Bass Stack Noise and Buzzing

[PhoenixBass1]

Hi everyone,

I have a ashdown bass stack, that this morning (when I was due to record) decided to start making a lot of buzzing and feedback noises. I fiddled around for quite a while trying to figure out what the problem is. I think i've gotten it down to being either the head or the speaker but would really appreciate some help if anyone else has had a similar problem.

More info
To narrow it down i've moved far and close to the stack and there has been no change. I've tried a load of different input cables and still the same. Unfortunately I can't test the head separately as I don't have another cab, so it's probably one of these or the cable between them which I also don't have a spare for. Any help would be really nice.

Cheers in advance,
Phoniex

[Ou7shined]

[quote name='PhoenixBass1' post='903277' date='Jul 23 2010, 03:21 PM']...I fiddled around for quite a while trying to figure out what the problem is. I think i've gotten it down to being either the head or the speaker.....[/quote]

So it's not the wood then, phew.

Seriously though we'll need more details. Model , age, what causes the symptoms (playing or just switching it on) etc.. If it's definitly the amp and not a dodgy cable or something, my gut instinct is the valve (if it has a valve front end) is shot.

[escholl]

I'm guessing from your sig the head in question is a MAG 300R? So it won't be a valve then, as this head is all solid state. I can help you narrow it down further and say, if it's just a constant buzzing, it's not the speaker either.

It sounds to me like there a broken ground somewhere. Does the amp make these noises even when there is no bass attached? Does turning up and down the preamp level affect the buzzing, and if not does turning the master volume up and down change it at all?

[PhoenixBass1]

[quote name='escholl' post='903483' date='Jul 23 2010, 06:54 PM']I'm guessing from your sig the head in question is a MAG 300R? So it won't be a valve then, as this head is all solid state. I can help you narrow it down further and say, if it's just a constant buzzing, it's not the speaker either.

It sounds to me like there a broken ground somewhere. Does the amp make these noises even when there is no bass attached? Does turning up and down the preamp level affect the buzzing, and if not does turning the master volume up and down change it at all?[/quote]


Yeh it is the MAG 300R. And ok thanks, so that means it's the amp head.

The noises are there when there's no bass attached. The preamp varies the buzzing a little and the master volume significantly increases the buzzing when turned up. Any help? Should i contact Ashdown then?

Thanks for your help

[escholl]

[quote name='PhoenixBass1' post='906801' date='Jul 27 2010, 10:51 AM']Yeh it is the MAG 300R. And ok thanks, so that means it's the amp head.

The noises are there when there's no bass attached. The preamp varies the buzzing a little and the master volume significantly increases the buzzing when turned up. Any help? Should i contact Ashdown then?

Thanks for your help[/quote]

Yes, if the preamp varies the buzzing level a bit, and it happens even with no bass attached, then you can be almost entirely sure there is something wrong with the preamp. The good news is it sounds actually like it would be a simple repair, most likely a dry joint somewhere although it could be a failed component. Either way, an easy fix for any competent tech. Yes, I would definitely contact Ashdown, give them a ring if you can, their customer support is well known for being very good so hopefully they will be able to help you.

[martinbass7750]

[quote name='escholl' post='907258' date='Jul 27 2010, 04:16 PM']Yes, if the preamp varies the buzzing level a bit, and it happens even with no bass attached, then you can be almost entirely sure there is something wrong with the preamp. The good news is it sounds actually like it would be a simple repair, most likely a dry joint somewhere although it could be a failed component. Either way, an easy fix for any competent tech. Yes, I would definitely contact Ashdown, give them a ring if you can, their customer support is well known for being very good so hopefully they will be able to help you. [/quote]


is it a detachable mains lead? it could be a bad earth connection so if it's detachable try a different lead, or if not open the mains plug and check all the leads are connected and screwed up tight.

[PhoenixBass1]

[quote name='martinbass7750' post='907498' date='Jul 27 2010, 07:43 PM']is it a detachable mains lead? it could be a bad earth connection so if it's detachable try a different lead, or if not open the mains plug and check all the leads are connected and screwed up tight.[/quote]

Thanks but i've already tried it and the noise was still there, I also tried different mains plugs so i'm fairly sure it's not that

[PhoenixBass1]

Thanks for your help guys. I took my head to the Ashdown repair centre yesterday, which happened to be just up the road from me. It turned out it was a grounding problem and is all working fine now