Noisy Transformer

If I remember correctly, the dealer tried their best to help. They sent a second amp, and after realising the same issue with the second amp, they sent a power conditioner thinking it must be DC on mains. It turned out there was most likely something wrong with both amps... strange, but sh&* happens...

The diyAudio community also tried to help... and helped they did. To me, the noise/buzz recording sounded like a combination of mains hum, but there were a lot of other frequencies there as well... so, it still seems like amps were at fault.

Wayne chimed in on many occasions, and he is ready to look into both amps because... both amps are now back at the dealer... so he can get hold of them.

The customer got his money back.

Happy End
 
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All that really matters here is that Andy Cine has received a satisfactory outcome, a full refund.

These are my own thoughts for what they are worth...

Speculating is pointless, there are to many unknowns as to the whys and wherefores of what has happened.

It would have been good to have another new and identical amp tried at the same location, the outcome of which would have led to a couple of possible routes... either the original had a one off problem or conversely both do the same at that location. If the later then that would need a much more detailed analysis by a Pass Labs representative, firstly determining if the noise was excessive.

If it was then both amps would need trying at another location to prove beyond doubt that they are silent elsewhere.

Assuming they are then a check of the mains at the original location would need to be done with the amp powered and buzzing while looking for any obvious issues such a distortion, asymmetry etc of the incoming mains.

So we just don't know and can't really say any more as things stand.
Hi Mooly, I did try two new Pass Labs INT -25s, and both had unacceptably annoying buzzing, unlike my previous amps from Leema, Musical Fidelity, Denon, and Naim.
 
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That's fair enough and that would start to seem to point to something very unexpected on such a product.

Although it would be good to hear more of 'what happens next' I suspect we will not find out more details of what is happening and causing this and why.
 
However, even after reading that excellent article we still remain in the field of possibilities.
Since this is a technical problem, there must be a technical, or engineering explanation, don't you?
Otherwise it strangely becomes to seems a philosophical issue.

On the other hand there is nothing that can not fail of human genius and/or of human built technology.
 
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