amp rumble (tech help please)fixed

[maximus1]

my rm100 has a rolling thunder rumble type sound pouring through the speakers it worstens to a loud pop when i turn up the pre amp volume. sounds like someone blowing into a mic kinda. tried all types of tube swaps pre, and power no luck there. does it without the guitar plugged into it even. i took it to a tech and no one so far can figure it out. please help if you can. the hotter the tubes get the badder the problem gets

 

[maximus1]

sweet thanks for your help :x

 

[rjmmusic]

Did you replace all of the tubes in the amp? Sure sounds like a tube problem to me.

 

[kc2eeb]

I would do a very careful check of any resistor carrying any significant current such as plate resistors, dropping resistors, etc. Also check coupling caps, etc. Start without any modules installed. Then do a tap test. Take something NON-conductive (like a wooden dowel) and start tapping the components. I've seen resistors that looked perfect and actually were separated where the lead meets the resistor body. Give everything a GENTLE tap or push and see what happens. The reason I'd suspect resistors is the the problem worsens as the amp heats up. Pat L.

 

[maximus1]

thanks i'll try that, all you have to do is tap the top of the amp and it starts a static rumble throught the speakers and tapping on the power tubes can either get rid of it or bring on more so i know it has to be some kind of power flow issue. doesn't matter what kind of tubes i use , as soon as the tubes get some heat in them the static rumble starts coming in and out of the speakers.

 

[bruce egnater]

Which knobs affect the noise and which don't? Is it on all the modules? Does it stop when you turn down the module gain knobs? Does it stop when you turn down the main master?

egnater

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[maximus1]

i'm glad you re here. the amp makes a static rumble through the speakers just by powering it on and letting the tubes warm up. turning up knobs on the modules doesn't do anything nor doeas the master volume knob. its the amp itself. i've changed everypower tube and pre amp tube and it hasn't helped. if you tap on the top of the amp on the case it will rumble. i could literally play drums on the top of the amp while it is on. i have the blackface module and 2 diferent ultras. it doesn't matter what module i have it on it'll rumble anyway. i won't even plug the guitar into it anymore because playing this amp isn't an option anymore. i've also changed all the cables and it doesn't help. if you tap on the power tube next to the big transformer it is alot louder of a thud than the rest but it does that no matter what tube i change it with. please help i can't figure it out an the tech i took it can't either. its no longer under warranty and i have gigs booked with no other amp for back up and no money to get a new amp :x

 

[bruce egnater]

It obviously has some sort of loose connection inside. Sounds like you've done all you can do by changing tubes. Since it's not a tube problem, it will need to be repaired by a repair tech. I wouldn't think it would be that difficult to figure out. Schematics are available if needed. I don't think you are in need of a "new" amp, just a good repair person.


Egnater

 

[maximus1]

thank you for helping , much appreciated 8)

 

[maximus1]

back in action after being reduced to ss amps for practice and gigging. it feels so good to play a tube amp again, especially a randall :lol: be weary of the wires coming out of your pt 100 in an rm100 apparently mine got into a rubbing match with the chassis and it turned into a static sounding fuse blowing machine.