[286963]

I don't know how they engineer these headphone amps.
How do you guys know whether ur amp has defect/ does not perform as it should be (in minor stage)? 

 

[kramer5150]

Hmm no replies?  my general stance has been if it sounds good then it IS GOOD.  I don't think there really is a way to tell though.  Unless you can hear the difference between (say) .05% and .07 THD, slew rates... and other various parameters that are beyond what 99.9% of the population can hear.
 
DC offset can be measured with a good meter:
http://www.rock-grotto.co.uk/dcoffset.htm
 
A competent tech could meter/measure/scope various points in the circuit through the gain stages and ground returns.  There are also very sophisticated ways to measure EMI/RFI.

 

[Mak333]

I don't have much to contribute in the way of information to this thread... but thought it would be nice to clarify for everyone:
 
IceEdelweiss - Can you be more specific about what kind of defects you are referring to?  Such as "audible defects" and NOT "cosmetic defects"?
 
I think this is a worthwhile discussion, but it can take many different paths...
 
For instance, are we trying to find out if an amplifier has a defect, or how to find the defect?  In what way to troubleshoot?
 
Good topic.

 

[xnor]

High DC offset, too high current draw and possibly parts getting hot that shouldn't (oscillation), audible problems like clipping and high distortion (may be in one channel only), loud click when you turn on the amp ...

 

[286963]

Quote:

I don't have much to contribute in the way of information to this thread... but thought it would be nice to clarify for everyone:
 
IceEdelweiss - Can you be more specific about what kind of defects you are referring to?  Such as "audible defects" and NOT "cosmetic defects"?
 
I think this is a worthwhile discussion, but it can take many different paths...
 
For instance, are we trying to find out if an amplifier has a defect, or how to find the defect?  In what way to troubleshoot?
 
Good topic.

I refer to the audible defects. I don't care much of the cosmetic defects though..

 

[SeanDavid010]

Quote:

Hmm no replies?  my general stance has been if it sounds good then it IS GOOD.  

This is the correct answer (for me, anyways.)  If it sounds good, then run with it!

 

[kramer5150]

The other thing I do (once the warranty expires) is pop the cover off the amp and just give it a thorough visual inspection.  I'm just looking for the most blatant of manufacturing flaws... cold solder joints, partial hole fills, anything lose inside and not tied down.  P2P, high voltage tube amps make me nervous though.  I DON'T poke/mess around in these amps unless it absolutely needs it.  I steer clear of the bigger power caps and resistors.  But even then, once I'm in there I'll give each solder joint a thorough visual inspect.  I want all solid core solder points to be fully engaged with the solder... no partial or half-flows.