O2: High Performance Portable/Home Amp

[Urne]

Wow, that looks wonderful!

[CrowdAds]

[Moyt]

Damn I'm sooo close to jumping on the o2 bandwagon!

[NwAvGuy]

Originally Posted by The DarkSide

If there's anyone selling one of these FULLY ASSEMBLED in the USA please PM me,.... Thanks!!!

JDS Labs is selling a fully assembled and tested O2 board. From there you can just slip into the the enclosure and buy a ready made front panel from a few different sources. the latest details are always in the O2 Resources section on my blog (including a link to JDS).

Sorry I've been MIA here for a while. I was keeping an eye on the thread and didn't see too much that needed my input.

[johthor]

I might be incorrect but I believe JDS labs is offering a complete O2 for sale on their website.

I have just registered here after reading many posts by NwAvg. Your post and blogs are awesome. I am new to this hobby and had been wading through Headfi until I read you were banned there. Just wanted you to know many of us have banned ourselves from there.

Your contributions to the HIFI hobby are priceless. Thank you very much

[NwAvGuy]

Originally Posted by johthor

I have just registered here after reading many posts by NwAvg. Your post and blogs are awesome. I am new to this hobby and had been wading through Headfi until I read you were banned there. Just wanted you to know many of us have banned ourselves from there.

Your contributions to the HIFI hobby are priceless. Thank you very much

You're welcome. Thanks for the kind words. I just posted a new review of something a bit different (it's not an iPod at least )

[t2t]

I was able to get the face plate mounted on my O2 this afternoon. This is the face plate from the DIYAudio group buy that was conducted. Unfortunately, all of the face plates have been sold. They are a great face plate - beautiful, great fit, etc.

[nupi]

Being as happy as I am with my FiiO E10, is there much point in trying to hunt one down for Xmas? (hinthint, we'd love to see an E10 review, I honestly think it is the DAC to go for now :P)

[NwAvGuy]

@nupi, The E10 review will likely be in a few weeks (early January). The O2 can drive a lot of headphones the E10 can't. But if you and your headphones are happy with your E10 don't worry about the O2.

I'm curious if you've had any issues with the E10's headphone jack? Several have said the headphone plug doesn't fit tightly enough, there's noise when the headphone cable or amp are moved during listening, etc. Have you noticed any of those? I didn't notice any issues with the E11's jack when I reviewed it.

[ohmer]

That is a sweet rosewood enclosure. Wish I had a shop.

I've had a good experience driving my Beyer 250 Ohm DT990 PRO and I get no noise. I also don't have a problem with the plug being loose. I have 3 other headphones (one IEM) I have used with it and they work well.

It's great but I wish it had a line in option. Then I could power it with an external 5v battery for portable use.

[nupi]

Originally Posted by NwAvGuy

I'm curious if you've had any issues with the E10's headphone jack? Several have said the headphone plug doesn't fit tightly enough, there's noise when the headphone cable or amp are moved during listening, etc. Have you noticed any of those? I didn't notice any issues with the E11's jack when I reviewed it.

No issues with the headphone jack that I can tell (neither with my IEMs nor the D2000) - however, the EM shielding could be better, if my phone is communicating with the towers on GSM, I can hear the familiar 2600Hz buzz which really should not happen. Other than that, no issue that I can see.

As for hard to drive equipment, I currently do not have any (hell, the D2000 even sounds decently out of the Clip+ albeit a more powerful source definitely improves things a little) but I am toying with the idea of getting myself an LCD-2 but I fear this is another overpriced FOTM in the forum-that-should-not-be-named... Or maybe a HD600 but that beast keeps increasing in price

[t2t]

Originally Posted by nupi

... but I am toying with the idea of getting myself an LCD-2 but I fear this is another overpriced FOTM in the forum-that-should-not-be-named... Or maybe a HD600 but that beast keeps increasing in price

There's actually quite a few of us from over at HeadFi who have been going the Grado custom route with Magnum drivers. What were finding out is that we're getting a much smoother driver than the de-facto Grado. For anyone who might have been pushed away from the Grado sound in the past, they might consider taking another look at a setup based on the Magnum driver from Symphones. I think some people might be quite surprised. Plus, such a custom set up isn't that hard on the wallet, either.

[ov_Darkness]

It's very interesting amp. I think you've started something REALLY BIG @NwAvGuy!
I'll get myself a dekstop version PCB's as soon as they'll be available!

I'm thinking about something: is it possible to make O2 AMP in smaller factor?
Something really portable with ~20h battery life? Possibly Li-ion's recharged via USB?
The enclosure could be the smallest Hammond 1455C801
14500 (AA size) 3.7V cells are quite nice.
Using ALPS RK097 with built-in switch could render on/off switch useless - saves place.
There's many DIY'er out there, who have the skills necessary to solder SMD parts.

[nupi]

Originally Posted by t2t

There's actually quite a few of us from over at HeadFi who have been going the Grado custom route with Magnum drivers. What were finding out is that we're getting a much smoother driver than the de-facto Grado. For anyone who might have been pushed away from the Grado sound in the past, they might consider taking another look at a setup based on the Magnum driver from Symphones. I think some people might be quite surprised. Plus, such a custom set up isn't that hard on the wallet, either.

When I look at the Magnum page, that looks plenty expensive - I could definitely get a HD650 for less than the quoted 399 (much less buying the Grado first)...

[NwAvGuy]

@ov_Darkness, the Li-ion issue is complex and discussed extensively in the diyAudio O2 thread. The short answer is there's no safe and reasonably priced way to do it because of the O2's need for dual power supplies with relatively high voltage and the tricky charging requirements of Li-ion batteries. Look up "Lipo Fire" on YouTube for houses that have burned down, auditoriums emptied, planes making emergency landings, etc., all due to Li-ion battery fires.

Even the on/off switch isn't so simple. Because there are two power supplies, the O2 needs a dual pole power switch. Volume control switches are all single pole.

I'm guessing that "China Inc" might do with the O2 what FiiO did with the AMB Mini3 and their E11. They made it small, cheap, and Li-Ion powered using a DC-DC converter from a single 3.7V cell. The O2 would require a dual DC-DC converter. The price for an assembled amp Mini3 effectively dropped from nearly $200 to $65. It's hard to beat mass production in China on pricing compared with DIY.

[t2t]

Originally Posted by nupi

When I look at the Magnum page, that looks plenty expensive - I could definitely get a HD650 for less than the quoted 399 (much less buying the Grado first)...

No. No. Most of us are not using a pair of Grado SR-325i headphones for $299 and then having the Symphones' Magnum upgrade performed for an additional $399.

Instead, several of us are opting for a pair of the v.4 Magnum drivers from Symphones and installing them in our wooden-cupped Grados. The drivers sell for $120 a pair + approximately $20 in shipping. For about $300, you have have a "killer" set of headphones based on the Grado premise, but with a much more refined driver.

[nupi]

After shipping to Europe, that still is more than a HD650 and I doubt I like the Grado premise to start with...

[xnor]

Innerfidelity has some measurements of an older magnum driver and it's worse than an SR60i.. Maybe things improved with the v4 driver, but the driver is one of many parts in a headphone that need to be "tuned" to provide the desired frequency response, low distortion etc.

[maverickronin]

Grados are supposed to be colored as hell so you can't really judge them like that. The Magnum drivers would seem to keep the "good" parts of the color and make them more listenable with less ringing in the driver according to these CSD plots.

[saratoga]

Originally Posted by NwAvGuy

As for the desktop amp, I'm still hoping to have something published before the first day of winter. Right now I'm waiting on information regarding a possible DAC board to pair with it as an option for those wanting an integrated DAC and headphone amp.

Looking at your reviews again, I think we really need to see about getting that Clip+ USB audio driver working. The relatively good output compared to other USB DACs coupled with the very small size would make it a good choice for driving an external, cost effective amplifier.

I hadn't realize the available USB DACs were so average, at least without spending quite a bit.

[Marvin the Martian]

Originally Posted by saratoga

Looking at your reviews again, I think we really need to see about getting that Clip+ USB audio driver working. The relatively good output compared to other USB DACs coupled with the very small size would make it a good choice for driving an external, cost effective amplifier.

I hadn't realize the available USB DACs were so average, at least without spending quite a bit.

Are you referring to an actual line-out signal through the USB connection? That would thrill a lot of people, although in all fairness I think the headphone-out still does a pretty decent job with an amp.