Review: JDS Labs O2 (Black edition) + O2/ODAC discussion
Dec 13, 2013 at 11:38 AM Post #466 of 543
If you want to muck around with the O2 there is only one real person that I know of that has had success in this area....take a look at
agdr posts here: http://www.head-fi.org/t/693300/o2-headamp-output-booster-modification-pcb#post_10037386
 
Also take a look at the DIY Audio site under headphone amps and there is a quite in depth discussion about this amp, its design, and lots of stuff.
 
Alex
 
Feb 5, 2014 at 7:30 PM Post #467 of 543
  iCan: 400mW of output power (@32 Ohms)
O2: 613mW of output power (@33Ohms)
 
so the O2 puts out more power, i already know that. But power isn't everything.
 
Not my review:
http://noblehifi.blogspot.co.uk/2013/05/ifi-ican-review.html
 
But mine is the new version with adjustable gain.


Ostewart,
 
I'm considering this Amp but I'm a bit concerned as I'd be using it for an already neutral headphone (Shure SHR 840) so it has me wondering if I should find a similar priced TUBE amp to warm things up and bring out the bass?
 
I'm looking for something to connect to my Oppo 95
 
Feb 5, 2014 at 7:35 PM Post #468 of 543
The SRH840 are a little on the warm side so the O2 would sound great with them. If you want a budget tube amp, the Bravo Ocean would fit the bill.
 
Feb 5, 2014 at 8:20 PM Post #469 of 543
Thanks Ostewart.
 
Yes, I bought the 840's because they seemed to have the best balance of clarity and warmth so I can use them for mixing AND listening.(In my price range)
 
Which would be the better choice to bring out the bass making the cans fuller and warmer for movie and CD listening?
 
Feb 6, 2014 at 10:06 AM Post #471 of 543
The Ocean has an output impedance spec of 20-100 ohms...wow that's going to affect the bass dept.
 
If you want good controlled tight bass this is not the amp to look at.
 
Its cute, small and inexpensive...it runs HOT!..
 
I would get the O2 amp and if you really want to warm up things just EQ via your player software...
 
All the best and good luck..
 
A. 
 
Apr 15, 2014 at 11:16 PM Post #475 of 543
Hey guys, would this unit be powered sufficiently by 2.0 USB ports? Or will I need to supplement it with an externally powered USB hub? 
 
Also, I'm wondering if I will have any issues (distortion, clipping, funny noises, problems with operation, or any problem possible) plugging this thing into my power bar? Or should I just plug it into the wall socket? And if I plug it into the wall socket can something else be plugged into it as well? 
 
Like, ya know how there are two sockets, one above the other, would using BOTH sockets (one for my odac+o2 and one for my power bar that runs my computer and stuff) be a problem? 
 
I'm just being super extra double sure with all these questions before I drop 300 bucks :p 
 
 
Also, this thing is neutral, and transparent right? 'Cause, that's why I'm interested in it. 
 
Edit: Does it matter if I get the headphone jack to be the 3.5 or the 6.5? Is there any difference in performance? I was also thinking I'd get the gain options at 1X & 2.5x. The 1x would be for my KRK KNS 8400 and the 2.5x would be for when I get the HD600. Thing is, I heard that if you don't raise the volume past 10'oclock on this thing there is a channel imbalance. So, a 2.5x would be too strong for my not-so-hungry KRKs. But it'd suit the HD600 nicely. Correct me if I'm wrong! :) 
 
Apr 16, 2014 at 12:32 AM Post #476 of 543
I see that jds labs o2 have socketed op amp ...is those rollable ?? So I can change the op amps ?

Yup, op-amp rolling is possible.


Hey guys, would this unit be powered sufficiently by 2.0 USB ports? Or will I need to supplement it with an externally powered USB hub? 

Also, I'm wondering if I will have any issues (distortion, clipping, funny noises, problems with operation, or any problem possible) plugging this thing into my power bar? Or should I just plug it into the wall socket? And if I plug it into the wall socket can something else be plugged into it as well? 

Like, ya know how there are two sockets, one above the other, would using BOTH sockets (one for my odac+o2 and one for my power bar that runs my computer and stuff) be a problem? 

I'm just being super extra double sure with all these questions before I drop 300 bucks :p 


Also, this thing is neutral, and transparent right? 'Cause, that's why I'm interested in it. 

Edit: Does it matter if I get the headphone jack to be the 3.5 or the 6.5? Is there any difference in performance? I was also thinking I'd get the gain options at 1X & 2.5x. The 1x would be for my KRK KNS 8400 and the 2.5x would be for when I get the HD600. Thing is, I heard that if you don't raise the volume past 10'oclock on this thing there is a channel imbalance. So, a 2.5x would be too strong for my not-so-hungry KRKs. But it'd suit the HD600 nicely. Correct me if I'm wrong! :) 

Yes, the ODAC is meant to be powered via USB 2.0. Unless your USB ports don't supply enough power (one of my ports on my old MacBook has this issue), then a powered USB hub may be necessary then (or you can just try another USB port).

Power bar and/or wall socket should be fine I believe. I would be worried if multiple-socket plugs weren't able to handle more than 1 device. With the O2 at 6.3x gain, you might hear clipping/distortion, but that's not because of the power, it's because of the amp design itself.

Yes, the ODAC and O2 were built to be transparent when compared/blind tested to a DAC-1 Pre.

No it doesn't matter which socket you use. Channel imbalance only occurs at low volume levels of the potentiometer (9 o'clock or lower-ish) because that's inherently a problem with pretty much all analogue volume potentiometers.
 
Apr 16, 2014 at 12:36 AM Post #477 of 543
Yup, op-amp rolling is possible.
Yes, the ODAC is meant to be powered via USB 2.0. Unless your USB ports don't supply enough power (one of my ports on my old MacBook has this issue), then a powered USB hub may be necessary then (or you can just try another USB port).

Power bar and/or wall socket should be fine I believe. I would be worried if multiple-socket plugs weren't able to handle more than 1 device. With the O2 at 6.3x gain, you might hear clipping/distortion, but that's not because of the power, it's because of the amp design itself.

Yes, the ODAC and O2 were built to be transparent when compared/blind tested to a DAC-1 Pre.

No it doesn't matter which socket you use. Channel imbalance only occurs at low volume levels of the potentiometer (9 o'clock or lower-ish) because that's inherently a problem with pretty much all analogue volume potentiometers.

Cool, thanks for the response! So, by transparent, you mean neutral as well? 
 
Also, would you suggest I stick with the 1x and 2.5x gain then? 
 
I desperately want this unit. I am really, really excited to move beyond my clip zip. I've heard the improvement is very noticeable. 
 
Apr 16, 2014 at 12:49 AM Post #478 of 543
Yup, op-amp rolling is possible.

Yes, the ODAC is meant to be powered via USB 2.0. Unless your USB ports don't supply enough power (one of my ports on my old MacBook has this issue), then a powered USB hub may be necessary then (or you can just try another USB port).

Power bar and/or wall socket should be fine I believe. I would be worried if multiple-socket plugs weren't able to handle more than 1 device. With the O2 at 6.3x gain, you might hear clipping/distortion, but that's not because of the power, it's because of the amp design itself.

Yes, the ODAC and O2 were built to be transparent when compared/blind tested to a DAC-1 Pre.

No it doesn't matter which socket you use. Channel imbalance only occurs at low volume levels of the potentiometer (9 o'clock or lower-ish) because that's inherently a problem with pretty much all analogue volume potentiometers.

Cool, thanks for the response! So, by transparent, you mean neutral as well? 

Also, would you suggest I stick with the 1x and 2.5x gain then? 

I desperately want this unit. I am really, really excited to move beyond my clip zip. I've heard the improvement is very noticeable. 

Er, I should have said neutral instead of transparent. In terms of audio, transparent means the audio system sounds realistic (as if the sound is coming from a live performance rather than a speaker or headphone) whereas neutral just means not coloured. A system can be neutral but not transparent and vice versa. I almost never use neutral since I don't think it's possible to have uncoloured audio unless you were the original mastering engineer and you know exactly what the music is supposed to sound like.

I have the O2 at 1.0x and 2.5x gain, so yup! :D
 
Apr 16, 2014 at 9:58 AM Post #479 of 543
  Cool, thanks for the response! So, by transparent, you mean neutral as well? 
 
Also, would you suggest I stick with the 1x and 2.5x gain then? 
 
I desperately want this unit. I am really, really excited to move beyond my clip zip. I've heard the improvement is very noticeable. 

I advocate keeping the 6.5X gain - it comes in handy when using 1V (or less) sources and HDR recordings (Live music, Movies, some Video Games). Particularly if you are using the O2 with headphones in the 90 dB efficiency range. If you think that will NEVER be the case, unity and 2.5x will probably be great.
 
Remember that if you wanted, you can use the windows volume control (for example), you get your levels where you want them with whatever phones you are using. Also, you can take the O2 from 2.5X to 6.5X to 1X, 2.5X if you want, but you can't "add" gain later!
 

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