• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Need assistance with Amp/Cab vibrations

JDLowEnd

JDLowEnd

Dec 19, 2010
850
1,127
Norwich, CT
#1
Alright so I got a new amp and cab setup. The amp is a Fender Bassman 300 and the cab is a custom built cab from a builder in MA. It is an oversized 15'' cab that was designed specifically for this head. I got this new rig yesterday and I used it at practice today. The sound is awesome and really incredible. I had an issue, however, with vibrations! This head is super heavy and the vibrations from the cab was causing the amp to move around on top of the cab. Now I think I remember the specs putting the head at 75lbs, and the vibrations were still causing it to move around on top of the cab. I wanted some ideas on how to remedy this. I am thinking to purchase the metal circles like on the ampeg cabs that the rubber feet sit in, but that's my only idea so far. The amp does have rubber feet on the bottom as it should. Any ideas would be helpful!
 

Attachments

  • Fender and Kneel.jpg
    Fender and Kneel.jpg
    364.7 KB · Views: 125
#2
JDLowEnd said:
Alright so I got a new amp and cab setup. The amp is a Fender Bassman 300 and the cab is a custom built cab from a builder in MA. It is an oversized 15'' cab that was designed specifically for this head. I got this new rig yesterday and I used it at practice today. The sound is awesome and really incredible. I had an issue, however, with vibrations! This head is super heavy and the vibrations from the cab was causing the amp to move around on top of the cab. Now I think I remember the specs putting the head at 75lbs, and the vibrations were still causing it to move around on top of the cab. I wanted some ideas on how to remedy this. I am thinking to purchase the metal circles like on the ampeg cabs that the rubber feet sit in, but that's my only idea so far. The amp does have rubber feet on the bottom as it should. Any ideas would be helpful!
Click to expand...

Get a foam mat and put it on top of the cab. Basically, you want a piece of a yoga mat. I know my local dollar store sells small sheets of the stuff, I would start there.
 
  • Like
Reactions: Pbassmanca
#4
JDLowEnd said:
I think that should work, I will take a look and see if I can find one. You mentioned they sell it by the sheet? Is there a name of the product?
Click to expand...

I think it was just a generic "foam mat" or something. It was probably a placemat. I just noticed it browsing through and thought "that would be perfect for keeping your amp in place." This subject has come up a few times on TB.

Yes, my real life is actually that boring...
 
  • Like
Reactions: Bass Man Dan
#10
I had a Sunn model T. Used it with Sunn’s 1-15 reflex scoop for years.
I always put a pillow between the head and cabinet.

My first good amp (1972)was a Bassman 50. I also used a pillow because the knowledge on the street was that the vibrations were not god for the tubes.
Guys we’re doing the same with Acoustic 371 amps too.
 
#12
JDLowEnd said:
Alright so I got a new amp and cab setup. The amp is a Fender Bassman 300 and the cab is a custom built cab from a builder in MA. It is an oversized 15'' cab that was designed specifically for this head. I got this new rig yesterday and I used it at practice today. The sound is awesome and really incredible. I had an issue, however, with vibrations! This head is super heavy and the vibrations from the cab was causing the amp to move around on top of the cab. Now I think I remember the specs putting the head at 75lbs, and the vibrations were still causing it to move around on top of the cab. I wanted some ideas on how to remedy this. I am thinking to purchase the metal circles like on the ampeg cabs that the rubber feet sit in, but that's my only idea so far. The amp does have rubber feet on the bottom as it should. Any ideas would be helpful!
Click to expand...

IMHO...put the amp on a seperate stand. My Greenboy Dually vibrates quite a bit also, and if the power tubes are a bit loose the vibrations can cause all sorts of problems. Recently retubed an amp and it worked fine for over two weeks until I put it on the Dually. With the vibrations the amp blew a fuse. Replaced the fuse and the amp worked fine again...until I put it on the Dually. This time there was a bright flash of light and an extremely loud noise that sounded like a bomb going off. Retensioned the tube sockets and the amp works fine, but ongoing vibrations would likely cause the contacts in the tube sockets to loosen up over time.

I plan to get an aluminum camp table to put my amp on as the Dually is pretty tall. As your speaker is relatively short, maybe you could use something like a Quiklok WS540 to straddle the speaker.
WS540_m.jpg
 
#13
All suggestions that do not include adding bracing to the cab are just addressing the symptoms.

To fix the root cause of the problem requires bracing the cab.

Edit: sorry if I sound like a pompous know-it-all here. It affects all of us. Last week I was testing my prototype vertical 4x10, and my 9-pound Ashdown Rootmaster was traveling across the top every time I hit an A. Imagine what my 2-pound GK MB200 would do! This morning I glued in what are hopefully the last braces needed, but only more testing will confirm. Nobody is immune!
 
Last edited:
  • Like
Reactions: BassikBrad, BrBss, Loring and 4 others
#14
ctmullins said:
All suggestions that do not include adding bracing to the cab are just addressing the symptoms.

To fix the root cause of the problem requires bracing the cab.
Click to expand...

Can't disagree with this. I added bracing from side side, and top to top to rear to some old crappy cabinets I have, and it made a huge difference in the sound and greatly reduce vibrations.
 
  • Like
Reactions: BrBss, JKos, Loring and 3 others
#15
Wasnex said:
Can't disagree with this. I added bracing from side side, and top to top to rear to some old crappy cabinets I have, and it made a huge difference in the sound and greatly reduce vibrations.
Click to expand...
Vibrations can reduce the amount of energy that emanates from the speaker outward.

Maybe @agedhorse might chime in and explain the physics.
 
  • Like
Reactions: Pbassmanca
#16
JDLowEnd said:
Alright so I got a new amp and cab setup. The amp is a Fender Bassman 300 and the cab is a custom built cab from a builder in MA. It is an oversized 15'' cab that was designed specifically for this head. I got this new rig yesterday and I used it at practice today. The sound is awesome and really incredible. I had an issue, however, with vibrations! This head is super heavy and the vibrations from the cab was causing the amp to move around on top of the cab. Now I think I remember the specs putting the head at 75lbs, and the vibrations were still causing it to move around on top of the cab. I wanted some ideas on how to remedy this. I am thinking to purchase the metal circles like on the ampeg cabs that the rubber feet sit in, but that's my only idea so far. The amp does have rubber feet on the bottom as it should. Any ideas would be helpful!
Click to expand...
How much does the speaker cab weigh?

Have you peaked inside?
 
  • Like
Reactions: Pbassmanca
#17
Stumbo said:
Vibrations can reduce the amount of energy that emanates from the speaker outward.

Maybe @agedhorse might chime in and explain the physics.
Click to expand...

When the cabinet panels move, some energy is dissipated but in reality it may not be much. I prefer a pretty stiff cabinet myself, but some looseness can contribute to tone IF it's done tastefully and with purpose. This gets into "secret sauce" areas where control rather than total elimination is the goal.
 
  • Like
Reactions: smeet, Al Kraft, Munjibunga and 1 other person

Latest posts

Top Bottom
Back