Noise on 7B2
 

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?

Sure they can. Send in for warranty. Most likely a bad capacitor(s). I had my 14B SST with one channel bad. They replaced a bunch of things and got it back to factory specs.

OK thanks. I called Bryston and was told to email Mike because he is working from home so now I’m just waiting for his reply.

Where Bryston is located in Ontario, we just came out of full lock down due to COVID. Stereo stuff is non essential. So may be some long delays getting things fixed.

Non-essential? How dare they!

Lol! Ontario even shut down all ski resorts. Only place in North America.

Noise on 7B2
 

Mike @ Bryston gave me a reply and authorized return after second email. Amps are on their way to Peterborough tomorrow. Sending the preamp as well for checkup. I’m putting a lot of faith in FedEx! I would drive them there myself but it’s not a safe drive from Ottawa in the winter.

Never had anything but excellent service with any of my Bryston gear (though always goes to VT for us down here).
Hoping the weather is nice for the Tulip Festival. We're booked into the Chateau Laurier for a few days. Always enjoy the festival and the Byward Market.

Noise on 7B2
 

While the weather is looking good we got hit with a third wave of Covid and have only vaccinated 10% of the population. So the province is back into a 4 week lockdown and summer festivals are being canceled! You should cancel your booking unless you want to spend it in quarantine. Sucks for us too because we appreciate your tourism.

Got the amps back from Bryston. No fault found so they didn’t do anything! Mike must be fed up with me because I can’t get an answer out of him on the DC offset. I can live with a barely audible noise but the 7mV DC in one amp has me worried.

They did some updates on the preamp but it hasn’t fixed any of the glitches. The preamp actually makes more noise than the amps!