The Dude Posted March 23, 2016 Author Share Posted March 23, 2016 1. Spark or brief electric arc caused by main power on/off switch of power amplifier. Each time the amplifier is switch on or off, a spark jumps across the gap. It can get pretty loud, especially if you are not expecting it. 2. Inrush current surges where there is an instantaneous input current draw by the transformer when the amplifier is first turned on. When an E-core transformer is first energized, the transient current can increase up to 15 times larger than the rated transformer running current. Toroid transformers can have up to 60 times inrush to running current. 3. DC offset at the output of your power amplifier, which is typically not nearly as loud of a thump (much more mild) as the spark/electric arc thump. If you have DC Offset voltage issues, the addition of an output relay with a delay will eliminate the thump sound on power up. However, this only removes the “sound” and does not solve any potential amp issues if the DC Offset is actually too high at the output. If I had to guess 1 and 2 could be design flaws and 3 would be an actual issue. Reason I state this, After talking to Bryston in Ontario, I was directed to Vermont. The fellow in Ontario made it sound like that as long as the amp was under warranty ( which one of them is). That It could be sent in to be updated, which would limit the thump/pop. However when discussing this with the fellow in Vermont. He states that do to designs of the older units ( leading up to the early 2000's) that this is normal and no modification or update is covered under warranty. I basically told him that this is unacceptable. That if there was a design change do to a known problem then there should be a TSB and any product under warranty should be updated. He couldn't guarantee anything, but he did agree to take a look at it and consult with Bryston if the update/modification would be covered under warranty. So I am waiting on the appropriate packaging material, which I had to pay for. I will I am not as much excited about their service I started out to be. We will see what happens. Do I expect them to fix it, not if there is no problem I don't. But if there is known solution to a know problem, I think they should. 1 Quote Link to comment Share on other sites More sharing options...
robertg Posted December 19, 2017 Share Posted December 19, 2017 Did you ever solve your issue? I am using a 2BLP to power my mids and it makes a pretty loud noise when I turn it off. Bryston said I could sent it back for repair, but they couldn't guarantee that the noise would be completely gone. My amps are about 30 years old, so no warranty. Quote Link to comment Share on other sites More sharing options...
The Dude Posted December 20, 2017 Author Share Posted December 20, 2017 3 hours ago, robertg said: Did you ever solve your issue? I am using a 2BLP to power my mids and it makes a pretty loud noise when I turn it off. Bryston said I could sent it back for repair, but they couldn't guarantee that the noise would be completely gone. My amps are about 30 years old, so no warranty. No, unfortunately I could not, so I sold the amps. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted December 20, 2017 Share Posted December 20, 2017 Did you ever try turning just the amp on and off and see if you got the thump? Using the triggers powers things on and off too closely for some equipment. I always start with the sources, preamp, then processor, then amps once the other units are stable. To turn off I start with the amps.........then wait several seconds for the decay. When no sound can then get to the speakers I power the other components down in reverse order........processor, preamp and sources. I never use triggers. Quote Link to comment Share on other sites More sharing options...
The Dude Posted December 20, 2017 Author Share Posted December 20, 2017 1 hour ago, mark1101 said: Did you ever try turning just the amp on and off and see if you got the thump? Using the triggers powers things on and off too closely for some equipment. I always start with the sources, preamp, then processor, then amps once the other units are stable. To turn off I start with the amps.........then wait several seconds for the decay. When no sound can then get to the speakers I power the other components down in reverse order........processor, preamp and sources. I never use triggers. One of them would still make a thump when using that sequence, the other not so much. I use Crown D45 and have used McIntosh MC2505 with no thump using triggers, maybe a slight pop, but no thump. So I will stick with what I know works. This way my wife and kids can enjoy the system when I am not around. Quote Link to comment Share on other sites More sharing options...
robertg Posted December 20, 2017 Share Posted December 20, 2017 20 hours ago, The Dude said: No, unfortunately I could not, so I sold the amps. Did you sell them without trying to get them modified by Bryston? Quote Link to comment Share on other sites More sharing options...
The Dude Posted December 20, 2017 Author Share Posted December 20, 2017 8 minutes ago, robertg said: Did you sell them without trying to get them modified by Bryston? Yes. There wasn't a guarantee it would fix the issue nor did I want to hassle with it, not for the money. Quote Link to comment Share on other sites More sharing options...
robertg Posted December 21, 2017 Share Posted December 21, 2017 Thanks for the help, I'm thinking the same. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.