Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Platefire on December 05, 2011, 11:33:00 pm

Title: Mesa Boogie Rocket 440 Standby Pops when switched off
Post by: Platefire on December 05, 2011, 11:33:00 pm

My Mesa Boogie works fine, its just when I turn stanby switch from standby to play--it gets a few short pops of static. Never had this before on my other amps so I don't know what to look for to correct it. Anybody had this before??? Platefire

Title: Re: Mesa Boogie Rocket 440 Standby Pops when switched off
Post by: TIMBO on December 05, 2011, 11:57:30 pm

Hi plate, I'm glad that you have posted this problem. I have had a lot of funny goings-ons with my TOS build and this is one of the things that i was experiencing, i was also getting a loud thump when turning the standby off and i would get another when turning the power off. I not sure this is the same as your problem. Thanks

Title: Re: Mesa Boogie Rocket 440 Standby Pops when switched off
Post by: Platefire on December 06, 2011, 08:56:31 am

Hello TIMBO, well in my case it must have something to do with when I switch the standby off and the full DC power is un-leashed to the amp. Something is not handeling it well. I guess first suspect would be a preamp tube/power tubes, #2 bad contact on tube socket, #3 arcing on a socket or wire/connection too close together, #4 Plate resistor with issues, #5 Filter cap going bad, #6 go fishing with a chop stick. I guess I was hoping someone would chime in and say "oh yeah" that's bla bla bla--but I should know by now this could be a lot of things. Think I've got JCM800 PCB battle riggors---face your fear Platefire. I think I've answered my own post.  :think1:

BTW--so this may apply in your case--but a loud thump sound is a different kind of sound than I'm getting. My first suspect is always tubes and socket contact--and I go from there. In a new build I always go back and go over everything because a mis-placed component/value could do that. Does the amp sound good in normal operation beside the standy noise? What does TOS stand for?       

Title: Re: Mesa Boogie Rocket 440 Standby Pops when switched off
Post by: Jack1962 on December 06, 2011, 09:57:07 am

check filter caps , do you have a schematic for this amp ? If so posting it might get you more and most likely better suggestions  :m8

Title: Re: Mesa Boogie Rocket 440 Standby Pops when switched off
Post by: phsyconoodler on December 06, 2011, 01:09:08 pm

change the switch. 9 times out of ten it's the switch itself.you can also solder a capacitor across the terminals of the switch to prevent pops.a .047uf/630v cap from one side to the other..Lots of solid state amps I work on have that capacitor to prevent pops.

Title: Re: Mesa Boogie Rocket 440 Standby Pops when switched off
Post by: RicharD on December 06, 2011, 04:07:14 pm

+1 to what Phsyco said.

Title: Re: Mesa Boogie Rocket 440 Standby Pops when switched off
Post by: Platefire on December 07, 2011, 12:46:32 am

Well that's a solid lead! I'll take it! Thanks, Platefire