barneyg42 Posted June 5, 2016 Share Posted June 5, 2016 So I've read about this phenomenon but playing in a classic rock band it's never crossed my mind when I got a new LM3, until last night when a little impromptu jam between songs turned into a slap fest by yours truly and a total amp cut out! Switched off, switched back on and all was good! Anyone else had this? I'm pretty sure I wasn't lighting up the input gain, I use a Spectracomp that that limits quite nicely too! Am I destined to never slap my bass whilst I have this amp!!!!!????? Quote Link to comment Share on other sites More sharing options...
molan Posted June 5, 2016 Share Posted June 5, 2016 Maybe it's like a decibel meter but works on how many notes per minute you play - too many slapped notes and it slaps your wrist, saying 'enough is enough my friend, I'm turning myself off until you calm down a little' 😂 Quote Link to comment Share on other sites More sharing options...
gary mac Posted June 5, 2016 Share Posted June 5, 2016 [quote name='molan' timestamp='1465117360' post='3065326'] Maybe it's like a decibel meter but works on how many notes per minute you play - too many slapped notes and it slaps your wrist, saying 'enough is enough my friend, I'm turning myself off until you calm down a little' [/quote] This would be a welcome feature. Quote Link to comment Share on other sites More sharing options...
Mykesbass Posted June 5, 2016 Share Posted June 5, 2016 [quote name='gary mac' timestamp='1465117478' post='3065329'] This would be a welcome feature. [/quote] Would make LBGS a lot more popular Quote Link to comment Share on other sites More sharing options...
gary mac Posted June 5, 2016 Share Posted June 5, 2016 [quote name='Mykesbass' timestamp='1465117724' post='3065339'] Would make LBGS a lot more popular [/quote] Wouldn't it Quote Link to comment Share on other sites More sharing options...
Japhet Posted June 5, 2016 Share Posted June 5, 2016 Tecamps have a 'Taste' control. In my opinion this is exactly what it should do. Quote Link to comment Share on other sites More sharing options...
barneyg42 Posted June 5, 2016 Author Share Posted June 5, 2016 Really useful replies guys!! 😀😀 Quote Link to comment Share on other sites More sharing options...
molan Posted June 5, 2016 Share Posted June 5, 2016 [quote name='barneyg42' timestamp='1465120176' post='3065373'] Really useful replies guys!! 😀😀 [/quote] There's a thermal protection circuit in there to stop it overheating. Sounds to me like you've got the master volume running to high for too long and that's making the whole unit overheat. Pushing the pre gain shouldn't have this result so it's the master you need to watch. There's a fan in there to help I think. Could be this isn't working properly and that's causing overheating as well. If it happens again maybe feel the amp chassis to see if it's running hot. Quote Link to comment Share on other sites More sharing options...
Jus Lukin Posted June 5, 2016 Share Posted June 5, 2016 (edited) - Edited February 28, 2022 by Jus Lukin Quote Link to comment Share on other sites More sharing options...
barneyg42 Posted June 5, 2016 Author Share Posted June 5, 2016 (edited) [quote name='molan' timestamp='1465120598' post='3065377'] There's a thermal protection circuit in there to stop it overheating. Sounds to me like you've got the master volume running to high for too long and that's making the whole unit overheat. Pushing the pre gain shouldn't have this result so it's the master you need to watch. There's a fan in there to help I think. Could be this isn't working properly and that's causing overheating as well. If it happens again maybe feel the amp chassis to see if it's running hot. [/quote] [quote name='Jus Lukin' timestamp='1465120806' post='3065379'] I've never heard of this, and neither has it happened to either of my Mark amps- LMII and Blackline 250. There may well be a fault I'm not aware of, but other possibilities are overheating (is the fan clear and the room cool? Any dust clogging the fan or other internals?) or an impedance mismatch. Anything below 4 Ohms might cause cut outs. [/quote] I'll check on the fan, master was running at 5 so not being pushed. Cab is a modified Acme Low B with a couple of precision device 10s in it running 4ohms, this could be the problem and hopefully it's being replaced soon anyway as I'm not keen on it. Amp is brand new so shouldn't have any dust build up problems. I might default back to my TC 2x10 if the cab is the problem although I'll have to crank the master as its only 8ohm. Edited June 5, 2016 by barneyg42 Quote Link to comment Share on other sites More sharing options...
BottomE Posted June 5, 2016 Share Posted June 5, 2016 100's of gigs with Markbass stuff and not been an issue. The head rarely gets warm so i'd be surprised if it were amp related though worth checking. Like you i have TC cabs and they seem a good match at 4 ohms. Quote Link to comment Share on other sites More sharing options...
machinehead Posted June 5, 2016 Share Posted June 5, 2016 (edited) I've seen this happen with a LMII (only when running at 4 ohms) and I've read of a few others with the same problem. Have you got the gain set as per the manual? That might be worth looking into. Frank. Edited June 5, 2016 by machinehead Quote Link to comment Share on other sites More sharing options...
M@23 Posted June 5, 2016 Share Posted June 5, 2016 I had it too. My LM3 was OK, but LM2 used to flip out occasionally and do the thermal protection thing. It was a fussy old thing. Quote Link to comment Share on other sites More sharing options...
skychaserhigh Posted June 5, 2016 Share Posted June 5, 2016 I had one of these too. With the master at 12 o clock it was pretty much running at full power as it never got louder after that. They tend to go into protect mode if pushed hard. Quote Link to comment Share on other sites More sharing options...
luckydog Posted June 5, 2016 Share Posted June 5, 2016 Class D amps are unusual in how they might (mis)behave when the cone really starts flying. The amp's PSU needs to sink energy, and one might guess that under certain chaotic conditions circuit protection might cut in ? But just a guess. If so, it would be speaker dependant. HTH ! LD Quote Link to comment Share on other sites More sharing options...
barneyg42 Posted June 5, 2016 Author Share Posted June 5, 2016 (edited) [quote name='machinehead' timestamp='1465127750' post='3065446'] I've seen this happen with a LMII (only when running at 4 ohms) and I've read of a few others with the same problem. Have you got the gain set as per the manual? That might be worth looking into. Frank. [/quote] [quote name='skychaserhigh' timestamp='1465129787' post='3065464'] I had one of these too. With the master at 12 o clock it was pretty much running at full power as it never got louder after that. They tend to go into protect mode if pushed hard. [/quote] Hmm, a bit worrying as I'm almost about to pull the trigger on a lightweight 4ohm one cab solution, more health based so running two 8ohms is not really an option I want. I'll have a good look at setting up the pre gain properly, even though I was hammering the E and low B when I checked it last night to ensure the clip light was out I'll maybe knock it back a tad more. I'm thinking maybe the current cab (acme low B ) which has been played about with might be problem, possibly the ohmage is a bit out? The speaker I'm thinking of getting is a non molested straight out of the factory (albeit secondhand) jobby!! Edited June 5, 2016 by barneyg42 Quote Link to comment Share on other sites More sharing options...
barneyg42 Posted June 5, 2016 Author Share Posted June 5, 2016 P.S. Strange how most people say it's while they're slapping that this problem happens, trying to tell us something I reckon, there might be some small print in the MB manual........*not suitable for slap* Quote Link to comment Share on other sites More sharing options...
molan Posted June 5, 2016 Share Posted June 5, 2016 If it's brand new then get it back to the retailer for a once over Quote Link to comment Share on other sites More sharing options...
Norris Posted June 5, 2016 Share Posted June 5, 2016 It's karma for slapping Quote Link to comment Share on other sites More sharing options...
Guest bassman7755 Posted June 6, 2016 Share Posted June 6, 2016 [quote name='barneyg42' timestamp='1465122524' post='3065403'] I'll check on the fan, master was running at 5 so not being pushed. Cab is a modified Acme Low B with a couple of precision device 10s in it running 4ohms, this could be the problem and hopefully it's being replaced soon anyway as I'm not keen on it. Amp is brand new so shouldn't have any dust build up problems. I might default back to my TC 2x10 if the cab is the problem although I'll have to crank the master as its only 8ohm. [/quote] ACME's are notoriously inefficient and power hungry, a consequence of being designed for such good low extension. Quote Link to comment Share on other sites More sharing options...
barneyg42 Posted June 6, 2016 Author Share Posted June 6, 2016 [quote name='bassman7755' timestamp='1465190916' post='3065889'] ACME's are notoriously inefficient and power hungry, a consequence of being designed for such good low extension. [/quote] Tbh this speaker is not floating my boat anyway, the original speakers were knackered so I had a local guy put some Precision Device 10s in it and it's all mid range. Worked well with a 15 underneath using a power amp to balance the sound but as a standalone it's not great. It's just to get me by as I sell some other gear to fund a decent one speaker solution. It's bloody heavy too!! Quote Link to comment Share on other sites More sharing options...
barneyg42 Posted June 6, 2016 Author Share Posted June 6, 2016 [quote name='Norris' timestamp='1465163915' post='3065839'] It's karma for slapping [/quote] Totally!! Never again! Oh wait.......there's a slap start on one of our songs!!! Bugger! Quote Link to comment Share on other sites More sharing options...
alexclaber Posted June 6, 2016 Share Posted June 6, 2016 Yes, I've experienced this first hand. Only with slapping and only with cabs with a tweeter. It was an old Markbass head. I think it's caused by a faulty short circuit / over-current protection circuit on the amp causing a false positive and shutting the amp down to 'protect' it. Incidentally some Eminence BP102 speakers would be a much better sonic fit for the Acme. Quote Link to comment Share on other sites More sharing options...
dave_bass5 Posted June 6, 2016 Share Posted June 6, 2016 I too have had this with my old SA450. Only time it (kept) happening was when i was using a rehearsal studio's cab. I wasn't even slapping, but every time i "dug in" the amp would shut down. Turns out the cab was faulty, although i never found out exactly what that meant. Other than that, nope, not with the 3 MB heads ive regularly gigged with over the past 10 years. Quote Link to comment Share on other sites More sharing options...
luckydog Posted June 6, 2016 Share Posted June 6, 2016 [QUOTE]alexclaber said: I think it's caused by a faulty short circuit / over-current protection circuit on the amp causing a false positive and shutting the amp down to 'protect' it.[/QUOTE] Or the speaker might interact with the amp in a way causes it to take protective action to avoid damage ! LD Quote Link to comment Share on other sites More sharing options...
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