O2: High Performance Portable/Home Amp

[Shike]

So, have we figured out what the price is going to come in at roughly for straight DIY? I think even I might pick up a soldering iron and give it a shot if it's reasonable and doesn't scream of high difficulty.

[CrowdAds]

[mikeaj]

Originally Posted by Satellite_6

Come forth to ABI, NwAvGuy's minions.

Hi, NwAvGuy minion reporting in. :P

I like the site and have been here before, but I couldn't remember if I had an account, so I just created one.

Originally Posted by Shike

So, have we figured out what the price is going to come in at roughly for straight DIY? I think even I might pick up a soldering iron and give it a shot if it's reasonable and doesn't scream of high difficulty.

I've soldered various pieces and components together on protoboard, and it's really not that hard. The through-hole stuff should be pretty reasonable to do. As usual, the "third hand" and an iron with a thinner tip would be helpful.

Surface mount components are ridiculous though. I've said it before, but I'm glad there's none of them in the design. Supposing you have the visual acuity to see the little buggers and where they need to go, good luck creating solid solder joints without some specialized tools and training in secret ninja arts neurosurgery.

[razorblader]

Very interesting project NwAvGuy, I'm following your blog now as well.
Thanks for making this 'open source' and all the technical information that you provide. Solid engineering all the way, kudos.

[Anonanimal]

Hey all! Just wanted to check in and say I also set up an account here to follow this intriguing project. I look forward to building one of these when the time comes!

[korn_thoughtless6]

$30!!! seriously?

[NwAvGuy]

Originally Posted by korn_thoughtless6

$30!!! seriously?

Yup, $30 (plus shipping costs & some DIY time) will get you a fully functional PC board. If anyone has any questions, please ask? Comments, feedback and suggestions are also very welcome.

[axon01]

Originally Posted by NwAvGuy

Yup, $30 (plus shipping costs & some DIY time) will get you a fully functional PC board. If anyone has any questions, please ask? Comments, feedback and suggestions are also very welcome.

What do you think a populated board will cost?
How about a wild guess?

[WalkGood]

@NwAvGuy I’d like to make a suggestion as long as dfkt is in agreement or if he has another suggestion I’m sure he’ll post it. In order that the ordering information is not buried in this thread once you have it altogether. Start a new thread in the “Classified” section titled “O2 DIY Amp Order Information” or something like that and have it back linked to the first post here. Keeping the discussions here and the order info in the other thread makes most sense to me, hope others agree.

[rroseperry]

I think I could be interested in the preassembled board approach since I've never held a soldering iron and am pretty sure I don't want to practice on this.

[The Larch]

Originally Posted by NwAvGuy

Did you find the bits about the same board slipping into a taller aluminum case allowing adding 1/4" headphone jacks, RCA inputs, etc? I'll be making the CAD file(s) available for that version as well. You can just send them to Front Panel Express as is, or you can add your own tweaks, lettering, etc.

I'm curious if there's any sort of consensus on what people would like in the bigger version?

1. RCA inputs on the back (even though that means ordering two panels instead of one doubling the cost)?
2. Two 1/4" jacks instead of just one (in addition to the 3.5mm jack)?
3. Install the board "backwards" to put most everything on the back and just have a panel mounted "off board" volume control and 1/4" jack on the front?
4. For option #3 above, can the power switch stay on the back? (the O2 idles at 0.5 watts power and can be left on 24/7).
5. Also for option #3? does the front need a panel mounted Power LED?

Yess to a 3.5mm jack and a 1/4" jack. I don't care if the inputs are on front or back same with the switch.

[Limp]

It becomes increasinly obvious to me that I need a new soldering iron.

V. imressive stuff, Nw (not that I understand half of it )

[dfkt]

NwAvGuy, I put you on the front page: http://anythingbutipod.com/2011/08/o...headphone-amp/

If you find any errors in the descriptions, please let me know.

[saratoga]

Very impressive analysis.

[NwAvGuy]

Originally Posted by dfkt

NwAvGuy, I put you on the front page: http://anythingbutipod.com/2011/08/o...headphone-amp/

If you find any errors in the descriptions, please let me know.

@dfkt, it looks great! I'm flattered and appreciate the exposure for the O2. The tiny snowball is starting to roll down the snow covered hill I think

@walkgood, that's a good idea. As soon as one of the interested vendors has something to order, I'll start a thread in the classifieds section (or someone else can).

@Limp (and others), thanks for the encouragement. There might be lots of technical stuff in the three articles, but it's all just the "behind the scenes" stuff for those who are interested. What ultimately matters is you can get better performance than lots of other products and designs are offering for a lot less money. The whole point of the O2 is to raise the bar in ways that nearly everyone will ultimately benefit from.

[jupitreas]

I find this whole endeavor very interesting and worthwhile. Not being an engineer, I don't think I'd be able to build one of these myself, as relatively easy as it might be. I will certainly consider buying one of these if some good company that is endorsed by NwAvGuy starts selling them though.

NwAvGuy, I really enjoy reading your blog and I really think that such a voice of reason is needed to dispel the very many scientifically-unfounded myths that exist in the world of hi-fi.

[NwAvGuy]

Originally Posted by jupitreas

NwAvGuy, I really enjoy reading your blog and I really think that such a voice of reason is needed to dispel the very many scientifically-unfounded myths that exist in the world of hi-fi.

Thanks Jupitreas! That's what I'm aiming for. I've managed to burn a bridge or two along the way, and can't say I'm the most tactful person around, but the goal is to bust some long-standing myths and provide more objective information to help anyone interested decide what they want to spend their money on.

[Urne]

A contribution like this should certainly be well received. I have never had the need of an amp, but if I do, this is bookmarked.

I have one question. Is more battery power consumed when the amp is used at higher volume?

I have no knowledge of this subject <- I hope that's enough to excuse any unintelligent question from me!

[NwAvGuy]

Originally Posted by Urne

I have one question. Is more battery power consumed when the amp is used at higher volume?

Yes there is more battery power consumed at higher volumes. That's true of any battery powered amp unless it's true Class-A. But I don't know of a single Class-A portable amp (which would generally have horrible battery life).

In the standard O2 the power delivered to the headphones has a relatively minor effect on real world battery life. In the low power (long battery life version) it has a larger relative impact. It's related to the headphone impedance, headphone sensitivity, listening volume, and the type of music (how compressed or dynamic it is).

[maverickronin]

The Just Audio AHA-120 is a class A portable amp. It has a bias switch so you don't have to beat the batteries to death any faster than absolutely necessary.

No idea how well it actually works out in practice...

[dfkt]

Some HiSoundAudio and Rocoo/Hippo players claim to be class A as well... I wouldn't trust them as far as I can throw them. Not that inefficient class A is bad in general, just a weird thing for portable audio.