[Smalltalk80]

I received my ONE.2 classic with the standard PSU and I'm thrilled with the craftsmanship and the sound quality.
But there is one little vexing issue. Is it supposed to hiss like a normal amp when turned on? There is this slight hissing like from my old amp or any normal analog amp. I thought the T-amps would have almost completely noise free backgrounds. It's there when the pot is turned all the way down and gradually increases when it is set to maximum. I use CAT5 for speaker cables so even though the cables run through lots of electrical wires it can't be from than.
Granted, I have very sensitive speakers (Fostex FE126 units in BIBS), but still...?

[ismarketing]

My one classic does the same thing with the 13ow PSU.  I found that placement/dressing of the power cord to the amp makes a difference - move it one way, silence.  The other, his.  Adding a ferrite bead it the end of the power cord where it enters the amp also helped to lower the hiss.

FWIW - my 2.2 has the same issue, though to a much lesser degree.  I used to fret about it, now I just enjoy the amp.

Good luck.

[dvenardos]

That slight hiss is normal for switching amps (tripath). It is not distortion like with a class a/b amp. With lower sensitivity speakers you can't hear it unless you stick you ear right up to the speaker and you shouldn't hear it at all when music is playing. How close do you need to be to hear it?

[Mama Virtue]

SmallTalk, the 65W produces more noise than the 130W. Would recommend the 80W as many customers have that, but they are out of stock, and possibly indefinitely. The 130W is near silent. It IS possible that a ferrite inside the amp came loose in shipping and is creating more noise....

If you really want near total silence I would recommend investing in the Dodd Audio 5Ah Battery supply for $149. You can leave it plugged into the charger 24/7, and many customers have found it to be a great addition to their system.

[Smalltalk80]

It seems I'm not the first one to post about this.
http://www.audiocircle.com/index.php?topic=78595.msg746064#msg746064
Looks like it is the PSU. I was contemplating upgrading to battery supply at some point I guess...
Just good to know there isn´t something wrong. Now it just the freaking supernova of a diode on the front. 

I can make out the hiss in a silent room at about two metres distance, at normal listening volume. Is that normal?

SmallTalk, the 65W produces more noise than the 130W. Would recommend the 80W as many customers have that, but they are out of stock, and possibly indefinitely. The 130W is near silent. It IS possible that a ferrite inside the amp came loose in shipping and is creating more noise....

If you really want near total silence I would recommend investing in the Dodd Audio 5Ah Battery supply for $149. You can leave it plugged into the charger 24/7, and many customers have found it to be a great addition to their system.

Is the ferite coming lose a common thing and how exactly would it sound and how loud? My noise is pretty much like the guy in the thread I linked to explains it.

[dvenardos]

Wow! With batteries and 86db speakers I have to stick my ear right up to the tweeter to hear any hissing. It was about the same with the 90 watt PSU. I have the 65 watt in the garage I will have to hook that up and see what it sounds like.

I can make out the hiss in a silent room at about two metres distance, at normal listening volume. Is that normal?

[Smalltalk80]

Wow! With batteries and 86db speakers I have to stick my ear right up to the tweeter to hear any hissing. It was about the same with the 90 watt PSU. I have the 65 watt in the garage I will have to hook that up and see what it sounds like.

Well mine is 93db...

[Mama Virtue]

Is the ferite coming lose a common thing and how exactly would it sound and how loud? My noise is pretty much like the guy in the thread I linked to explains it.

The ferrite coming loose is not common, but anything is possible from shipping.

[envisionelec]

Also, the front end of the amplifier is analog. As such, there is always a little noise present. With highly efficient speakers in a quiet room it is indeed possible to hear this noise.

Regards,
Aaron