Noise on 7B2

[AVfile]

I’ve seen a lot of nice stories on Facebook lately of people getting their older 3B and 4B amps tuned up by the factory. My 7BSST2 are only 9 years old but there has always been some buzzing noise audible if you stand close to the tweeter/mid. Knowing that big amps can do this it does not really bother me, but it is different than the usual hiss (white noise). So I decided to measure the output at the speaker terminals.

Amp 1:
0.4 mV AVG
Min -2.5 mV
Max +2.5 mV

Amp 2:
-7.4 mV AVG
Min -11.5 mV
Max -3.6 mV

I don’t think this is anywhere near the specified -117 dB SNR which should be less than 0.1 mV by my calculations. Also looks like Amp 2 has a significant DC offset. What have others found?

Can Bryston fix this?