Hey guys, Long time GK user here, in the past I owned 2 RB800 and a RB700. Now have a MB212 for portability. I love how the GK MB212 usually delivers on various gig settings. However yesterday when I turned it on during soundcheck at a venue. It only played at 5% of the expected volume when gain & master volumes were set at 12 o'clock, same as usual, sometimes lower. Check it again this morning, same thing. Sound like a 10 watt amp. If I turn up the gain, boost & master volume I get a little more volume but a lot of hiss. I have a soundcheck this afternoon and another show tonight. Is this an issue anyone else has experienced? Is there a way to sort this out quickly? PS: tested with various cables and basses, those were not at fault. Any suggestion would be welcome. Thanks Eric
Sorry to hear about that, terrible timing. Aside from the testing that you've already done, I'm not sure how much is left to do aside from taking it to a tech. I have experienced issues with my MB amp (not a combo) in the past, but nothing like what you're describing. The types of failures I've experienced are those that tended to put the amp in safe-mode.
Effects loop jacks can cause this sort of issue. If it has one, link Send and Return with a short signal cable to see if that helps.
Unfortunately Paul, the GK MB Combos don't have a send and return so beam2611 is going to have to rely on either GK directly or a local amp tech to diagnose and fix the problem. I suggest he take it to the closest L&M in Montreal. TD
Bought it second hand, Just realized I got a first Gen MB212. No fx loop. no -10db Pad. However, I got a lead on a good guitar amp repair tech. He says he's dealt with the GK amps issues often. He thinks it's either the pre-amp or output section. Going to see him tomorrow.
Your amp contains three basic sections. Pre-amp, power amp and power supply. Two out of three ain’t bad!