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  #481  
Old 02-29-2012, 12:56 AM
Jegendal Jegendal is offline
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Hi guys. Lurker here that just ordered an o2 from jdslabs and am very much looking forward to it arriving

I was also wondering if someone could double check that the following AC adapter works? From what I gather it should but I thought I'd check just to be sure. http://translate.google.com/translat...ledInformation
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  #482  
Old 03-01-2012, 06:28 AM
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El C El C is offline
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According to JDS Labs any AC-AC adaptor should be fine, as long as it outputs around 14-20V AC and a minimum current of 200mA.

Link: http://www.jdslabs.com/pdf/Instructions_O2.pdf
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  #483  
Old 04-02-2012, 06:03 AM
lorriman lorriman is offline
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To encourage self-builds for those new to soldering and electronics: I just completed a newbie build successfully. I have no prior experience of soldering and nearly zero knowledge of electronics. I justified the build by the knowledge that I could use a half-decent soldering station, as recommended by Nwavguy, and digital multimeter to fix things (which in fact I already have, covering the cost of the soldering station even before I built the O2), and that I would make a modest saving on the pre-built o2's while also tapping in to a source of satisfaction (which I believe is more important that pleasure or even pain) by the fact of having built it myself. Of course nothing beats both designing and building: Nwavguy must be a walking incarnation of satisfaction which he can savour again and again; second only to bringing up a well-adjusted and happy offspring. I'm a total sucker for objectivity (for example, I have immense disdain for statistics which I have studied; half the eff-ups in the science world are due to stats, and when politicians talk of evidence-based policies the are really just trying to satisfy their own ideology with a veneer of objectivity) so one way or another I was going to have to get my hands on an O2.

I did have a hiccup: I didn't understand Nwavguy's instructions on getting the electrolytic capacitors the right way around (it was 3am) and ended up installing them the wrong way around. The build failed the very first test much to my misery, with the capacitors bulging out and heating up. I almost grumbled at God. Once I worked out the problem I replaced them (I have two more kits of parts for two more builds), since they were probably dead, and after that it passed all the tests and is driving my current-hungry T50rp planar magnetics for which previously I had to use a full sized amp. Taking the capacitors out was jolly hard even with a lot of solder-sucking copper 'braid'. I was afraid of damage to the pcb though I did have 4 pcbs in case of mishap as copper trace damage is apparently a commonish problem and I am a newbie after all.

I do have one or two words of advice to other newbies.

Use the diyaudio thread for help.

Use assembled board photos in case of doubt.

I used 63/37 solder instead of the traditional 60/40; it decreases the chance of an accidental solder-bridge.

I took Nwavguy's advice and got a 'helping hands', but in the end I did most of the soldering without it and could have done it all, really. If you are cash-strapped that's one you can probably forgo although they are cheap.

I examined my soldering with a loupe. The loupe helped me determine a short circuit that I couldn't otherwise see and also helped me determine if one of the components was touching another as warned against by NwAvGuy (it was). You can't get decent loupes of ebay, especially not for $3: they are bogus and have poor image quality and are not as powerful as advertised. For the UK get a 10x 15 loupe from quicktest.co.uk. Don't be tempted by the more expensive 15x or higher loupes. I was and regret it: it's too powerful and the depth of field (visible plane of focus) is too thin and really very awkward. Quicktest does warn of this quite storngly so I have only myself to blame. I'm living with it. You also need a 10x loupe for jewellery purposes which means mine is not as general purpose. [sigh]. However, ultimately the loupe is still jolly useful. I use it a lot for all sorts of random things. It's quite a power to be able to see tiny objects/details so easily. A worthwhile investment. I would recommend the larger diameter loupes (I've used both)

I made the mistake of fiddling with the calibration screw on the soldering station. I'm now fairly sure that the station is underheating and yet I have no way of correcting my 'adjustment'. Emailing the distributors resulted in a "there is no way to calibrate". Darn. Even a cheap, chinese coupled(?) thermometer doesn't get me repeatable measurements.

I used both an anti-static wriststrap and mat to protect the ESD sensitive mosfets. Don't switch on the o2 on the mat: it is a (probably weak) conductor and might cause an issue.

I was tempted, by impatience, to plug in the opamp chips and see what happened with a pair of sacrificial headphones before doing all the tests. I didn't succumb. Considering the wrongly soldered capacitors I'm very glad that I didn't. Follow the test advice: don't plug in the opamps until the right time.

I reckon it's probably worth getting more than one component kit for a newbie. I needed the spares (also for a resistor). And don;t be put off if you are red-green colour blind: I am and the DMM with an ohms meter did the job.

I'll add more if I think of it.

In the meantime: many thanks to Nwavguy. Not only has this been a lot of fun but I have been moved to learn hobby electronics. And the blog is just mind-blowing as well as being highly readable. However I did find the headphone power/voltage calculation page impossible to understand even though I like my maths. That may just be my lack of electronics knowledge, of course.
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  #484  
Old 04-11-2012, 10:18 AM
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NwAvGuy NwAvGuy is offline
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Just a note to say thanks for all the kind words here, like those from lorriman above, and sorry I've not had time to keep up with this thread. If anything comes up here that's going unanswered and I might be able to help with, please feel free to let me know so I can pop in and perhaps post an answer. I can be reached through my blog and I should get an email from new PM's here.
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  #485  
Old 05-16-2012, 04:08 PM
CBK9811 CBK9811 is offline
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TGFPLY….

I am not an audiophile in its truest form. I don't get into measurements or have $1000 cables or anything like that. I listen to what I like, when I like and then I try to afford the best gear I can get my hands on. I have been in the market for a portable amp solution for a while now. I have read” just last night as a matter of fact all 104 pages of 1 thread on head-fi” about this amp and all the fuss it has caused.

I was about to purchase a Fiio small amp for my IEM’s and did a search for reviews and I got directed to ABI and I started reading and reading and more reading. I am first to admit I don’t get half of the parameters or specs that goes into measuring sensitivity or noise etc….

I don’t care. What I do care is if someone has a good design and is willing to help!! The “community” which I am a member of, I am not cheap. I spend Grrr like the next person on things I like and can get some appreciate level of joy out of. I have read countless reviews on RSA’s & Dr. Xin’s mini amps. I am sure there is a fair amount of fanboyism with any product. We are all guilty of this whether you like it or not. It's human nature and part of the day to day of commerce and being able to acquire cool stuff.

So when I ran across the 02 and the subsequent brouhaha it has caused I started reading as much as I could and from a consumer’s/hobbyist point of view. This is what I have interpreted to be what is being said of this particular piece of DIY.

1. It is being compared to Beta22, DAC1, GS1, TOTL
etc…

2. I have never heard any of those amp above. I may never in my lifetime. So I can not give an opinion on them. But my wallet can. If you are comparing a $200 piece of equipment with others that are in most cases easily over 1k amps then there is something fundamentally wrong. Either we are getting jobbed by the bigger manufacturers or the designer actually did an awesome design based on real world usability. It may not have have all the bells and whistles of the higher priced amps which is acceptable. But that's because of the price point and the portability of the amp.

3. It runs on batteries. Almost every amp it is being compared to runs power out of the wall socket.
Can’t put it in a backpack or a jacket pocket. And just clamp the cans on and roll out.

4. It cost $200 beans!!!! With charger and batteries. I can't even get a used RSA for that much $$ And to top it off its not even being compared to any amps that are triple its price point.

5. I know of another company coming out with an portable amp. And it will be well received by Head-Fi.
Or at least they will try to be as impartial as engadget is to Apple products. It will be interesting to see. how that plays out on the forums. I have seen the prototype and it looked cool. Hopefully the homie with the long hair comes out with something great he gets great reviews, people ears thank them and his company grows.

6. Like every consumer I will decide with my ears first and my wallet second, what i like or don’t. There are so many reviews of why it’s this or that. This particular hobby has a secondary market for a reason. It comes down to try with your particular equipment and with your type/state of hearing and see if you actually like the sound. I am into car audio and have a love/hate relationship with that hobby and the people who either speak the gospel of certain products or have an axe to grind against some other product.

I don't care either way I want what sounds best to to me. I have heard some outrageous cars and they sounded great to me and heard some cars that are IASCA winners and were not that impressed. I listen to everything from classical to reggae to rock to rap and everything in between. I have seen pretty much as much flame wars as I can remember and they all turn out the same. It all comes down to the individual and what sounds good to him/her.

7. Thanks for allowing me to join the amp club with your offering. If this experience goes well “sonically” and improves my listening enjoyment. I will once again use my wallet to make a choice and buy your new offering from JDS-Labs. And keep that as my computer rig.

Last edited by CBK9811; 05-17-2012 at 06:15 AM.
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  #486  
Old 05-17-2012, 02:03 PM
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You might want to check out my article:

http://nwavguy.blogspot.com/2012/04/what-we-hear.html

It explains why a lot of people, including those writing reviews at Head-Fi, hear what they hear. I'm working on a new article entitled Timex vs Rolex that discusses why there's such a wide range in prices, and provides a lot of tips on how to choose what gear is best for you.
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  #487  
Old 05-17-2012, 03:40 PM
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The DarkSide The DarkSide is offline
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Wow, I'll read through the tech section tomorrow. But, I must say, it's an excellent and well written article. It's this site, and the mods and members like you NwAvGuy, that kept me from becoming a blinded audiophile wannabe fool. I'm just a listener of music who knows what I like, and that it doesn't take XXX dollars to make everything sound better. You, sir, get my total respect!!!

tds101
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  #488  
Old 05-17-2012, 05:56 PM
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sYlt sYlt is offline
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Excellent article, I took a while to read it all since I'm a slow reader, and often give up midway, but the structure and the very interesting content compelled me to keep going, worth it.
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  #489  
Old 06-13-2012, 05:32 PM
Lesser Lesser is offline
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Hey Gents,

So I just got my ODAC+O2 combo from jdslabs as a present, but I need to get a power adapter, I'm really anxious to get listening to it so I was wondering if anyone might be able to help me out, the only AC adapter I can find locally (in the NYC area) is from Radio Shack (Enercell 18v 1000mA). I see in the recommended list from jdslabs that they have both an 18v (but at a 500mA), and a 1000mA (but at 15v). Would this still be a good option for my o2+odac? Or if anyone else has a suggestion of where I might get a better adapter in Manhattan.
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  #490  
Old 06-14-2012, 11:24 AM
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maverickronin maverickronin is offline
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That should just fine. The mA rating is just how much current it can deliver so it doesn't matter how high it is. The voltage rating is the one you have to worry about going over.

Just be sure to keep it in the 18V mode though. I forget what the absolute maximum voltage is before you damage anything but you should probably tape or glue the switch in the 18V position just to be on the safe side.
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  #491  
Old 06-14-2012, 02:50 PM
Lesser Lesser is offline
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Thanks for that. I just went and picked it up and it sounds great!
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  #492  
Old 01-28-2014, 05:10 AM
neutral neutral is offline
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If I understand correctly, O2 is a headphones only amp.

Or am I missing something and the title, O2: High Performance Portable/Home Amp suggests that it will power my home speakers as well?

Anyways, is it a good idea to have a 2 in 1, tiny, portable, home stereo + headphones amp? What comes close?
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  #493  
Old 01-28-2014, 06:02 AM
Enigmatic Enigmatic is offline
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Quote:
Originally Posted by neutral View Post
Or am I missing something and the title, O2: High Performance Portable/Home Amp suggests that it will power my home speakers as well?
http://www.anythingbutipod.com/forum...40&postcount=1:
Quote:
It's a very objective approach (what would you expect from an electrical engineer?) at a low cost "one size fits all" headphone amp.

Last edited by Enigmatic; 01-28-2014 at 07:16 AM. Reason: Fixed URL.
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  #494  
Old 01-28-2014, 05:48 PM
saratoga saratoga is offline
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Speakers tend to be lower impedance that headphones, so generally you can't use a headphone amp with them.
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