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Posts by tomb

OMG.  Mayflower.  That explains a lot.  Sorry I didn't know this when I replied to your PM's. One thing you might check right away are the power connections to the PCB from the IEC inlet.  Mayflower was known not to put in all the mounting screws (among other things) and the IEC inlet pins would break in shipment.  You may need to supply some more pics - especially around the power inlet and underneath the PCB - before we can confirm it's even safe.
  Yep. The PCM2706/7 should not be an issue, either.  The issue with the PCM2707 is lining it up on all four sides with the pads.  If you get it wrong, you can re-position it.  Just make d*mn sure you don't solder a second pin until you're completely satisfied that all the pins on all four sides are lined up.
waki-hypnotism?   Of course jcx makes some good points.  He always does.  You didn't, though.  There's another side to the issue - always has been.  It's some people who try to slam the lid on that that make the offense.   Here's a question - have you ever built a 3-channel amp?  Compared it to the same version with two channels? Tried to tell the difference?  Shorted out the active ground and noticed the effects?   Just some questions while you're busy clicking...
 I disagree; the reasons are many.  It's not marketing when there are better measurements and better reports from actual owners and builders.  Challenges such as yours are usually the tool of the inexpensive-equipment proponent and are often a method to justify your own investment.*  Saving money is admirable goal, but it's wrong to dismiss an entire industry by implying it's simply wasting its time by providing better products.  Yeah, there's marketing - plenty of it, but...
You're "not here to argue numbers" but you want a "bias-controlled listening test?" and mention "audiophile myths?"  Forgive me, but that sounded a bit troll-ish and that's the reason I responded.  No offense, but the statement, "a headphone amp is basically an inexpensive chip" sort of explains your position.
Might I suggest a Grado?  The RS-1 or PS500 might be something you'd like.  The signature is as close to AKG K/Q701's as any other on the market.  The difference being that the Grados are not so "clinical" and have decent bass punch.  Grado's are fantastically "musical" compared to the dry detail in the AKG.  I own both K701 (original low-SN Austrian version), K712, and Grado PS500's.  I've also spent extensive listening with RS-1's.  I think if you want a little less...
Most have built-in headphone connections, but that doesn't mean they have a dedicated headphone amp.  There's a difference.  Some take a huge shortcut and simply apply a high-current-limiting resistor to the speaker amplifier output.  The results are less than satisfying with a quality headphone.   The problem is that you can't tell - it's not something in the normal spec sheet for a receiver or integrated amplifier.  Many pre-amps have quality headphone outputs, but...
There is no such thing as a "virtually perfected technology."  What you are trying to say is that the actual implementation of the DAC circuit is very important.  Even then, there are sometimes huge differences between DAC chips themselves.  If not, people wouldn't be clamoring to use ESS DAC chips, Wolfson, or any other brand that may have its fans. As for cell phone output impedance, yes - it can have an effect, but many cell phones these days have output impedances<1 -...
 There's a very easy way to tell when you build one.  Simply temporarily short the output ground channel to chassis ground.  You can do this by simply connecting the headphone jack's ground to chassis ground. That will take the active ground channel out of the circuit.  The difference in the sound of the amp is night and day.  It's one of the things you must do when building one - be certain the output ground is isolated from the chassis ground for proper operation of the...
Most experienced B22 builders seem to agree that there's no benefit with the active ground channel in a balanced configuration.  Despite what some say, the third channel in a single-ended configuration is much more debatable.  You have to know how to measure one to get truly valid results.  Many don't.  
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