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My Marshall MG50 DFX Has an awful buzzing sound that comes out of it after startup.

I had the amp working for a rehearsal, then later in the day I took it to the gig and when I turned it on, checking both channels and all knobs down, the amp made a very loud buzzing sound. The Guitar signal stil goes through, but it's hard to hear over the buzz. I checked out that pre-amp test, and the guitar signal indeed came out of the headphone jack with the speaker unplugged. Also, when the speaker is plugged in, signal still comes out of the headphone jack, but the loud buzz and guitar signal come out of the amp speaker. The only thing I did between the rehearsal and the gig was unplug the speaker cable so that when I started up the amp it wouldn't make that horrible squeeling sound. When I plugged the speaker back in, the buzz started. Ideas?

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I would check C22 and C24 the main smoothing capacitors. They can fall out at worst or just have bad solder at best.

Posted on Mar 20, 2017

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SOURCE: Marshall MG50 DFX amp line out/headphones not working

Well, your problem isn't very descriptive to help troubleshoot online, but first question would be; are you using the correct size jack? The second would be have they worked before? If the answer is yes to both questions, then the problem might be the jack itself on your amp. There is a prong inside the headphone line that hugs the plug to your phones. If the prong has loosened enough where the connection is poor or not at all, you will not get any sound. If the headphone jack has NEVER worked before, than it sound like a wiring issue on your board somewhere. If you are not familiar with a soldering gun, then I would take your amp in to get it fixed. should be a minor quick fix costing anywhere between $15-$30 to have a shop do it. Hope this helps. (also try different headphones if you haven't already. Could be a bad pair)

Posted on Mar 09, 2010

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When turning my Marshal MG250 DFX on, there is a terrible buzzing sound. I have tried it on different speakers and the buzzing still occurs. It does not change in volume when i adjust the volume. Whats the...


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Yep, chalk that one up to poor design...The amplifiers are going out of balance during power up and down. Two seconds is pretty long... Try turning down the gain during power on and see if that affects it.

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