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Old 26th January 2012, 01:38 PM   #1931
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I for one would like to again put in a big "thank you" to RS and others who made the group buy(s) happen. I've really been enjoying my O2 the last month or so and am really looking forward to the ODA/ODAC build coming up. I'm also saving my pennies for some HD-700's, which I think the O2 should handle nicely.

I too have been amused by some of the O2 reviews by subjective types. Generally good reviews, but usually reluctant to put them ahead of much more expensive amplifiers (even without AB testing).

But I'm with RS when it comes to subjective reviews: without some kind of direct comparison (ABX or blind AB), I don't think they're worth much. I would be incredibly impressed if anyone could truly tell this apart from another good, low output impedance, FLAT (i.e. non-tube) amplifier that has a similar noise floor (noise can be a dead giveaway). I have yet to see anyone do that consistently. I swear some of these guys just make stuff up to have something to write.
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Old 26th January 2012, 02:13 PM   #1932
Davey is offline Davey  United States
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Quote:
Originally Posted by FloridaBear View Post
B), I swear some of these guys just make stuff up to have something to write.
The VERY definition of subjective evaluation. Well put.

Cheers,

Dave.
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Old 26th January 2012, 08:57 PM   #1933
Angkor is offline Angkor  United States
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Hi Everyone,

I made my second 02 amp with a gain of 1x and 2.5x in mind, so i soldered resistors R17 and R21 to positions R19 and R23, respectively, and left R17 and R19 empty on the PC board. I plug in my headphones and there's a channel imbalance. Would this have anything to do with me repositioning the resistors?

After messing with it a bit I found that wiggling the input jack up and down would cause it to go in and out of balance, but when left alone, it's defaulted as imbalanced. I'm suspecting this to be the culprit.

Note on Imbalance: It sounds like the left channel gain is working fine; I hear a difference in loudness switching from low to high gain. The level of loudness on the right channel stays the same regardless of the gain setting, think its stuck on the high gain.

Has anyone experienced a similar problem? Any advice on fixing this? Any help is much appreciated.
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Old 26th January 2012, 09:15 PM   #1934
Angkor is offline Angkor  United States
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correction: R17 and R21 are left empty on the board, not R19. Sorry about that...
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Old 26th January 2012, 09:26 PM   #1935
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Is the corner of the gain switch touching the feed-thru via?
If not, reflowing the solder joints of the input jack couldn't do any harm.
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Old 27th January 2012, 08:28 AM   #1936
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Quote:
Originally Posted by FloridaBear View Post
I for one would like to again put in a big "thank you" to RS and others who made the group buy(s) happen. I've really been enjoying my O2 the last month or so and am really looking forward to the ODA/ODAC build coming up. I'm also saving my pennies for some HD-700's, which I think the O2 should handle nicely.

I too have been amused by some of the O2 reviews by subjective types. Generally good reviews, but usually reluctant to put them ahead of much more expensive amplifiers (even without AB testing).

But I'm with RS when it comes to subjective reviews: without some kind of direct comparison (ABX or blind AB), I don't think they're worth much. I would be incredibly impressed if anyone could truly tell this apart from another good, low output impedance, FLAT (i.e. non-tube) amplifier that has a similar noise floor (noise can be a dead giveaway). I have yet to see anyone do that consistently. I swear some of these guys just make stuff up to have something to write.
Hmmm, I don't agree with that sentiment at all.

I don't want to comment on the O2's sound quality here, but I think it's important to note that subjectivity is the ultimate judge of ALL audio equipment. If you don't trust your ears, I think you're missing the point of listening in the first place. As one person put it so bluntly "customers don't listen with their scope."

I agree that if people make outrageous claims they should back them up with some data. But if someone simply relates their opinion, it's hardly the case that you can just write it off in the manner you have. The point of relating experience on a forum like this is to build a consensus, it's how sites like Amazon leverage a community to produce a real understanding of how a product performs.
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Old 27th January 2012, 02:09 PM   #1937
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Originally Posted by imminentdomain View Post
Hmmm, I don't agree with that sentiment at all.

I don't want to comment on the O2's sound quality here, but I think it's important to note that subjectivity is the ultimate judge of ALL audio equipment. If you don't trust your ears, I think you're missing the point of listening in the first place. As one person put it so bluntly "customers don't listen with their scope."

I agree that if people make outrageous claims they should back them up with some data. But if someone simply relates their opinion, it's hardly the case that you can just write it off in the manner you have. The point of relating experience on a forum like this is to build a consensus, it's how sites like Amazon leverage a community to produce a real understanding of how a product performs.
I don't write off subjective listening, but I do believe it needs to be done in a blind AB setting in order to be of any value. The idea of sighted subjective listening is way too biased in my opinion. I would definitely give weight to a properly level-matched ABX test where there were significant differences reliably detected. The brain is just too unreliable otherwise.

But we're getting off-topic here and this has been discussed ad nauseum in countless other threads I'm sure.
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Old 27th January 2012, 02:18 PM   #1938
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That ODA(C) must be very good. Has been a long time since we heard from RS. To busy listening I guess.

Here a nice comment on headfonia about the O2:
Quote:
headfonia.com
One thing I noticed this time with the JDSLabs O2 is that this amplifier has got to have the lowest noise floor I've heard on any headphone amplifiers, from the tiny little RSA Shadow type amps to the big $3K desktop amps. Battery power are good for these kind of things, but the funny thing is that I've listened to tons of battery powered amps and still have yet to hear anything with a clean black background like the O2. I'm just talking about one element of the sound though, doesn't mean that the O2 is suddenly better than the bigger amps.
woensdag om 9:29
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Old 27th January 2012, 06:19 PM   #1939
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Hey, I got my O2 headphone parts from mouser.

Where can I find the parts list? I need to know where to stuff these parts.
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Old 27th January 2012, 06:30 PM   #1940
MrSlim is offline MrSlim  Canada
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Let me Google that for you.. NwAvGuy: O2 Details
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