"Thup" when turning on amp

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Hammerhead

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Not sure if this is normal, but I notice a 'thup' (soft pop) when turning on my amp. The order in which I power up is: Preamp, then amp, power down is amp first, wait 10 seconds, then preamp.

It's been there for a while, just never thought to ask.

Should I be worried?
 
Lot's of things could be going on with your amp and or pre, caps go bad, protection circuits age, then some nasty, bad electrons run amuck. As I'm sure you probably know, you do not what any DC current heading out of your amp. Are you handy with test equipment ? I know some very good techs all over the country, just LMK if you want some help.

btw, I posted on your system about your speaker placement as well, happy tunes to you!! Craig
 
Lot's of things could be going on with your amp and or pre, caps go bad, protection circuits age, then some nasty, bad electrons run amuck. As I'm sure you probably know, you do not what any DC current heading out of your amp. Are you handy with test equipment ? I know some very good techs all over the country, just LMK if you want some help.

btw, I posted on your system about your speaker placement as well, happy tunes to you!! Craig
Thanks for that - I replied.

Actually, I didn't know about the DC thing. Have you ever heard of Bryston amps doing this sort of thing? Lucky I still have 3 years left on the warranty. Maybe I'll send it back after testing for DC to see what's happening. The sound really is not loud enough to do any damage to the speakers... yet. I didn't think of this, but maybe I'll shoot the Bryston folks an email to see what they say.

Thanks!

ETA: Something else just hit me - there's a 'ground lift' switch at the back of this amp. Might it be worth trying that in a different position?
 
Hola. Many power amplifiers use a relay for protection. When you power the amp, there is a circuit time delay and then the protection circuit waits for steady voltage and test if there is a remain DC voltage at the amplifier speaker´s output. If there is DC present, the trigger circuit does not act. It acts when everything is OK, then the relay acts, connecting the amplifier to the speakers. Your Bryston Power Amp does not have this kind of protection, because Bryston believe that the relay contacts might compromise the quality of the signal, so, the speakers are connected without this kind of protection. The thump that you are hearing is a transient due to the charging of the capacitors of the power supply. Bryston is built with double power supplies, one for each channel, and the only thing that have in common is the Mains AC power cord.

That thump is normal and does not cause any damage to the speakers. If you pay attention, the woofers are the ones that make this odd noise. The panels remains silent.
Happy listening!
 
Best sequence I believe, Power up / amp first. Power down / amp last.

This sequence ensures that the pre is out of the "circuit" during these operations.

FWIW, my amp has a small "thump" type sound when it is powered up if the pre is activated before hand.
 
Different manufactures apparently have there own procedures for powering on and off.

Audio Research recommends for ON preamp first muted then amps and for OFF mute preamp with volume at zero turn off amps them preamp.

You might want to check with Krell and Bryson to see what they recommend.
 

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