Quote:   I find that on the proper source and amp the Q701 has holographic imaging that is stable and multi-layered. Beats the pants off the HD650 in this regard. ;)

Quote:   Did people enjoy music less in the 70's and 80's?    The key thing to realize is that we identify sound as objects (words, people, animals, etc), and that essentially 99% of our use of sound is for communication. Music is a form of communication, the notes bear a meaning just...

Q701 is a great headphone that even has some HD650 like qualities in the bass region. In fact, overall I'd rate the bass performance above the HD650's, but with the caveat that the overall bass presentation and quantity is better in the HD650's. Bass is more tuneful and well defined on the AKG's...

Quote:   Studies have been done in the past and musical enjoyment is not really related to sound quality. Is that what you're getting at? 

No, not really. I'd say the O2 is average at best. Some people are very sensitive to treble, some aren't, personally, I couldn't listen to the O2 for extended periods as it's too bright. I find that it colors the sound towards the bright side of things. The O2 is a strange amp and rather than...

Anyone know a release date?

I'm sure it depends largely on what headphones you hook up to the thing, but I am unequivocal despite Willikans arguments, the O2 has that faux transparency that is common of low end high-fi gear that is trying to hard. The O2 also behaves very differently depending on the headphones, in other...

Looks like I spoke too soon. While the RC filter definitely reduces the temps the v-regs reach, after leaving the amp plugged in for a full 24 hours the sound regressed towards the oomphless smeary sound I've become so familiar with.. The v-regs are still reaching close to 50C, and at those...

If anyone has a uDac, the knob fits perfectly.

Over on DIYaudio one mod that was posted is implementing a CRC filter on the bottom of the board under the power supply caps. I implemented an RC filter and this resulted in significant increases in the performance of the amp. Previously the amp had that harsh top end and was distinctly thin and...

  Quote: The wall plug shows 18.1v C2 & C3 show 24v U5 & U6 show 24v on the input & approx 12v on the outputs.              

  Quote: I basically agree with your view. My issue is that I've built two of these, and I've heard the amp's output quality degrade after 1-3 hours on both of them, depending on ambient temp, volume, input levels, and headphones. From my experience with electronic devices if...

  Quote: I will be doing a comparison between the O2 and The Wire at least. 

  Quote: I'll get around to it, unfortunately I do have more pressing matters at the moment.   I also want to look over the mods being posted on diy audio and try some that I think may affect sound quality (in my totally unprofessional opinion).   Once I've completed my modded...

  Quote: Just because he isn't that person doesn't make the amp not that amp.

  Quote: Part of the reason why you folks piss me off so much is because I explained this (and many other things) in detail like 6 times in this thread. I stated unequivocally, I was WRONG before. Not to mention, the amps performance degrades over time due to sissy v-regs...      

    Quote: I have two properly built amps thank you very much, they're both noise free, and perfectly functional within the scope of the limitations in their design or parts.      

Quote: I had a change of heart and decided to be nice to all of you, ignorantly going on and on about how great this amp is and let you live in your profound ignorance. 

  Quote: My god man, can you read? Look at my sig: GRUBDAC.  LOL.

  Quote:   LOL, live in ignorance, I could care less, you want to believe in the magic of the PDF datasheet amplifier connected by a volume pot to a wikipedia article's output stage, more power to you.    

  Quote: Semiconductors *are* very fragile. You may heat one up and find it works because they're designed to withstand heat. But long before the IC completely burns up, it will suffer reduced performance characteristics, permanently if it is heated up too much or for too long.  ...

  Quote: Why is that interesting? It's an idiotic challenge, I don't want to donate $500, I want to WIN $500. If I was going to pocket $500 I would do it right now.

  Quote: I mean that in REW, under 50hz, the FR curve is all over the place on the stock amp, and tightly controlled down to 20hz on the modded amp.   And yes, the regs get hot... I'm not sure how anyone could use the WAU16-400 and not feel that the regs are a tad hot, though they...

I finally got around to A/B'ing my "modded" O2 with my semi-stock O2 and I was able to easily pick out the two amps in a blind comparison with matched volume levels. The only things not-stock on the the semi-stock O2 are the power supply caps, and the mosfets (I switched everything else back to...

Quote: Nothing is "buggered-up", what is wrong here is that this linear half wave power supply has gnat balls when HD650's require swinging truck nuts to sound their best. Sure some of you think it sounds clean and clear or whatever, but I feel you're not true connoisseurs of HD650 sound...