Members Bob O'Brian Posted February 1, 2009 Members Share Posted February 1, 2009 Hi I posted about this before but have been very short of time and unable to test things out until now. My CMP121 combo is acting up. It sounds fine when I first switch on, but after a few minutes it starts to go wrong, sounds to my untrained ears like the speaker is at fault. I was advised previously that it was a faulty FX loop, but having had a chance to test this can rule that out. Bass, leads, and FX loop all come clean. I even patched from the tuner out to the FX return just in case. Unfortunately I bought the amp from a company in France so I need to think carefully about how to resolve the issue, since I could end up spending a lot on shipping. If it is a duff speaker, it might be easier/cheaper just to slot in a new one, and in the meantime I can plug in an extension cab instead. Any thoughts? Link to comment Share on other sites More sharing options...
Moderators Kindness Posted February 1, 2009 Moderators Share Posted February 1, 2009 To test if it is the speaker, plug in an extension cabinet and disconnect the internal speaker. If that solves the problem, you'll know what needs to be replaced. If not, keep trouble shooting. Link to comment Share on other sites More sharing options...
Members Guttermouth Posted February 1, 2009 Members Share Posted February 1, 2009 i've never seen a speaker that would only go wonky after it was played through for a little while.not saying it couldn't happen - i just haven't seen it. my bet is on a dodgy joint on the filter caps. Link to comment Share on other sites More sharing options...
Members Bob O'Brian Posted February 1, 2009 Author Members Share Posted February 1, 2009 What's a filter cap? I did wonder if the speaker would only show problems after it was 'warmed up'- that seems more like an amp problem in a way. But the sound seems like a dying driver... Link to comment Share on other sites More sharing options...
Members Guttermouth Posted February 1, 2009 Members Share Posted February 1, 2009 What's a filter cap?I did wonder if the speaker would only show problems after it was 'warmed up'- that seems more like an amp problem in a way. But the sound seems like a dying driver... a filter cap is a capacitor that filters ripple and noise out of the power supply.the caps in question are usually pretty big and glued on the board. in general - the glue fails,puts stress on the solder joints and makes the cap have an intermittent connection that gets more obvious the longer the amp stays on or the more it vibrates. now - all that being said i have not been in a markbass amp yet and there are several other things that can cause the symptoms you're describing.there are also lethal votages present in amplifiers even after they have been turned off and unplugged - so it's probably best to take it to a qualified tech to have it looked at (after you check out kindness's speaker check up there^) Link to comment Share on other sites More sharing options...
Moderators Kindness Posted February 1, 2009 Moderators Share Posted February 1, 2009 (after you check out kindness's speaker check up there^) Which is going to show that it isn't a speaker problem. Link to comment Share on other sites More sharing options...
Members Guttermouth Posted February 1, 2009 Members Share Posted February 1, 2009 Which is going to show that it isn't a speaker problem. well you never know and me being mr pessimist and all... Link to comment Share on other sites More sharing options...
Members AluminumNeck Posted February 2, 2009 Members Share Posted February 2, 2009 Let me put on my surprised face. Sell it to some Gear aficiando over at talk bass and buy your self a old school solid state head without all the fancy 5 lb crap hoopla going on.My 49 lb Randall is thourghly abused and I mean abused. Never a problem after almopst 20 yrs of straight up abuse. Link to comment Share on other sites More sharing options...
Members erginy Posted April 19, 2019 Members Share Posted April 19, 2019 HiI posted about this before but have been very short of time and unable to test things out until now.My CMP121 combo is acting up. It sounds fine when I first switch on' date=' but after a few minutes it starts to go wrong, sounds to my untrained ears like the speaker is at fault.I was advised previously that it was a faulty FX loop, but having had a chance to test this can rule that out. Bass, leads, and FX loop all come clean. I even patched from the tuner out to the FX return just in case.Unfortunately I bought the amp from a company in France so I need to think carefully about how to resolve the issue, since I could end up spending a lot on shipping. If it is a duff speaker, it might be easier/cheaper just to slot in a new one, and in the meantime I can plug in an extension cab instead.Any thoughts?[/quote']Hello,what did you do about your amp problem?I have Markbass CMD151P Jeff Berlin and i have same problem. Link to comment Share on other sites More sharing options...
Moderators daddymack Posted April 19, 2019 Moderators Share Posted April 19, 2019 Hello, what did you do about your amp problem? I have Markbass CMD151P Jeff Berlin and i have same problem. you may be about ten years too late... Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.