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Markbass farting out and overheating
- Thread starter brad70
- Start date
Brad, my Markbass F1 only shutdown when trying to drive a load that dipped below 4 ohms. Comes right back on. It is part of the design to keep it from frying.
You may have a low line condition.
Long extension cords & a light gauge cord #16 or #18 AWG
is always a problem on outdoor gigs..
Try a heavy gauge AC extension cord #12 AWG.
Long extension cords & a light gauge cord #16 or #18 AWG
is always a problem on outdoor gigs..
Try a heavy gauge AC extension cord #12 AWG.
Had this same problem with a LM III that was returned to the shop by a customer - sure enough as soon as you pushed it relatively hard into the 410 4ohm cab it shut down... tried different cabs, different ohmage, speaker cables, guitars etc. it sometimes happened and sometimes didn't... Not quite sure what the problem is but it seemed to like 8 ohms better than 4 for some reason?
Another strange markbass thing I've noticed: some of the heads seem to sound better if you chain 2 cabs together rather than running the same 2 cabs off the 2 speaker outputs? That is a strange one for me... dunno what kind of internal wiring would be responsible for that!?
Another strange markbass thing I've noticed: some of the heads seem to sound better if you chain 2 cabs together rather than running the same 2 cabs off the 2 speaker outputs? That is a strange one for me... dunno what kind of internal wiring would be responsible for that!?
Son of Bovril, that is exactly what is happening to my Markbass products. I am only using Markbass 8 ohm cabs, thought I would be safe.
I have only daisy chained the cabs thus far.
I have only daisy chained the cabs thus far.
We still have that amp sitting around at the shop, we replaced it for the owner at no charge, but it seems to be working though, at least in the shop, but I wouldn't trust it at a gig... so not quite sure what the problem was or if there ever was one, maybe it was just human error, but I did try to problem solve the issue in every way I could think of without taking it apart.
I'd say return it but the fact that it is happening to you with all of your heads is more concerning, there is obviously something that is causing it but I can't for the life of me think what it could be?
just to be certain you've covered your bases: this is happening at different venues, and you've checked it with different combinations of cabs, different power cables, different speaker cables different guitars and different instrument leads, You are using a proper gauge speaker cable?
I'd say return it but the fact that it is happening to you with all of your heads is more concerning, there is obviously something that is causing it but I can't for the life of me think what it could be?
just to be certain you've covered your bases: this is happening at different venues, and you've checked it with different combinations of cabs, different power cables, different speaker cables different guitars and different instrument leads, You are using a proper gauge speaker cable?
I am going to buy a larger power supply and try it before I sell them. I love the sound, and the weight.
Thanks Russell L, but it only happens with the Markbass.
Thanks Russell L, but it only happens with the Markbass.
No prob, man. The only time my LMIII cut off on me was when I was trying to hook up the speaker in my Trace Elliot combo to it to see what it sounded like. I accidentally connected the LMIII to the GP7-SM head instead of the speaker, and it cut right off. After seeing my mistake I 'bout had a heart attack. But, it came right back on once I corrected the connection and has been fine ever since. That's been many months ago. I gig it regularly.
I hope you get sorted. Weird that it does it at different places. That makes me wanna think it's someting in your connections. But, also odd that all your stuff does it. Sheez.
Maybe try changing the fuse...
Might be a quick fix, or contact the service dept and see what they say.
Might be a quick fix, or contact the service dept and see what they say.
My LM3 has yet to fail under any circumstance. I use it with a 2 x 10 cab for small rooms and add a 1 x 15 when I need more. Both are 8 ohm cabs, using quality speaker cables and no power conditioner...just plugging into a quad box then into the nearest wall outlet. So far no issues and I run almost exactly the same amp settings as you've described with passive basses, sometimes adding a Sadowsky pre amp/DI before the amp.
With your diagnosis of your connection chain under a variety of set ups, my guess is there is there may be something glitchy with your power conditioner. You might also double check the power conditioner's power output dip switch, if there is one, to make sure it's set correctly and didn't somehow get changed.
With your diagnosis of your connection chain under a variety of set ups, my guess is there is there may be something glitchy with your power conditioner. You might also double check the power conditioner's power output dip switch, if there is one, to make sure it's set correctly and didn't somehow get changed.
yeah the new SMTP class-D amps seem to be a lot more picky about power than the older heavier guys, probably because they are more efficient in their usage of it and also because they have more modern protection circuits
Did you try removing your power conditioner? What country were your amps set to be used in? Markbass amps are set for a specific country's voltage restrictions.
Try contacting Peter Murray on here. He was very helpful when my amp was having issues and has been to many other Markbass owners.
Try contacting Peter Murray on here. He was very helpful when my amp was having issues and has been to many other Markbass owners.
It just happens some of them shut down some of them dont.
Most of they ones I have played shut down. Not saying im a special wizard or something. But at a few open mics where a amp is being shared. 4 guys will do just fine with it. and then another 2 guys will have it shut down and then they just keep toggling the power switch to make it reset. Then it is just a matter of time before it goes.....pop.
Even though it is rated at 4ohms. Running a 4ohm load is still going to generate more heat. so it is just a matter of time before thermal bye bye.
So if it is possible to maybe improve the ventilation, raise it up, add more vent holes, or maybe put a fan on it. Till yah get a new rig.
Even if you dont plan on running a 2ohm load. Its good to consider a amp that is 2ohm stable. 2ohms is way more heat than 4ohms and if the manufacture designed the amp, mainly the heat sink to run 2ohms it should do 4ohms all night.
Most of they ones I have played shut down. Not saying im a special wizard or something. But at a few open mics where a amp is being shared. 4 guys will do just fine with it. and then another 2 guys will have it shut down and then they just keep toggling the power switch to make it reset. Then it is just a matter of time before it goes.....pop.
Even though it is rated at 4ohms. Running a 4ohm load is still going to generate more heat. so it is just a matter of time before thermal bye bye.
So if it is possible to maybe improve the ventilation, raise it up, add more vent holes, or maybe put a fan on it. Till yah get a new rig.
Even if you dont plan on running a 2ohm load. Its good to consider a amp that is 2ohm stable. 2ohms is way more heat than 4ohms and if the manufacture designed the amp, mainly the heat sink to run 2ohms it should do 4ohms all night.
strange you say that, cause the LM III head that was giving trouble was in a pretty tight rack and also seemed to exhibit the shutdown more at 4 ohms than at 8...?
for sure, most likely the problem.
Lower impedance = more current. More current = more heat.
more heat, poor ventilation ,and poorly designed heat sink = thermal shutdown.
Is it doing it with both speakon speaker plugs/leads & jack plugs/leads? I remember my LMII cut out once when I used speakon. Never did using a jack speaker lead.
Worth a try??
Worth a try??
While you are troubleshooting, I would suggest you check the speaker cables.
They can test fine with a meter, and seem to be working fine, but I have seen several speaker cables short out when they were moved or from vibration. When this happens, the cable shorting.
Recently experienced this with a Peavey PA system. The speaker cables tested fine, but if one of the cables was jarred a little, instant short. Insulated the cable connections, problem solved.
As others have mentioned, you need to do more testing by removing the power conditioner from the circuit, but you also need to eliminate every possible problem one device at a time.
Good luck.
They can test fine with a meter, and seem to be working fine, but I have seen several speaker cables short out when they were moved or from vibration. When this happens, the cable shorting.
Recently experienced this with a Peavey PA system. The speaker cables tested fine, but if one of the cables was jarred a little, instant short. Insulated the cable connections, problem solved.
As others have mentioned, you need to do more testing by removing the power conditioner from the circuit, but you also need to eliminate every possible problem one device at a time.
Good luck.
after all the techy comments I must tell you that I feel you are simply pushing the amp towards its limit.
On many amps, and for sure on Markbass, the position of the knobs has zero importance. More, the volume knob has a really non progressive, non-linear behaviour, so that with the volume knob at 9 o' clock and the input gain properly set (just a hint before unwanted clipping) for example, maybe you are using half the power, and going to 11-12 could actually hit the maximum wattage and thus, in certain conditions (4 ohms, heat, sustained playing), trigger the protection circuit or the thermal safe.
But, just to be honest, in this situation you should experiment a huge SPL coming from your system, given you are not completely deaf.
In the absurd case that you actually need more SPL, just add speaker cone area with good sensitivity, and you are done.
In my past, I owned MB cabs, and found they have a good low-end but are a little mid-shy (210 and 410), so they "suck" a lot of juice from your amp to be heard at stadium levels.
Maybe I'm wrong, maybe it's that "power conditioner", maybe a fault somewhere in the signal chain, but what I said is rather well known by some...
While I'll +1 your general points, his issue (as mentioned by many above) seems to not be the heads at all. The probability of multiple heads working fine for a long period of time, and then ALL of them having an identical issue starting at the same time is so improbable as to be virtually statistically impossible. I (and so many others) have driven these heads HARD at 4ohms right into the limiting circuit, and they don't even get warm).
The limiting design of the Markbass heads will result in the head significantly compressing on the low end LONG before you reach shutdown. The primary cause of the few shutdown issues reported over the years by Markbass users seem to be:
1) Cabs or combinations of cabs that dip below the 4ohm minimum. The Markbass heads do seem to be more sensitive to this than other heads, micro's or not.
2) Using 'off brand' (i.e., non-Neutrik) Speakon cables with the Neutrik combo jacks used in the Markbass heads.
As most have said, something else going on here... cable, power conditioner, whatever.
