Markbass sd800 noise problem

[julesb]

Hi everyone,

 

Before I think about taking this to a repairer does anyone have any ideas what could be causing this sound? There's a pretty much constant woosh/hiss which you can't hear when playing but sometimes it makes the sound in the attached file which then goes away for a while and then starts again randomly. The leads are all good and I've checked for obvious cold solder points. The amp works perfectly apart from this but I fear it will break when I need it most. Interestingly it doesn't make this sound through the built in DI which is perfectly quiet.

 

Any ideas appreciated. The amp is quite old now so it may be a case of it becoming a paperweight if it's expensive to fix.

 

Thanks in advance.

 

p.s. The fan never seems to come on. I replaced it and it's still the same but it doesn't seem to get hot.

[yorks5stringer]

Not qualified to comment but doubtless you've followed the threads regarding the only Markbass Service Centre that (theoretically) can repair it?

[julesb]

Yeah, I'm actually in Germany but it's the same thing here. One service centre. Unless a board needs replacement it might be doable by a regular repair person. (he says hoping...)

[BassBunny]

12 hours ago, julesb said:

Yeah, I'm actually in Germany but it's the same thing here. One service centre. Unless a board needs replacement it might be doable by a regular repair person. (he says hoping...)

The main issue is that MarkBass will not supply circuit diagrams and so repairing at component level becomes virtually impossible unless something is completely "fried" and obvious.

When my SA450 developed a problem the repair cost with the authorised repairers was more than it was worth.

[julesb]

Ok fair enough. Looks like new amp time. This is the second issue I've had with Markbass so I'll try my luck elsewhere this time. Clearly people have great experiences with MB so I know they're not all bad. I'll take it in a some point to the local electronics guy and you never know...

 

Cheers!

[BassBunny]

Have you tried the "effects loop" trick?

Shove a jack plug in and out of the effects send and return jack's. These are prone to oxidizing if never used and can cause issues like yours. It's worth a shot. 

A local electronics guy is also worth it as long as you don't have high expectations and they aren't that expensive.

[lownote]

As I have reported elsewhere, my MB LM2 developed a strange occasional nasty sound after I dropped it. Knowing I would get nowhere with Real the official repairers I took it to a local guy. Bear in mind this is Norfolk.  He eyed the amp then whacked it hard with a length of 2 by 4.  For non carpenters that's a size of timber, 2 inch by 4 inch and whatever long. The amp worked fine after that.

[julesb]

For what its worth, my final attempt before taking it in was to replace the neutrik speakon connectors which I had my eye on from the beginning. Voila, the amp is back and sounding great.

[BassBunny]

Just now, julesb said:

For what its worth, my final attempt before taking it in was to replace the neutrik speakon connectors which I had my eye on from the beginning. Voila, the amp is back and sounding great.

Result.