuy! Would you recommend a marc...Looks awesome, NwAvGuy! Would you recommend a march larger gain resistor for closer to unity gain if driven from a 2V source like most optical DACs? I don't think there are any dynamic headphones that need more than 2V. Lower gain improves performance as you say right?bellsproutnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-41136875763442989702012-01-26T18:53:45.881-08:002012-01-26T18:53:45.881-08:00Looking forward to receiving and testing out your ...Looking forward to receiving and testing out your O2 Reference amp nwAvGuy. I hope and am sure it will live up to my expectations. Scooter turned me onto this amp and I hope it pairs well with my DX100. Thanks :)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-4390567973954835462012-01-25T06:44:08.410-08:002012-01-25T06:44:08.410-08:00@Anon, You can only get rid of D2, D6, R1, R2 and ...@Anon, You can only get rid of D2, D6, R1, R2 and the battery terminals. The 9 volt regulators would be better if you don't need more than 5 Vrms maximum output. Unless you have something like Beyer DT880-600 headphones, 5 Vrms will probably be more than enough. If you're not sure about your current or future headphone requirements, see my <a href="http://nwavguy.blogspot.com/2011/09/NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-18007558638426197812012-01-25T02:22:44.343-08:002012-01-25T02:22:44.343-08:00Newbie question..
If I want to build the O2, stri...Newbie question..<br /><br />If I want to build the O2, strictly for AC power, which parts should I omit? Also, would the MC7809 and MC7909 be considered 'better' for this purpose?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-31967238481664638362012-01-24T05:46:22.551-08:002012-01-24T05:46:22.551-08:00The 2068 is in no way a substitute for the 4556. T...The 2068 is in no way a substitute for the 4556. They're totally different op amps designed for different applications. Mouser currently has over 400 of the NJM4556ADD in stock. That part number is listed as an alternate in the Bill of Materials spreadsheet. The extra "D" just means it has even lower noise than the standard version of the 4556.<br /><br />The optional 10-0518-10 NwAvGuyhttps://www.blogger.com/profile/00309644608738074125noreply@blogger.comtag:blogger.com,1999:blog-6890046273025265768.post-70661618557379919822012-01-24T02:19:34.875-08:002012-01-24T02:19:34.875-08:00Ah, OK I see it now =)
Just to make things easier...Ah, OK I see it now =)<br /><br />Just to make things easier, this is the basic components cart at Mouser https://mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=7c12d3aeb3<br /><br />The NJM4556ADD is replacing the AD, changed one 3.5mm connector to Green (the other is blue), and added 2x 1.5K Ohm resistors (594-SFR16S0001501FR5), replaced one knob (Blk/Wt) to Blk/Red<br />Changes are at Abderrahman Najjarhttps://www.blogger.com/profile/11929136460617625005noreply@blogger.com