GK MB150 buzz

[wriggers]

Hi all

I'm new to the site and new to bass playing. I have a Gallien Kruger mb150 combo which has developed a buzz at medium to high volumes, buzzier on some notes more than others. The buzz all but disappears if preesure is applied to the side panel. I thought perhaps that there was a loose screw or two causing the panel to vibrate but they were all tight, apart from one at the top right which has a stripped thread presumably from a previous owner. With all the screws out the panel refuses to come off. Are they glued on/sealed in some way? Is there a component attached to this panel (right hand side as you look at the front of the amp) which may be loose. Does anyone have any ideas, I would be grateful for any responses?

Thanks in anticipation

Paul

[wriggers]

hi again

oops, I meant left hand side

[ThomBassmonkey]

Does the buzz get louder as you turn up the amp? Is it present if a bass isn't plugged in? Is it there if your bass is plugged in but you're not making any noise?

I'd give Polar Audio a call, they'll know best. [url="http://www.polaraudio.co.uk/"]http://www.polaraudio.co.uk/[/url] the phone number's at the bottom.

[icastle]

Try unscrewing the two screws that hold the top handle in place - looking at pics of the combo and the stand alone amp head I suspect that those two screws may go through the combo casing and into the amp chassis.

[wriggers]

[quote name='ThomBassmonkey' post='1181111' date='Mar 29 2011, 05:09 PM']Does the buzz get louder as you turn up the amp? Is it present if a bass isn't plugged in? Is it there if your bass is plugged in but you're not making any noise?

I'd give Polar Audio a call, they'll know best. [url="http://www.polaraudio.co.uk/"]http://www.polaraudio.co.uk/[/url] the phone number's at the bottom.[/quote]

There is normal amp noise but this is more like a rattle when playing at med to high volume as though something is or has worked loose.

[wriggers]

[quote name='icastle' post='1181118' date='Mar 29 2011, 05:12 PM']Try unscrewing the two screws that hold the top handle in place - looking at pics of the combo and the stand alone amp head I suspect that those two screws may go through the combo casing and into the amp chassis.[/quote]


I'll try that tomorrow, but it seems to me that there is something loose which is making the buzz against the side panel. Thanks for quick response.

[wriggers]

[quote name='wriggers' post='1181688' date='Mar 29 2011, 10:40 PM']There is normal amp noise but this is more like a rattle when playing at med to high volume as though something is or has worked loose. Thanks for quick response.[/quote]

[icastle]

If touching the side panel stops the vibration and there's nothing obviously loose externally then I'd be inclined to slide the amp chassis out just a little and try again (keeping you fingers out of the amp of course!).

I had a similar issue on a combo many years ago and ended up fixing it by pushing a scrap of foam between the amp chassis and the casing before screwing it back together.

It's all a bit hit and miss I'm afraid as it's mechanical instead of electronic noise.

[Mr Bassman]

I had an MB150 that buzzed

it was the speaker wire touching the cabinet.

I put an extra twist in it and it was fine.

hope this helps