Neve 1073 shot noise?

I'm making tests on my 1073 clone. Everything seems fine except I can hear the sort of noise like a popcorn type. Is this transistor shot noise or what?

I wonder if the originals and other clones have this type of noise? Can anybody with the 1073 at hand check this? The noise is heard at the maximum gain setting with EQ bypassed.
Here's the link to the sample
(it's normalized, so beware - it may be loud).

What is a general approach to this type of problem? Where do I start and which tools to use (given the random character of the noise)?

i had exact same noise after travelling with mine... i had it at after half way trough the gain...
i rewired the grounding, its all great now.

I did not listen.

Popcorn, not hiss?

Popcorn Noise was a problem into the 1960s, pretty-much cured by cleaner Silicon.

Otherwise, popcorn is likely to be a bad connection. Plugs are prone to it. So is solder globbed on a wire but not really wetting it.