GK 200MB combo buzz help

[OHBandit]

I have an older GK 200MB combo that is buzzing at lower frequencies. I don't think it's the speaker. Had that repaired a couple years ago. If I take either of the side panels off and play with them off it goes away. I have tried pushing around on the grill and other areas while playing and it has no effect on the buzz. Any ideas?

 

[Joe Louvar]

I have an older GK 200MB combo that is buzzing at lower frequencies. I don't think it's the speaker. Had that repaired a couple years ago. If I take either of the side panels off and play with them off it goes away. I have tried pushing around on the grill and other areas while playing and it has no effect on the buzz. Any ideas?

Huh, side panels? Do you have pic's?

 

[OHBandit]

Here's a pic.

 

[OHBandit]

anybody?

 

[Joe Louvar]

Here's a pic.

Wow. It looks like the cab has been trashed from pulling it apart and probably all you can do is put it back together with added glue and clamps, wait 24 hours, unclamp and hope. Good luck

 

[Hello?]

Had a similar issue with a GK 250ML (git amp). Replaced all the seals - the original ones were ragged and felt oily.

 

[OHBandit]

Wow. It looks like the cab has been trashed from pulling it apart and probably all you can do is put it back together with added glue and clamps, wait 24 hours, unclamp and hope. Good luck

Why would taking the screws out of the side panel and removing it trash the cab? Worst case is it needs new seals.

 

[Bass is base]

I have an older GK 200MB combo that is buzzing at lower frequencies. I don't think it's the speaker. Had that repaired a couple years ago. If I take either of the side panels off and play with them off it goes away. I have tried pushing around on the grill and other areas while playing and it has no effect on the buzz. Any ideas?

I have owned a GK 200MB since 1986. I have also had issues with the cabinet buzzing at low frequencies. It took me years to solve the problem. There is a rubber cylinder that is held in place by a screw in the centre of the back panel. This rubber cylinder has an interference fit between the centre of the back of the speaker and the back of the cabinet. Over time the rubber shrinks and hardens and losses its ability to keep the back of the cabinet from resonating. I made an x shaped brace from brass rectangular bar that I soldered together. I fix the brace to the back of the cabinet using the same hole that was used to hold the rubber cylinder in place. I have drilled and tapped four holes into the brace on a 3 1/8" diameter bolt circle. I screwed four vibration damping screws into the holes that I bought on eBay. I unscrew these dampers till they press against the back of the speaker magnet. This makes the tension micro adjustable so you can adjust the tension. I have also upgraded the speaker to an Eminence 3012HO which has a sensitivity of 100.5db. Many times more efficient than the horrible Pyle speakers that come stock and have foam surrounds that rot and disintegrate. Even with a speaker that has many times the volume of the original, my 200MB does not resonate. I was lucky to find an old 200MP powered monitor that I made the same modifications on. Together these two

put out enough power to be enough for a Blues Band that plays at medium volumes. The tone is amazing. I suspect that has something to do with the fact the cabinets are sealed rather than ported. I find my other bass rigs sound boomy in comparison.

 

[dylanjohnson]

I have owned a GK 200MB since 1986. I have also had issues with the cabinet buzzing at low frequencies. It took me years to solve the problem. There is a rubber cylinder that is held in place by a screw in the centre of the back panel. This rubber cylinder has an interference fit between the centre of the back of the speaker and the back of the cabinet. Over time the rubber shrinks and hardens and losses its ability to keep the back of the cabinet from resonating. I made an x shaped brace from brass rectangular bar that I soldered together. I fix the brace to the back of the cabinet using the same hole that was used to hold the rubber cylinder in place. I have drilled and tapped four holes into the brace on a 3 1/8" diameter bolt circle. I screwed four vibration damping screws into the holes that I bought on eBay. I unscrew these dampers till they press against the back of the speaker magnet. This makes the tension micro adjustable so you can adjust the tension. I have also upgraded the speaker to an Eminence 3012HO which has a sensitivity of 100.5db. Many times more efficient than the horrible Pyle speakers that come stock and have foam surrounds that rot and disintegrate. Even with a speaker that has many times the volume of the original, my 200MB does not resonate. I was lucky to find an old 200MP powered monitor that I made the same modifications on. Together these twoView attachment 2935298 put out enough power to be enough for a Blues Band that plays at medium volumes. The tone is amazing. I suspect that has something to do with the fact the cabinets are sealed rather than ported. I find my other bass rigs sound boomy in comparison.

@Bass is base Were you able to stop the vibration by dampening the back of the amp to know that the shrinking rubber cylinder was the problem?