Thanks! Will do.

No new cable yet - there are some good ones out there. Many moons ago, I looked for SMC cables and figured I'd just make my own. But they were surprisingly hard to find!

Mine are back in rotation after a long, long break. Forgot how awesome they can be (despite comfort issues and a cable that's slowly falling apart). These days I'm running Equalizer APO through windows and I used it to tune these to the Harmon Curve, with the exception that I run the bass a...

My O2 is going strong after, I don't know, 5 years or something? The original batteries are shot but it runs off the adapter just fine. Solid-state electronics usually are rock solid when and if they don't blow up early in their lives. I have AV receivers and other audio gadgets that are over a...

Search back into this thread for information on how to mod them in ways that can improve the sound somewhat at a reasonable cost. I use the velour pads and a little bit of "sorbathane" - 40 duro, which cleaned up the midrange "congestion" enough to make these even better. A little EQing - 50 hz...

How Much Power do you need? There are products from Fiio that may also work just fine and they are not that costly. IF you can go without portability, there are good options that are affordable. The Schiit Fulla is about $100, AMP+DAC, for example. Not SUPER powerful, but more than enough for...

That is a nice flat line. When you read the reviews of "high end" (e.g. ridiculously expensive amps), the distortion is often not the same across frequencies. Notably, the midrange-treble areas may be the area where you see rising distortion at power (though, typically, max power or high power...

What I mean is that the distribution of harmonic distortion and its so-called "masking" effects might be subjectively pleasing to some, or all listeners of an amp. Amp distortion might create some "character" that is subjectively pleasing. Solid state amps with low THD sometimes get there with a...

There was an article online recently suggesting that "2nd order distortion" makes good amps sound great - since apparently even-order distortion is pleasant and odd-order distortion is not. It would be fun to find a way to test that hypothesis on my own, but for the article a dedicated piece of...

Not to be defensive or anything, but are you sure the clipping your hear is from the O2 / ODAC and not the recording itself? The combo has always been revealing enough to make recorded clipping audible through a pair of sensitive headphones (like planars). Tons of my music, whether CD or not...

So I stand by what I said! It seems to be a known issue to them, and they are willing to deal with it. I'm glad JDS Labs is helping you fuss-free. This is why they rock!

Where are you getting the data for this interesting fact: "0.5% of the population with a USB drive that makes the revA go unstable?" Please let me know what the size of the population is, or how you in anyway know this and aren't making it up for the sake of questioning my diagnosis. No, I don't...

Sounds to me like you might actually have a dying / dead ODAC. I don't think that the first revision of the ODAC was super-reliable, mine died after a couple of years and had the same L-channel cut out, then a tap might bring it back etc. I'd wager that the amp itself is fine, but the ODAC is...

It doesn't make a ton of sense that the O2 would be better at powering dynamic, as opposed to planar drivers. I own both. They both sound great. The HE-400s are much improved on the O2, since they are the least efficient cans I've played with on it. I think planars might be a little harder to...

The reality is that most headphones require, at most, just a few mWs of power to CRANK. when 1 mW can yield 90-100 dB, frankly, the power requirement is too low to justify a dedicated amp. That is why, frankly, most of my midrange cans sound just fine on a modern smartphone. Its the higher...

Basically, my hunch is that you should seek another O2 before subjectively OR objectively concluding that the Soundblaster AE-5 is superior - and that its superiority is plainly audible. To prove that, I would seek out a neutral 3rd party, and A/B the amp+DAC for them. It won't conclude WHY the...

What is direct HP mode? What is "directo Mode"? What was the source for the O2 measurements? The amp should be showing approximately 115 dBA for the noise level. The creator claimed upwards of 130 dBA at full output. With an ODAC hooked up my guess is it would drop to about 103 dbA with up to...

You can trust your own ears, but I don't have to. A proper subjectivist would simply have claimed that they preferred the sound of the AE-5 to the O2, then make some claim like, "because the soundstage was better" and "separation" was superior to particular listening tastes, environment, and...

In that case, I would probably do 1X gain for the IEMs and the 3.3X gain for less efficient cans. My computers have sounded really good, so the O2 will do its thing just fine. But I would note that the ODAC or an equivalent DAC definitely upgraded my sound nicely (I'd say 10% better though - not...

What amp did you think sounded good with those thin-sounding headphones? IMO the HE-400 sounded pretty bad until about 2 weeks in, when my ears adjusted. The amp had nothing to do with it except that I could go louder.

Short answer, Yes. For IEMs, many of which needing little power, I would say it is but I would get "unity" gain (gain of 0X). For most listening, 2.5X gain is good IF you have a 2V source. for a 1V source, like a phone / Mp3 player, I would want a little more gain.

I'd think that the Fiio would be enough power for sane listening levels. But if you are looking for something inexpensive that can hit high SPLs the O2 by JDS Labs will get it done and sound great (about a half-watt with little to no distortion). That is what I have used for years and I have...

I still love my HE-400s. I've been listening to regular speakers for quite awhile, since I figured I don't use them enough. The HE-400s still produce satisfying bass, and let me "peer" deeply into recordings in a way my speakers just can't. Or I guess the more oft used term is "instrument...

Sometimes the best way to learn is to just buy the best (or worst or just cheapest) tube amp you can find and see if you can figure out its contribution (or distortion) to the music you like. Then spend more money on different tubes seeing if you can hear a difference between them.   You can...

  Wow - Its great to see such a detailed and somewhat "critical" review of the O2. Thanks for the links.   The "dramatic rise" in THD at higher output powers is basically true of any amp - they all have their "sweet spots", and they also sound like s*** when playing out of their performance...