[NIGELJAMES]

Have you tried turning off the tube buffer and see how it affects the hiss that you hear?   At high volumes with no input signal, I hear noise until I turn off my inline tube buffer.  I do not hear noise at normal listening levels with the tube buffer in operation.

Yes I have tried that but no significant difference. I recently replaced stock tube with a new Full Music 12AX7 and although SQ seems to have significantly improved the hiss has not so I don't think its the tube. I fully suspect its the power supply. My HE-6's sound excellent, I listen to rock and metal so the hiss does not bother me too much, but its a lot worse with the LCD-2's and makes them unlistenable. Nice to hear other people are using headphones with out any hiss problems.

[NIGELJAMES]

While your amp is turned off, twist the volume control back and forth several times quicklt. The hiss I had is completely gone when the volume was adjusted. Member parkfly here said it was caused by oxidation of the contacts, or something like that.

Thanks for the tip I will try that later.

[NIGELJAMES]

Switching to battery power helps cut down on the noise floor hissing. My Sensation is very quiet now.

Good to hear that, its the only downside at the moment.
I expect moving from the cheapest power supply to batteries will yield a big difference in SQ and hopefully noise levels. 

[HiFlight]

I forgot to add that I am using the battery power supply with my 2.2 and hear no hiss or hum with any of my balanced phones. 

[Jason T]

if you removed the tube and the try it and have no hiss then its the tube, make sure the buffer switch is off and the power is off before attempting it.

[NIGELJAMES]

if you removed the tube and the try it and have no hiss then its the tube, make sure the buffer switch is off and the power is off before attempting it.

I tried what you said Jason and there is still hiss, however it is significantly reduced and does not change with volume unlike when used normally. Also the hiss does not seem to differ much if at all when the buffer is disabled with tube still in place.
I am waiting for the battery power supply to be sent so hopefully that will help.

[Jason T]

the battery supply should eliminate the hiss.

[abernardi]

  Reviving an old topic fellow Virtuous listeners.  I just pressed my battery powered M901 w/Dodd buffer into service with my LCD-2 headphones using a balanced cable off the speaker terminals.  I am also getting a big big hiss.  The sound quality is excellent, the best I've heard with these headphones, but the hiss is a deal breaker, I'm sad to say.  As with NIGELJAMES, the hiss is there with and without the buffer engaged and is independent of volume. 
  I had this amp driving some VERY sensitive speakers with a folded ribbon AMT and I didn't hear ANY hiss.  So I'm not sure it's a matter of sensitivity.  I think the LCD-2 is a 50 or 60 ohm load,  could that have something to do with it?  And the "leaf rustle" is very loud, but that's a known entity and only happens when I adjust the volume.  BTW, there is an abundance of power, I only have the volume control at about the 7 o'clock position, any louder would make my ears bleed.  I'd love to be able to make this fine amp work for me, any ideas?

[virtue]

Adam,

You're probably right.  I wonder if adding some resistance will help.  Next time we meet up I'll give you some things to try.

Seth